HomeMy WebLinkAboutAppendix F - Geotechnical Report
GEOTECHNICAL UPDATE
BUILDER’S MAX
APN 371-150-001 & 371-150-002
GRAND AVENUE AT KATHRYN WAY
LAKE ELSINORE, CALIFORNIA
PREPARED FOR
BUILDER’S MAX
TEMECULA, CALIFORNIA
FEBRUARY 22, 2022
PROJECT NO. T2719-22-02
Project No. T2719-22-02
February 22, 2022
Builder’s Max
31938 Temecula Parkway, Unit A369
Temecula, CA 92592
Attention: Mr. Steve Galvez
Subject: GEOTECHNICAL UPDATE
BUILDER’S MAX
APNS 371-150-001 & 371-150-002
GRAND AVENUE AT KATHRYN WAY
LAKE ELSINORE, CALIFORNIA
Dear Mr. Galvez:
In accordance with your authorization of Proposal No. IE-2887 dated December 1, 2021, Geocon West
Inc. (Geocon) herein submits the results of our geotechnical update and percolation testing for the subject
site. The accompanying report presents the results of our previous study, results of recent percolation
testing, and updated geotechnical parameters in accordance with the 2019 California Building Code for
the proposed light industrial development. The site is considered suitable for development provided the
recommendations of this report are followed.
Should you have questions regarding this report, or if we may be of further service, please contact the
undersigned at your convenience.
Very truly yours,
GEOCON WEST, INC.
Lisa A. Battiato
CEG 2316
Petrina Zen
PE 87489
Joseph J. Vettel
GE 2401
LAB:PZ:JJV:hd
(e-mail)
Geocon Project No. T2719-22-02 - i - February 22, 2022
TABLE OF CONTENTS
1. PURPOSE AND SCOPE ...................................................................................................................... 1
2. SITE AND PROJECT DESCRIPTION ................................................................................................ 2
3. GEOLOGIC SETTING ......................................................................................................................... 3
4. GEOLOGIC MATERIALS .................................................................................................................. 3
4.1 General ........................................................................................................................................ 3
4.2 Undocumented Artificial Fill (afu) ............................................................................................. 3
4.3 Lacustrine Deposits (Ql) – not a mapped unit ............................................................................ 4
4.4 Alluvial Fan Deposits (Qyf) ....................................................................................................... 4
4.5 Pauba Formation (Qpfs) ............................................................................................................. 4
5. GROUNDWATER ............................................................................................................................... 4
6. GEOLOGIC HAZARDS ...................................................................................................................... 5
6.1 Seismic Hazard Analysis ............................................................................................................ 5
6.2 Seismicity ................................................................................................................................... 6
6.3 Liquefaction ................................................................................................................................ 6
6.4 Expansive Soil ............................................................................................................................ 7
6.5 Landslides ................................................................................................................................... 7
6.6 Rock Fall Hazards....................................................................................................................... 8
6.7 Slope Stability ............................................................................................................................. 8
6.8 Tsunamis and Seiches ................................................................................................................. 8
7. SITE INFILTRATION.......................................................................................................................... 8
8. CONCLUSIONS AND RECOMMENDATIONS .............................................................................. 10
8.1 General ...................................................................................................................................... 10
8.2 Soil Characteristics ................................................................................................................... 11
8.3 Minimum Resistivity, pH, and Water-Soluble Sulfate ............................................................. 12
8.4 Grading ..................................................................................................................................... 13
8.5 Earthwork Grading Factors ....................................................................................................... 15
8.6 Utility Trench Backfill .............................................................................................................. 15
8.7 Seismic Design Criteria ............................................................................................................ 16
8.8 Mat Foundation ......................................................................................................................... 18
8.9 Foundation Settlement .............................................................................................................. 19
8.10 Lateral Design ........................................................................................................................... 19
8.11 Exterior Concrete Flatwork ...................................................................................................... 20
8.12 Retaining Walls ........................................................................................................................ 21
8.13 Preliminary Pavement Recommendations ................................................................................ 23
8.14 Temporary Excavations ............................................................................................................ 26
8.15 Site Drainage and Moisture Protection ..................................................................................... 27
8.16 Grading and Foundation Plan Review ...................................................................................... 27
LIMITATIONS AND UNIFORMITY OF CONDITIONS
LIST OF REFERENCES
TABLE OF CONTENTS (Concluded)
Geocon Project No. T2719-22-02 - ii - February 22, 2022
MAPS AND ILLUSTRATIONS
Figure 1, Vicinity Map
Figure 2, Geotechnical Map
Figures 3 and 4, DE Evaluation of Earthquake-Induced Settlements, Boring B-1 (Geocon 2016)
Figures 5 and 6, MCE Evaluation of Earthquake Induced Settlements, Boring B-1 (Geocon 2016)
APPENDIX A
EXPLORATORY EXCAVATIONS
Figures A-1 through A-4, Percolation Boring Logs
Figures A-5 through A-8, Percolation Test Data
Boring Logs, Geocon 2016
APPENDIX B
LABORATORY TESTING
Figures B-1 through B-4, Grain Size Distribution Test Results
Laboratory Test Results, Geocon 2016
APPENDIX C
RECOMMENDED GRADING SPECIFICATIONS
Geocon Project No. T2719-22-02 - 1 - February 22, 2022
GEOTECHNICAL UPDATE
1. PURPOSE AND SCOPE
This report presents the results of our geotechnical update and percolation testing for design of site storm
water infiltration structures for the proposed light industrial development to be constructed within APNs
371-150-001 & -002 north of Grand Avenue and Kathryn Way in Lake Elsinore, California.
Four buildings are planned within the central and southwestern area of the site. A building materials
storage yard is planned for the northeastern area of the site, within the recommended building set back
zone along the Elsinore fault. The site location is depicted on the Vicinity Map, Figure 1. The purposes
of this geotechnical update are to provide geotechnical and seismic design parameters per the 2019
California Building Code (CBC) and present infiltration rates at four locations proposed for site BMP s.
In addition, this report provides recommendations for remedial grading, shallow foundations, concrete
slab-on-grade, concrete flatwork, preliminary pavement sections, lateral loading, and retaining walls.
This update also includes a review of readily available published and unpublished geologic literature
(see List of References).
The scope of this update included performing a site reconnaissance, field exploration, percolation
testing, laboratory testing, engineering analyses and preparing this report. We drilled four percolation
borings to depths of four feet on the site on February 2, 2022 and percolation testing was performed on
February 3, 2022. The recent boring logs and percolation data sheets are presented in Appendix A along
with previous geotechnical borings within the proposed development area of the site (Borings 1 through
6, and 10). The Geologic Map, Figure 2, presents the approximate locations of the borings and
percolation tests. Appendix A provides a detailed discussion of the field investigation and includes logs
of the borings with moisture and dry density results and percolation test results. Details of the laboratory
tests and a summary of the test results are presented in Appendix B and on the boring logs in
Appendix A.
Recommendations presented herein are based on analyses of data obtained from this study and the
previous investigation performed by Geocon in 2016 and our understanding of proposed site
development. References reviewed to prepare this report are provided in the List of References. If project
details vary significantly from those described herein, Geocon should be contacted to evaluate the
necessity for review and possible revision of this report.
Geocon Project No. T2719-22-02 - 2 - February 22, 2022
2. SITE AND PROJECT DESCRIPTION
The site is located northeast of Grand Avenue and northwest of Kathryn Way in Lake Elsinore,
California. The property is bounded on the northwest by rural properties and northeast by Lake Elsinore
and habitat mitigation land. The existing grades range from approximately 1,283 feet above mean sea
level (MSL) near Grand Avenue to approximately 1,271 feet MSL near the northeastern most proposed
building. The site is generally flat with a few isolated trees and a very low growth of recent grass.
The site is at approximately latitude 33.63384 and longitude -117.3329.
A site plan depicting the building locations and finish floor elevations indicates finish grades will be
1,271 to 1,267 feet MSL resulting in cuts of approximately 5 to 12 feet. The site BMPs will be located
along Kathryn Way and northeast of the paved storage yard. The Preliminary Grading Plan dated
December 31, 2021, provided by Grant Becklund, Civil Engineer was utilized as the base for our
Geologic Map, Figure 2.
We expect that the proposed light industrial buildings will either be concrete tilt up structures or
wood/steel framed buildings with stucco exteriors. We expect spread footing foundations and slab on
grade floors.
Due to the preliminary nature of the design at this time, wall and column loads were not available.
We anticipate that column loads for the proposed structures will be up to 150 kips, and wall loads will
be up to 2 kips per linear foot.
The site descriptions and proposed development are based on a site reconnaissance, review of published
geologic literature, our field investigation, and discussions with members of the project team.
If development plans differ from those described herein, Geocon should be contacted for review of the
plans and possible revisions to this report.
Geocon Project No. T2719-22-02 - 3 - February 22, 2022
3. GEOLOGIC SETTING
The site is located within the Peninsular Ranges Geomorphic Province (Province) at the boundary of
the Perris and Santa Ana Mountain Blocks. In the vicinity of the site, the Perris Block is characterized
by highlands which display elevated erosional surfac es surrounded by alluviated and fault bounded
valleys. The Santa Ana Mountains Block is characterized by heterogeneous granitic bedrock with a
moderate amount of volcanic and metamorphic rocks, and some terrestrial sedimentary rocks.
The Peninsular Ranges are bound by the Transverse Ranges (San Gabriel and San Bernardino
Mountains) to the north and the Colorado Desert Geomorphic Province to the east. The Peninsular
Ranges Geomorphic Province extends westward into the Pacific Ocean and southward to the tip of
Baja California. Overall, the Province is characterized by Cretaceous -age granitic rock and a lesser
amount of Mesozoic-age metamorphic rock overlain by terrestrial and marine sediments. Faulting
within the Province is typically northwest trending and i ncludes the San Andreas, San Jacinto,
Elsinore, and Newport -Inglewood faults. Locally, the site is in the Elsinore Valley, a pull -apart basin
as a result of a step-over within the Elsinore Fault Zone. Conversely, Rome Hill located just to the
southeast (and the moderate relief hill located in the northeastern portion of the site) are the result of
compressional stresses of strike slip faulting within the zone. The W illard strand of the Elsinore fault
zone is mapped in the eastern portion of the site. The en tire site is within a Riverside County Fault
Hazard Zone.
4. GEOLOGIC MATERIALS
4.1 General
Site geologic materials encountered consist of undocumented artificial fill, lacustrine deposits, alluvial
fan deposits and the fanglomer ate member of the Pauba Formation. The descriptions of the soil and
geologic conditions are shown on the excavation logs located in Appendix A, the Geotechnical Map
(Figure 2), and described herein; generally following the nomenclature of Morton and Weber, 2003
(see List of References).
4.2 Undocumented Artificial Fill (afu)
Undocumented fill was observed in the excavations to depths of approximately 14 feet within the central
and eastern portions of the site. We understand that the fill was placed on the site after flooding in the
1980’s. There is no documentation of removals beneath the fill or geotechnical testing and observation
of fill placement. Therefore, it is considered undocumented. The unit consists of silty to clayey sands,
silts, and clays which are loose (soft) to medium dense (firm) and dry to moist, gray to brown, and has
varying amounts of debris, including rocks and asphaltic concrete.
Undocumented fill is also present within the fault trench excavations as loose backfill.
Geocon Project No. T2719-22-02 - 4 - February 22, 2022
4.3 Lacustrine Deposits (Ql) – not a mapped unit
Lacustrine (lake) deposits underlie the undocumented fill in the central and eastern portions of the site at
depths of 4 to 30 feet (Borings B-5 and B-6). This unit consists of silty sands and silts that are thickly
bedded and have abundant carbonate throughout the unit. Porosity was observed within these deposits at
depths of 13 to 23 feet. The lacustrine deposits are fine to coarse, moist to wet, and loose (soft) to dense
(stiff). The soil color is generally olive grey to yellowish brown. Consolidation test results generally
showed 0 to 0.6 percent collapse with one sample showing 11.8 percent collapse when inundated with
water.
4.4 Alluvial Fan Deposits (Qyf)
Alluvial fan deposits were encountered at the surface in the western portion of the site and underlying
the undocumented fill and lacustrine deposits in the central and eastern portions of the site to depths of
51½ feet. This unit consists predominately of silty sand that is medium dense to very dense, moist to wet,
reddish brown to dark gray with some mottling. The unit contained variable amounts of clay and gravel
in localized deposits.
4.5 Pauba Formation (Qpfs)
The fanglomerate member of the Pauba Formation was encountered at depths of 19½ to 51½ feet within
the western and central portions of the site. As encountered, the Pauba consists of well graded to silty
sandstone which is moist to wet, and poorly to non-indurated. The Pauba is moderately hard to very hard.
5. GROUNDWATER
Groundwater was encountered in boring B -1 at a depth of 36 feet, 11 inches, and it stabilized at
26 feet, 6 inches during drilling. It was also encountered in boring B -12 (in the northeastern area of
the property, outside of the current project limits ) at a depth of 40 feet and rose to a height of 35 feet
during drilling. California Department of Water Resources well data indicates groundwater has been
measured at depths of approximately 56 to 58 feet below ground surface in nearby wells. Depth to
groundwater may also fluctuate based on the water level in Lake Elsinore during annual variations .
Groundwater should be anticipated at or slightly above the lake water elevation. During the rainy
season, localized perched water conditions may develop above less permeable units that may require
special consideration during grading operations. Groundwater elevations and seepage are dependent
on seasonal precipitation, irrigation, and land use, among other facto rs, and vary as a result.
Geocon Project No. T2719-22-02 - 5 - February 22, 2022
6. GEOLOGIC HAZARDS
6.1 Seismic Hazard Analysis
The site is located within a Riverside County Fault Zone. The W illard branch of the Elsinore Fault
Zone bisects the site as shown on the Regional Geologic Map (Figure 3). Terra Geosciences
performed fault trenching for the project and reported their results under separate cover
(2015, 2016). These reports were approved by the County Geologist in Novembe r, 2016.
We understand that the locations of the faults and fault trenches were surveyed and building setback
zones were established for the project. The approximate building setback zone is depicted on Figure
2 herein.
Significant active faults within a 100 kilometer radius of the site are listed in Table 6.1.1 and include
directions and distances from the site, and the potential earthquake magnitudes. Historic earthquakes
of magnitude 6.0 and greater within 100 miles of the site are listed in Table 6.1.2 and include the fault
names, directions and distances from the site, and the magnitudes of the seismic events.
TABLE 6.1.1
SIGNIFICANT ACTIVE FAULTS WITHIN 100 KM OF THE SITE
Fault Direction
Distance from
Site (km) Magnitude
Elsinore E 0 6.8
Casa Loma (San Jacinto) NE 34 6.9
Claremont (San Jacinto) NE 37 6.9
Chino-Central Avenue NNW 40 6.7
Newport Inglewood W 48 7.1
Whittier NW 51 6.8
San Andreas NNE 56 7.5
Cucamonga NW 61 6.9
Coronado Bank SW 69 7.2
San Diego Trough SW 85 7.2
Rose Canyon SW 90 7.2
Geometry: BT = blind thrust, LL = left lateral, N = normal, O = oblique, R = reverse, RL = right lateral, SS = strike slip.
Information Sources: a = Cao, T., Bryant, W.A., Rowshandel, B., Branum, D., and Wills, C.J., 2003, The Revised 2002
California Probabilistic Seismic Hazard Maps, including Appendices A, B, and C, dated June; b = online Fault Activity
Map of California website, maps.conservation.ca.gov/cgs/fam/, as of 1/2017.
n/a = data not available.
Geocon Project No. T2719-22-02 - 6 - February 22, 2022
6.2 Seismicity
As with all of southern California, the site has experienced historic earthquakes from various regional
faults. The seismicity of the region surrounding the site was formulated based on research of an electronic
database of earthquake data. A number of earthquakes of moderate to major magnitude have occurred in
the southern California area within the last 100 years. A partial list of these earthquakes is included in
the Table 6.2.
TABLE 6.2
HISTORIC EARTHQUAKE EVENTS WITH REPECT TO THE SITE
6.3 Liquefaction
Liquefaction is a phenomenon in which loose, saturated, relatively cohesionless soil deposits lose shear
strength during strong ground motions. Primary factors controlling liquefaction include intensity and
duration of ground motion, gradation and density characteristics of the subsurface soils, in-situ stress
conditions, and the depth to groundwater. Liquefaction is typified by a loss of shear strength in the
liquefied layers due to rapid increases in pore water pressure generated by earthquake accelerations.
The current standard of practice, as outline d in the “Recommended Procedures for Implementation of
DMG Special Publication 117, Guidelines for Analyzing and Mitigating Liquefaction in California”
and “Special Publication 117A, Guidelines for Evaluating and Mitigating Seismic Hazards in
California” requires liquefaction analysis to a depth of 50 feet below the lowest portion of the proposed
structure. Liquefaction typically occurs in areas where the soils below the water table are composed
of poorly consolidated, fine to medium -grained, primarily sandy soil. In addition to the requisite soil
conditions, the ground acceleration and duration of the earthquake must also be of a sufficient level to
induce liquefaction.
Earthquake
(Oldest to Youngest)
Near Redlands July 23, 1923 6.3 26 NNE
Long Beach March 10, 1933 6.4 36 W
Tehachapi July 21, 1952 7.5 134 NW
San Fernando February 9, 1971 6.6 81 NW
Whittier Narrows October 1, 1987 5.9 52 WNW
Sierra Madre June 28, 1991 5.8 58 NW
Landers June 28, 1992 7.3 65 NE
Big Bear June 28, 1992 6.4 49 NE
Northridge January 17, 1994 6.7 80 WNW
Hector Mine October 16, 1999 7.1 90 NE
Ridgecrest China Lake Fault July 5, 2019 7.1 148 N
Date of Earthquake Magnitude
Distance to
Epicenter
(Miles)
Direction
to
Epicenter
Geocon Project No. T2719-22-02 - 7 - February 22, 2022
A review of the County of Riverside Land Information System indicates that the site is located within
an area designated as having a high potential for liquefaction.
Liquefaction analysis of the soils underlying the site (approximate elevation of 1,262 through
1,212 feet MSL and 1,270 to 1,250 feet MSL) was performed using an updated version of the
spreadsheet template LIQ2_30.WQ1 developed by Thomas F. Blake (1996). This program utilizes the
1996 NCEER method of analysis. This semi -empirical method is based on a correlation between values
of Standard Penetration Test (SPT) resistance and field performance data.
The liquefaction analysis was performed for a Design Earthquake level by using a “model” historic
high groundwater table of 5 feet below the ground surface, a magnitude 6.49 earthquake, and a peak
horizontal acceleration of 0.585g (⅔PGAM). The enclosed liquefaction analyses, included herein for
boring B-1, indicates that the alluvial and lacustrine soils below the proposed foundation level would
be prone to up to approximately 3 inches of liquefaction settlement during Design Earthquake ground
motion (see enclosed calculation sheets, Figures 3 and 4). The site could be prone to differential
settlements up to approximately 1.5 inches over a distance of 50 feet at the ground surface.
We understand that the intent of the Building Code is to maintain “Life Safety” during Maximum
Considered Earthquake level events. Therefore, additional analysis was performed to evaluate the
potential for liquefaction during a MCE event. The struct ural engineer should evaluate the proposed
structure for the anticipated MCE liquefaction induced settlements and verify that anticipated
deformations would not cause the foundation system to lose the ability to support the gravity loads
and/or cause collapse of the structure.
The liquefaction analysis was also performed for Maximum Considered Earthquake levels by using a
“model” historic high groundwater table of 5 feet below the ground surface, a magnitude 7.71 earthquake,
and a peak horizontal acceleration of 0.877g (PGAM). The enclosed liquefaction analysis, included herein
for boring B-1, indicates that the alluvial and lacustrine soils below the proposed foundation would be
prone to up to approximately 3 inches of liquefaction settlement during Maximum Considered
Earthquake ground motion (see enclosed calculation sheets, Figures 5 and 6).
6.4 Expansive Soil
The geologic units generally consist of silty sands with some clay deposits . Laboratory testing results
indicate the soils tested exhibit a “very low” expansion potential (EI of 20 or less) as defined by ASTM
International (ASTM) D4829.
6.5 Landslides
There are no steep slopes on or adjacent to the site. Therefore, landslides are not a design consideration
for the site.
Geocon Project No. T2719-22-02 - 8 - February 22, 2022
6.6 Rock Fall Hazards
The closest mountains are the Santa Ana Mountains, approximately 1,000 feet to the west. Due to
shallow moderate slope angle, the moderate soil development, and abundant brush on the slopes, rock
falls are not a design consideration for the site.
6.7 Slope Stability
Based on the preliminary site plan and relatively flat site topography, it does not appear that significant
slopes will be constructed. Therefore, slope stability will not be a design consideration for the site.
6.8 Tsunamis and Seiches
A tsunami is a series of long period waves generated in the ocean by a sudde n displacement of large
volumes of water. Causes of tsunamis include underwater earthquakes, volcanic eruptions, or offshore
slope failures. The first order driving force for locally generated tsunamis offshore southern California
is expected to be tectonic deformation from large earthquakes (Legg, et al., 2003). The site is located
more than 22 miles from the nearest coastline with a mountain range in between; therefore, risk
associated with tsunamis is not a design consideration.
A seiche is a run-up of water within a lake or embayment triggered by fault - or landslide-induced
ground displacement. Lake Elsinore is located approximately 1,600 feet north of the site and has a
water surface elevation of approximately 1,238 feet MSL. Lake water surface elevations are 1,244 feet
MSL and outflow channel elevations are 1,255 feet MSL. The hill located just northwest of the
proposed development acts as a barrier between the site and the lake, with a peak of approximately
1,283 feet above MSL. Further, the proposed development elevations will be approximately 1,268 feet
above MSL. The civil engineer should use these criteria to evaluate if there is a hazard for a seiche to
affect the site.
7. SITE INFILTRATION
Percolation testing was performed in accordance with the procedures outlined in Riverside County Flood
Control and Water Conservation District LID BMP, Appendix A for the proposed infiltration structures
along the eastern area of the site. The percolation test locations are depicted on the Geologic Map, Figure
2.
Percolation borings P-1 through P-4 were excavated at the proposed BMP locations at depths of 4 feet
per Grant Becklund. Three-inch diameter perforated pipe wrapped in filter fabric was placed within the
borings. Gravel was placed at the bottom of the hole and around the pipe. Percolation testing began
within 24 hours after the holes were presaturated. Percolation data sheets are presented in Appendix A of
this report. Results of the converted percolation test rates to infiltration test rates are presented in
Table 7.
Geocon Project No. T2719-22-02 - 9 - February 22, 2022
TABLE 7
INFILTRATION TEST RATES FOR PERCOLATION AREAS
Parameter P-1 P-2 P-3 P-4
Depth (inches) 48 48 48 48
Test Type Sandy Normal Sandy Normal
Change in head over time: ∆H (inches) 4.2 2.2 3.8 1.3
Average head: Havg (inches) 30.9 22.9 25.1 21.5
Time Interval (minutes): ∆t (minutes) 10 30 10 30
Radius of test hole: r (inches) 4 4 4 4
Tested Infiltration Rate: It (inches/hour) 1.5 21.4 1.7 13.5
The results of the infiltration testing indicate that infiltration at the locations tested ranged from 1.5 to
21.4 inches per hour.
The in-situ field percolation tests performed provide short-term infiltration rates, which apply mainly to
the initiation of the infiltration process due to the short time of the test (hours instead of days) and the
amount of water used. Where appropriate, the short-term infiltration rates shall be converted to
long-term infiltration rates using reduction factors depending on the degree of infiltrate quality,
maintenance access and frequency, site variability, subsurface stratigraphy variation, and other factors.
The small-scale percolation testing cannot model the complexity of the effect of interbedded layers of
different soil composition, and our test results should be considered only as index values of infiltration
rates.
Geocon Project No. T2719-22-02 - 10 - February 22, 2022
8. CONCLUSIONS AND RECOMMENDATIONS
8.1 General
8.1.1 It is our opinion that neither soil nor geologic conditions were encountered during the
investigation that would preclude construction of the proposed project provided the
recommendations presented herein are followed and implemented during design and
construction.
8.1.2 Up to 12 feet of undocumented artificial fill was encountered during the site investigation
within the planned structural improvement areas. The undocumented fill encountered is
believed to have been placed to elevate the land surface after flooding in the 1980’s. De eper
fill may exist in other areas of the site that were not directly explored. The undocumented fill,
in its present condition, is not suitable for direct support of proposed foundations, slabs, or
additional fill. The undocumented fill and site soils are suitable for re-use as engineered fill
provided the recommendations in the Grading section of this report are followed.
8.1.3 Several fault trenches have been excavated within the site. We understand that these
excavations were surveyed and loosely backfilled. Trenches within area to receive structural
or flatwork improvements should be located, re-excavated, and backfilled in accordance with
the recommendations herein during grading.
8.1.4 Active faulting is present in the eastern portion of the site. Building setbacks were
recommended by Terra Geoscience. The fault and building setback locations should be
plotted o n the project grading plans and clearly staked by survey in the field for compliance
during site construction.
8.1.5 The enclosed seismically -induced settlement analysis indicates that alluvial soils underlying
the site could be prone to up to approximately 3 inches of liquefaction settlement as a result
of the Design Earthquake peak ground acceleration (⅔PGA M). The resulting differential
settlement at the ground surface is anticipated to be up to approximately 1.5 inches over a
horizontal distance of 50 feet. The foundation recommendations presented in this report are
intended to reduce the effects of differential settlement on proposed structures.
8.1.6 The upper 8 to 12 feet of site soils consist of undocumented fill or compressible alluvial soils
which should be removed and replaced with compacted fill within areas to receive
improvements during grading.
8.1.7 Where relatively loose wet, or soft soils are encountered in the site excavations, subgrade
stabilization may be required prior to placing fill or installing utilities. The contractor should
be prepared to mitigate these conditions.
Geocon Project No. T2719-22-02 - 11 - February 22, 2022
8.1.8 Subsequent to the recommended grading, the proposed structures may be supported on a
reinforced concrete mat foundation system deriving support on newly placed engineered fill.
A mat foundation is more capable of mitigating the effects of differential settlement of the
underlying soils, as well as distributing the structural loads of the building, thereby minimizing
loads imposed on the supporting soils.
8.1.9 It is anticipated that stable excavations for the recommended grading associated with the
proposed structures can be achieved with sloping measures. However, if excavations in
proximity to an adjacent property line , utility lines, and/or structures are required, special
excavation measures may be necessary in order to maintain lateral support of existing
improvements. Excavation recommendations are provided in the Temporary Excavations
section of this report.
8.1.10 Where new paving is to be placed, we recommend that existing undocumented fill and soft
lacustrine/alluvial soils be excavated and properly compacted for paving support.
As a minimum, the upper 24 inches of subgrade soil should be scarified and properly
compacted for paving support. Paving recommendations are provided in Preliminary
Pavement Recommendations section of this report.
8.2 Soil Characteristics
8.2.1 The in-situ soils can be excavated with moderate effort using conventional excavation
equipment. Some caving should be anticipated in unshored excavations, especially where
granular soils are present.
8.2.2 It is the responsibility of the contractor to ensure that all excavations and trenches are properly
shored and maintained in accordance with applicable OSHA rules and regulations to maintain
safety and maintain the stability of existing adjacent improvements.
8.2.3 Onsite excavations must be conducted in such a manner that potential surcharges from
existing structures, construction equipment, and vehicle loads are resisted. The surcharge
area may be defined by a 1:1 projection down and away from the bottom of an existing
foundation or vehicle load. Penetrations below this 1:1 projection will require special
excavation measures such as sloping, shoring, or slot cutting. Excavation recommendations
are provided in the Temporary Excavations section of this report.
Geocon Project No. T2719-22-02 - 12 - February 22, 2022
8.2.4 The upper 5 feet of site soils encountered in the field investigation are considered to be
“Non-Expansive” (very low Expansion Index [EI] of 20 or less based on ASTM D4829,
See Figure B-3) as defined by 2019 California Building Code (CBC) Section 1803.5.3.
Table 8.2.4 presents soil classifications based on the EI. Recommendations presented herein
assume that the building foundations and slabs will derive support in these materials
TABLE 8.2.4
SOIL CLASSIFICATION BASED ON EXPANSION INDEX
Expansion Index (EI) Expansion Classification 2019 CBC Expansion Classification
0 – 20 Very Low Non-Expansive
21 – 50 Low
Expansive 51 – 90 Medium
91 – 130 High
Greater Than 130 Very High
8.3 Minimum Resistivity, pH, and Water-Soluble Sulfate
8.3.1 Potential of Hydrogen (pH) and resistivity testing as well as chloride content testing were
performed on a representative sample of soil to generally evaluate the corrosion potential to
surface utilities. The tests were performed in accordance with California Test Method
Nos. 643 and 422 and indicate that the soils are not considered a corrosive environment in
accordance with Caltrans corrosion criteria (Caltrans, 20 21). The results are presented in
Appendix B and should be considered for design of underground structures.
8.3.2 Laboratory tests were performed on representative samples of the site materials to measure
the percentage of water-soluble sulfate content. Results from the laboratory wat er-soluble
sulfate tests are presented in Appendix B and indicate that the on-site materials possess
“negligible” sulfate exposure to concrete structures as defined by 20 19 CBC Section 1904
and ACI 318-19 Chapter 19.
TABLE 8.3.2
REQUIREMENTS FOR CONCRETE
EXPOSED TO SULFATE-CONTAINING SOLUTIONS
Sulfate
Exposure
Exposure
Class
Water-Soluble
Sulfate
Percent
by Weight
Cement
Type
Maximum
Water to
Cement Ratio
by Weight
Minimum
Compressive
Strength (psi)
Negligible S0 0.00-0.10 -- -- 2,500
Moderate S1 0.10-0.20 II 0.50 4,000
Severe S2 0.20-2.00 V 0.45 4,500
Very Severe S3 > 2.00 V+ Pozzolan
or Slag 0.45 4,500
Geocon Project No. T2719-22-02 - 13 - February 22, 2022
8.3.3 Geocon West, Inc. does not practice in the field of corrosion engineering and mitigation.
If corrosion sensitive improvements are planned, it is recommended that a corrosion engineer
be retained to evaluate corrosion test results and incorporate the necessary precautions to avoid
premature corrosion.
8.4 Grading
8.4.1 Grading is anticipated to include preparation of building pads, excavation of site soils for
proposed foundations, utility trenches, and placement of backfill for ut ility trenches.
8.4.2 Earthwork should be observed, and compacted fill tested by representatives of Geocon.
The existing fill encountered during exploration is suitable for re -use as an engineered fill,
provided any encountered oversize material (greater than 6 inches) and any encountered
deleterious debris is removed.
8.4.3 A preconstruction conference should be held at the site prior to the beginning of grading
operations with the owner, contractor, civil engineer, geotechnical engineer, and, if applicable,
building official in attendance. Special soil handling requirements can be discussed at that
time.
8.4.4 Grading should commence with the removal of existing vegetation, improvements, and
undocumented fill, and previous fault trench backfill from the area to be graded. Deleterious
debris such as wood and root structures should be exported from the site and should not be
mixed with the fill soils. Asphalt and concrete should not be mixed with the fill soils unless
approved by the Geotechnical Engineer. Existing underground improvements planned for
removal should be excavated and the resulting depressions properly backfilled in accordance
with the procedures described herein. Once a clean excavation bottom has been established
it must be observed and approved in writing by the Geotechnical Engineer.
8.4.5 As a minimum, we recommend that the undocumented fill and /or the upper 8 to 12 feet of
existing site soils within the propos ed building footprint areas be excavated and properly
compacted for foundation and slab support. Deeper excavations should be conducted as
necessary to remove deeper artificial fill or soft alluvial or lacustrine soil at the direction of
the Geotechnical Engineer. The excavation should extend laterally a minimum distance
equal to the depth of the over excavation beyond the building footprint area, including
building appurtenances, or a distance equal to the depth of fill below the foundation,
whichever is greater. Proposed foundations should be underlain by at least 3 feet of newly
compacted engineered fill. The limits of existing fill and/or soft alluvial soils removal will
be verified by the Geocon representative during site grading activities .
Geocon Project No. T2719-22-02 - 14 - February 22, 2022
8.4.6 Excavations must be observed and approved in writing by the Geotechnical Engineer. Prior to
placing fill, the excavation bottom must be proof-rolled with heavy equipment in the presence
of the Geotechnical Engineer.
8.4.7 Where relatively loose or soft soils are encountered in the site excavation walls and bottom,
subgrade stabilization may be required prior to placing fill or installing utilities.
Where required, subgrade stabilization can be achieved by over excavating the loose or s oft
materials and replacing with compacted fill, placing 3- to 6-inch diameter rock in the soft
bottom and working it into soil until it is stabilized, or placing gravel wrapped in filter fabric
at the bottom of the excavation. Where used, gravel should consist of 12 to 18 inches of washed
angular ¾ inch gravel atop a filter fabric (Mirafi 500X or equivalent) on the excavation bottom.
The filter fabric should be placed in a manner so that the gravel does not have direct contact
with the soil. Once the gravel is placed and vibrated to a relatively dense state a top layer of
filter fabric should be placed to cover the gravel. Recommendations for stabilizing excavation
bottoms should be based on an evaluation in the field by Geocon at the time of construction.
8.4.8 We expect that stable excavations can be achieved with sloping measures. Excavation
recommendations are provided in the Temporary Excavations section of this report.
8.4.9 Fill and backfill soils should be placed in horizontal loose layers approximately 6 to
8 inches thick, moisture conditioned to near optimum moisture content, and properly
compacted to a minimum 90 percent of the maximum dry density per ASTM D 1557 (latest
edition).
8.4.10 Where new paving is to be placed, we recommend that undocumented fill and soft
native soils be excavated and properly compacted for paving support. The client should be
aware that excavation and compaction of undocumented fi ll and soft soils in the area of new
paving is not required; however, paving constructed over existing un documented fill or
unsuitable alluvial or lacustrine soil may experience increased settlement and/or cracking,
and may therefore have a shorter design life and increased maintenance costs. As a
minimum, the upper 24 inches of soil should consist of properly compacted fill as described
in Section 8.4.9. The upper 12 inches of subgrade in pavement areas should be moisture
conditioned and compacted to at least 95 percent relative compaction near optimum moisture
content. Paving recommendations are provided in Preliminary Pavement Recommendations
section of this report.
8.4.11 Imported fill shall be observed, tested, and approved by Geocon prior to bringing soil to the
site. Rocks larger than 6 inches in diameter shall not be used in the fill. If necessary, import
soils used as structural fill should have an expansion index less than 20 and corrosivity
properties that are equally or less detrimental to that of the existing onsite soils. If import soils
will be utilized in the building pad, the soils must be placed uniformly and at equal thickness
at the direction of the Geotechnical Engineer. Soils can be borrowed from non-building pad
areas and later replaced with imported soils.
Geocon Project No. T2719-22-02 - 15 - February 22, 2022
8.4.12 If import soils will be utilized, the soils must be placed uniformly and at equal thickness at the
direction of the Geotechnical Engineer (a representative of Geocon West, Inc.). Soils can be
borrowed from non-building pad areas and later replaced with imported soils.
8.4.13 Trench and foundation excavation bottoms must be observed and approved in writing by the
Geotechnical Engineer prior to placing bedding materials, fill, steel, gravel, or concrete.
8.5 Earthwork Grading Factors
8.5.1 Estimates of shrinkage factors are based on empirical judgments comparing the material in its
existing or natural state as encountered in the exploratory excavations to a compacted state.
Variations in natural soil density and in compacted fill density render shrinkage value
estimates very approximate. As an example, the contractor can compact the fill to a dry density
of 90 percent or higher of the laboratory maximum dry density. Thus, the contractor has an
approximately 10 percent range of control over the fill volume. Due to the variations in the
actual shrinkage/bulking factors, a balance area should be provided to accommodate
variations.
8.6 Utility Trench Backfill
8.6.1 Utility trenches should be properly backfilled in accordance with the requirements of the latest
edition of the Standard Specifications for Public Works Construction (Greenbook) and
applicable agency requirements. The pipes should be bedded with well-graded crushed rock
or clean sand (Sand Equivalent greater than 30) to a depth of at least one foot over the pipe.
8.6.2 If open graded rock is used, it should be wrapped in filter fabric to prevent finer soils from
migrating into the rock voids. The remainder of the trench backfill may be derived from onsite
soil or approved import soil. Backfill of utility trenches should not contain rocks greater than
3 inches in diameter. The use of 2-sack slurry and controlled low strength material (CLSM)
are also acceptable as backfill. However, consideration should be given to the possibility of
differential settlement where the slurry ends and earthen backfill begins. These transitions
should be minimized, and additional stabilization should be considered at these transitions.
8.6.3 Utility trench backfill should be placed in layers no thicker than will allow for adequate
bonding and compaction. Utility backfill should be compacted to a dry density of at least
90 percent of the laboratory maximum dry density and moisture conditioned at or slightly
above optimum moisture content (as determined by ASTM D1557). Backfill at the finish
subgrade elevation of new pavements should be compacted to at least 95 percent of the
maximum dry density. Backfill materials placed below the recommended moisture content
may require additional moisture conditioning prior to placing additional fill.
Geocon Project No. T2719-22-02 - 16 - February 22, 2022
8.7 Seismic Design Criteria
8.7.1 Table 8.7.1 summarizes site-specific design criteria obtained from the 2019 California
Building Code (CBC; Based on the 2018 International Building Code [IBC] and ASCE
7-16), Chapter 16 Structural Design, Section 1613 Earthquake Loads. We used the computer
program Seismic Design Maps, provided by the Structural Engineers Association (SEA) to
calculate the seismic design parameters. The short spectral response uses a period of
0.2 second. We evaluated the Site Class based on the discussion in Section 1613.2.2 of the
2019 CBC and Table 20.3-1 of ASCE 7-16. Although the site is liquefiable, we expect the
planned structures will have a period of ½ second or less and therefore can be classified as Site
Class D. The values presented herein are for the risk-targeted maximum considered
earthquake (MCER).
TABLE 8.7.1
2019 CBC SEISMIC DESIGN PARAMETERS
Parameter Value 2019 CBC Reference
Site Class D Section 1613.3.2
MCER Ground Motion Spectral
Response Acceleration – Class B (short), SS 1.855g Figure 1613.3.1(1)
MCER Ground Motion Spectral
Response Acceleration – Class B (1 sec), S1 0.673g Figure 1613.3.1(2)
Site Coefficient, FA 1 Table 1613.3.3(1)
Site Coefficient, FV 1.7* Table 1613.3.3(2)
Site Class Modified MCER
Spectral Response Acceleration (short), SMS 1.855g Section 1613.3.3 (Eqn 16-
37)
Site Class Modified MCER
Spectral Response Acceleration (1 sec), SM1 1.144g* Section 1613.3.3 (Eqn 16-
38)
5% Damped Design
Spectral Response Acceleration (short), SDS 1.237g Section 1613.3.4 (Eqn 16-
39)
5% Damped Design
Spectral Response Acceleration (1 sec), SD1 0.763g* Section 1613.3.4 (Eqn 16-
40)
Note: Per Section 11.4.8 of ASCE/SEI 7-16, a ground motion hazard analysis shall be performed
for projects for Site Class “E” sites with Ss greater than or equal to 1.0g and for Site Class “D”
and “E” sites with S1 greater than 0.2g. Section 11.4.8 also provides exceptions which indicates
that the ground motion hazard analysis may be waived provided the exceptions are followed.
Using the code based values presented in the table above, in lieu of performing a ground motion
hazard analysis, requires the exceptions outlined in ASCE 7-16 Section 11.4.8 be followed.
*See Section 11.4.8
Geocon Project No. T2719-22-02 - 17 - February 22, 2022
8.7.2 Table 8.7.2 presents additional seismic design parameters for projects located in Seismic
Design Categories of D through F in accordance with ASCE 7-16 for the mapped maximum
considered geometric mean (MCEG).
TABLE 8.7.2
ASCE 7-16 PEAK GROUND ACCELERATION
Parameter Value ASCE 7-16 Reference
Site Class D Section 1613.2.2 (2019 CBC)
Mapped MCEG Peak Ground
Acceleration, PGA 0.797g Figure 22-9
Site Coefficient, FPGA 1.1 Table 11.8-1
Site Class Modified MCEG Peak Ground
Acceleration, PGAM 0.877g Section 11.8.3 (Eqn 11.8-1)
8.7.3 Conformance to the criteria in Tables 8.7.1 and 8.7.2 for seismic design does not constitute
any kind of guarantee or assurance that significant structural damage or ground failure will not
occur if a large earthquake occurs. The primary goal of seismic design is to protect life, not to
avoid all damage, since such design may be economically prohibitive.
8.7.4 The Maximum Considered Earthquake Ground Motion (MCE) is the level of ground motion
that has a 2 percent chance of exceedance in 50 years, with a statistical return period of
2,475 years. According to the 2019 California Building Code and ASCE 7-16, the MCE is to
be utilized for the evaluation of liquefaction, lateral spreading, seismic settlements, and it is
our understanding that the intent of the building code is to maintain “Life Safety” during an
MCE event. The Design Earthquake
8.7.5 Ground Motion (DE) is the level of ground motion that has a 10 percent chance of exceedance
in 50 years, with a statistical return period of 475 years.
8.7.6 Deaggregation of the MCE peak ground acceleration was performed using the USGS online
Unified Hazard Tool, 2014 Conterminous U.S. Dynamic edition (v4.2.0). The result of the
deaggregation analysis indicates that the predominant earthquake contributing to t he MCE
peak ground acceleration is characterized as a 7.71 magnitude event occurring at a
hypocentral distance of 2.1 kilometers from the site.
8.7.7 Deaggregation was also performed for the Design Earthquake (DE) peak ground acceleration,
and the result of the analysis indicates that the predominant earthquake contributing to the DE
peak ground acceleration is characterized as a 6.49 magnitude occurring at a hypocentral distance
of 6.85 kilometers from the site.
Geocon Project No. T2719-22-02 - 18 - February 22, 2022
8.7.8 Conformance to the criteria in the above tables for seismic design does not constitute any kind
of guarantee or assurance that significant structural damage or ground failure will not occur if
a large earthquake occurs. The primary goal of seismic design is to protect life, not to avoid
all damage, since such design may be economically prohibitive.
8.8 Mat Foundation
8.8.1 Subsequent to the recommended grading, a mat foundation system may be utilized for
support of the proposed structure provided foundations derive support on a blanket of newly
placed engineered fill. Proposed foundations should be underlain by at least 3 feet of newly
compacted engineered fill.
8.8.2 We expect that the mat foundation will impart an average pressure of less than
1,000 pounds per square foot (psf), with locally higher pressures up to 3,000 psf.
The recommended maximum allowable bearing value is 3,000 psf. The allowable bearing
pressure may be increased by up to one-third for transient loads due to wind or seismic forces.
8.8.3 A modulus of subgrade reaction of 100 to 150 pounds per cubic inch (pci) may be used in the
design of mat foundations deriving support in newly placed engineered fill. This value is a unit
value for use with a one-foot square footing. The modulus should be reduced in accordance
with the following equation when used with larger foundations:
K R =K [B+1
2B ]
2
where: KR = reduced subgrade modulus
K = unit subgrade modulus
B = foundation width (in feet)
8.8.4 The thickness of and reinforcement for the mat foundation should be designed by the project
structural engineer.
8.8.5 No special subgrade presaturation is required prior to placement o f concrete. However,
the slab and foundation subgrade should be sprinkled as necessary; to maintain a moist
condition as would be expected in any concrete placement.
8.8.6 For seismic design purposes, a coefficient of f riction of 0.40 may be utilized between
the concrete mat and newly placed engineered fill, and 0.15 for slabs underlain by a
moisture barrier.
Geocon Project No. T2719-22-02 - 19 - February 22, 2022
8.8.7 Foundation excavations should be observed by the Geotechnical Engineer, prior to the
placement of reinforcing steel and concrete to verify that the exposed soil conditions are
consistent with those anticipated. If unanticipated soil conditions are encountered, foundation
modifications may be required.
8.8.8 This office should be provided a copy of the final construction plans so that the excavation
recommendations presented herein could be properly reviewed and revised if necessary.
8.9 Foundation Settlement
8.9.1 The enclosed liquefaction analysis indicates that the alluvial soils could be prone to up to
3 inches of liquefaction settlement as a result of the Design Earthquake ground motion.
The resulting differential settlement at the ground surface is anticipated to b e up to
approximately 1.5 inches over a horizontal distance of 50 feet. These settlements are in
addition to the static settlements indicated below and must be considered in the structural
design.
8.9.2 The maximum expected static settlement f or the structures supported on a mat foundation
system deriving support in newly compacted engineered fill and utilizing a n average bearing
pressure of 1,000 psf is estimated to be less than 0.75 inch and occur below the heaviest
loaded structural element. Settlement of the foundation system is expected to occur on initial
application of loading. Differential settlement is not expected to exceed 0.5 inch over a
distance of 40 feet.
8.9.3 Based on seismic considerations, the proposed structure supported on a mat foundation system
should be designed for a combined static and seismically induced differential settlement of
less than 1.25 inch over a distance of 40 feet.
8.9.4 Once the design and foundation loading configurations for the proposed structures proceeds
to a more finalized plan, the estimated settlements presented in this report should be
reviewed and revised, if necessary. If the final foundation loading configurat ions are greater
than the assumed loading conditions, the potential for settlement should be reevaluated by
this office.
8.10 Lateral Design
8.10.1 Resistance to lateral loading may be provided by friction acting at the base of fou ndations,
slabs and by passive earth pressure. An allowable coefficient of friction of 0.40 may be
used with the dead load forces in the undisturbed alluvial soils and newly compacted
engineered fill.
Geocon Project No. T2719-22-02 - 20 - February 22, 2022
8.10.2 Passive earth pressure for the sides of foundations poured against undisturbed alluvium may
be computed as an equivalent fluid having a density of 300 pounds per cubic foot (pcf) with
a maximum earth pressure of 3,000 psf. When combining passive and friction for lateral
resistance, the passive component should be reduced by one -third.
8.11 Exterior Concrete Flatwork
8.11.1 Exterior concrete flatwork not subject to vehicular traffic should be constructed in accordance
with the recommendations presented in Table 8.11.1. The recommended steel reinforcement
would help reduce the potential for cracking.
TABLE 8.11.1
MINIMUM CONCRETE FLATWORK RECOMMENDATIONS
Expansion
Index, EI Minimum Steel Reinforcement* Options Minimum
Thickness
EI < 50 6x6-W2.9/W2.9 (6x6-6/6) welded wire mesh 4 Inches No. 3 Bars 18 inches on center, Both Directions
*In excess of 8 feet square.
8.11.2 The subgrade soil should be properly moisturized and compacted prior to the placement of
steel and concrete. The subgrade soil should be compacted to a dry density of at least
90 percent of the laboratory maximum dry density near to slightly above optimum moisture
content in accordance with ASTM D 1557.
8.11.3 Even with the incorporation of the recommendations of this report, the exterior concrete
flatwork has a potential to experience some uplift due to expansive soil beneath grade.
The steel reinforcement should overlap continuously in flatwork to reduce the potential for
vertical offsets within flatwork. Additionally, flatwork should be structurally connected to the
curbs, where possible, to reduce the potential for offsets between the curbs and the flatwork.
8.11.4 Concrete flatwork should be provided with crack control joints to reduce and/or control
shrinkage cracking. Crack control spacing should be determined by the project structural
engineer based upon the slab thickness and intended usage. Criteria of the American Concrete
Institute (ACI) should be taken into consideration when establishing crack control spacing.
Subgrade soil for exterior slabs not subjected to vehicle loads should be compacted in
accordance with criteria presented in the grading section prior to concrete placement. Subgrade
soil should be properly compacted and the moisture content of subgrade soil should be verified
prior to placing concrete. Base materials will not be required below concrete improvements.
Geocon Project No. T2719-22-02 - 21 - February 22, 2022
8.11.5 Where exterior flatwork abuts the structure at entrant or exit points, the exterior slab should
be dowelled into the structure’s foundation stemwall. This recommendation is intended to
reduce the potential for differential elevations that could result from differential settlement or
minor heave of the flatwork. Dowelling details should be designed by the project structural
engineer.
8.11.6 The recommendations presented herein are intended to reduce the potential for cracking of
exterior slabs as a result of differential movement. However, even with the incorporation of
the recommendations presented herein, slabs-on-grade will still crack. The occurrence of
concrete shrinkage cracks is independent of the soil supporting characteristics.
Their occurrence may be reduced and/or controlled by limiting the slump of the concrete, the
use of crack control joints and proper concrete placement and curing. Crack control joints
should be spaced at intervals no greater than 12 feet. Literature provided by the Portland
Concrete Association (PCA) and American Concrete Institute (ACI) present recommendations
for proper concrete mix, construction, and curing practices, and should be incorporated into
project construction.
8.12 Retaining Walls
8.12.1 The recommendations presented below are generally applicable to the design of rigid concrete
or masonry retaining walls having a maximum height of 6 feet. In the event that walls
significantly higher than 6 feet are planned, Geocon should be contacted for additional
recommendations.
8.12.2 Retaining walls with a level backfill surface that are not restrained at the top should be
designed utilizing a triangular distribution of pressure (active pressure) of 30 pcf.
8.12.3 Restrained walls are those that are not allowed to rotate more than 0.001H (where H equals
the height of the retaining portion of the wall in feet) at the top of the wall. Where walls are
restrained from movement at the top, walls may be designed utilizing a triangular distribution
of pressure (at-rest pressure) of 54 pcf.
8.12.4 The wall pressures provided above assume that the proposed retaining walls will support
relatively undisturbed alluvial soils or engineered fill derived from onsite soils. If import soil
will be used to backfill proposed retaining walls, revised earth pressures may be required to
account for the geotechnical properties of the import soil used as engineered fill. This should
be evaluated once the use of import soil is established. All imported fill shall be observed,
tested, and approved by Geocon West, Inc. prior to bringing soil to the site.
Geocon Project No. T2719-22-02 - 22 - February 22, 2022
8.12.5 The wall pressures provided above assume that the retaining wall will be properly drained
preventing the buildup of hydrostatic pressure. If retaining wall drainage is not implemented,
the equivalent fluid pressure to be used in design of undrained walls is 90 pcf. The value
includes hydrostatic pressures plus buoyant lateral earth pressures.
8.12.6 Additional active pressure should be added for a surcharge condition due to sloping ground,
vehicular traffic or adjacent structures and should be designed for each condition as the project
progresses. Once the design becomes more finalized, an addendum letter can be prepared
revising recommendations and addressing specific surcharge conditions throughout the
project, if necessary.
8.12.7 Retaining wall foundations may be supported on conventional foundations deriving support on
a minimum of 24 inches of newly placed engineered fill.
8.12.8 Retaining wall footings may be designed for an allowable bearing capacity of 2,500 psf, and
should be a minimum of 12 inches in width and 18 inches in depth below the lowest adjacent
grade.
8.12.9 The soil bearing pressure above may be increased by 250 psf and 500 psf for each additional
foot of foundation width and depth, respectively, up to a maximum allowable soil bearing
pressure of 3,000 psf. The allowable bearing pressure may be increased by one-third for
transient loads due to wind or seismic forces.
8.12.10 Reinforcement for retaining wall footings should be designed by the project structural
engineer.
8.12.11 The above foundation dimensions and minimum reinforcement recommendations are based
on soil conditions and building code requirements only, and are not intended to be used in lieu
of those required for structural purposes.
8.12.12 Foundation excavations should be observed and approved in writing by the Geotechnical
Engineer (a representative of Geocon West, Inc.), prior to the placement of reinforcing steel
and concrete to verify that the exposed soil conditions are consistent with those anticipated. If
unanticipated soil conditions are encountered, foundation modifications may be required.
8.12.13 Retaining walls should be designed to ensure stability against overturning sliding, and
excessive foundation pressure. Where a keyway is extended below the wall base with the intent
to engage passive pressure and enhance sliding stability, it is not necessary to consider active
pressure on the keyway.
Geocon Project No. T2719-22-02 - 23 - February 22, 2022
8.12.14 Drainage openings through the base of the wall (weep holes) should not be used where the
seepage could be a nuisance or otherwise adversely affect the property adjacent to the base of
the wall. The recommendations herein assume a properly compacted granular (EI of 50 or less)
free-draining backfill material with no hydrostatic forces or imposed surcharge load. The
retaining wall should be properly drained as shown in the Typical Retaining Wall Drainage
Detail. If conditions different than those described are expected, or if specific drainage details
are desired, Geocon should be contacted for additional recommendations.
Typical Retaining Wall Drainage Detail
8.13 Preliminary Pavement Recommendations
8.13.1 We calculated the flexible pavement sections in general conformance with the Caltrans
Method of Flexible Pavement Design (Highway Design Manual, Section 608.4) using an
estimated Traffic Index (TI) of 5.0, 5.5, 6.0, and 7.0 for parking stalls, driveways, medium
truck traffic areas, and heavy truck traffic areas, respectively. The project civil engineer and
owner should review the pavement designations to determine appropriate locations for
pavement thickness. The final pavement sections for the parking lot should be based on the R-
Value of the subgrade soil encountered at final subgrade elevation. We have assumed an
R-Value of 20 and 78 for the subgrade soil and base materials, respectively, for the purposes
of this preliminary analysis. Table 8.13.1 presents the preliminary flexible pavement sections.
TABLE 8.13.1
PRELIMINARY FLEXIBLE PAVEMENT SECTION
Location
Assumed
Traffic
Index
Assumed
Subgrade
R-Value
Asphalt
Concrete
(inches)
Class 2
Aggregate
Base (inches)
Parking stalls for automobiles
and light-duty vehicles 5.0 20 3 7
Driveways for automobiles
and light-duty vehicles 5.5 20 3 9
Medium truck traffic areas 6.0 20 3.5 10
Driveways for heavy truck traffic 7.0 20 4 12
Geocon Project No. T2719-22-02 - 24 - February 22, 2022
8.13.2 Prior to placing base materials, the upper 12 inches of the subgrade soil should be scarified,
moisture conditioned as necessary, and recompacted to a dry density of at least 95 percent of
the laboratory maximum dry density near to slightly above optimum moisture content as
determined by ASTM D 1557. Similarly, the base material should be compacted to a dry
density of at least 95 percent of the laboratory maximum dry density near to slightly above
optimum moisture content. Asphalt concrete should be compacted to a density of at least
95 percent of the laboratory Hveem density in accordance with ASTM D 2726.
8.13.3 Base materials should conform to Section 26-1.02B of the Standard Specifications for
The State of California Department of Transportation (Caltrans) with a ¾-inch maximum size
aggregate. Asphalt concrete should conform to Section 203-6 of the Standard Specifications
for Public Works Construction (Greenbook).
8.13.4 The base thickness can be reduced if a reinforcement geogrid is used during the installation of
the pavement. Geocon should be contact for additional recommendations if alternate design
parameters are requested.
8.13.5 A rigid Portland cement concrete (PCC) pavement section should be placed in heavy truck
areas, driveway aprons, and cross gutters. We calculated the rigid pavement section in general
conformance with the procedure recommended by the American Concrete Institute report ACI
330R Guide for Design and Construction of Concrete Parking Lots using the parameters
presented in Table 8.13.5.
TABLE 8.13.5
RIGID PAVEMENT DESIGN PARAMETERS
Design Parameter Design Value
Modulus of subgrade reaction, k 150 pci
Modulus of rupture for concrete, MR 500 psi
Traffic Category, TC C and D
Average daily truck traffic, ADTT 100 and 700
Geocon Project No. T2719-22-02 - 25 - February 22, 2022
8.13.6 Based on the criteria presented herein, the PCC pavement sections should have a minimum
thickness as presented in Table 8.13.6.
TABLE 8.13.6
RIGID PAVEMENT RECOMMENDATIONS
Location Portland Cement Concrete (inches)
Automobile Parking Stalls (TC=C) 6.5
Heavy Truck and Fire Lane Areas (TC=D) 7.5
8.13.7 The PCC pavement should be placed over subgrade soil that is compacted to a dry density of
at least 95 percent of the laboratory maximum dry density at near optimum moisture content.
This pavement section is based on a minimum concrete compressive strength of approximately
3,000 psi (pounds per square inch).
8.13.8 A thickened edge or integral curb should be constructed on the outside of concrete slabs
subjected to wheel loads. The thickened edge should be 1.2 times the slab thickness or a
minimum thickness of 2 inches, whichever results in a thicker edge, and taper back to
the recommended slab thickness 4 feet behind the face of the slab (e.g., 6-inch and
7.5-inch-thick slabs would have an 8- and 9.5-inch-thick edge, respectively). Reinforcing steel
will not be necessary within the concrete for geotechnical purposes with the possible exception
of dowels at construction joints as discussed herein.
8.13.9 In order to control the location and spread of concrete shrinkage cracks, crack-control joints
(weakened plane joints) should be included in the design of the concrete pavement slab in
accordance with the referenced ACI report.
8.13.10 The performance of pavements is highly dependent on providing positive surface drainage
away from the edge of the pavement. Ponding of water on or adjacent to the pavement surfaces
will likely result in pavement distress and subgrade failure. Drainage from landscaped areas
should be directed to controlled drainage structures. Landscape areas adjacent to the edge of
asphalt pavements are not recommended due to the potential for surface or irrigation water to
infiltrate the underlying permeable aggregate base and cause distress. Where such a condition
cannot be avoided, consideration should be given to incorporating measures that will
significantly reduce the potential for subsurface water migration into the aggregate base. If
planter islands are planned, the perimeter curb should extend at least 6 inches below the level
of the base materials.
Geocon Project No. T2719-22-02 - 26 - February 22, 2022
8.14 Temporary Excavations
8.14.1 The recommendations included herein are provided for temporary excavations. It is the
responsibility of the contractor to provide a safe excavation during the construction of the
proposed project.
8.14.2 Excavations of up to 12 feet in vertical height are expected during grading operations and
utility installation. The contractor’s competent person should evaluate the necessity for lay
back of vertical cut areas. Vertical excavations up to 5 feet may be attempted where loose soils
or caving sands are not present, and where not surcharged by existing structures or
vehicle/construction equipment loads.
8.14.3 Vertical excavations greater than 5 feet will require sloping measures in order to provide a
stable excavation. Where sufficient space is available, temporary unsurcharged embankments
should be designed by the contractor’s competent person in accordance with OSHA
regulations.
8.14.4 Where sufficient space is available, temporary unsurcharged embankments in soil may be
sloped back at a uniform 1.5:1 (h:v) slope gradient or flatter. Excavations in bedrock may be
steepened per Cal OSHA requirements. Note, a uniform slope does not have a vertical portion.
8.14.5 Where there is insufficient space for sloped excavations, shoring or trench shields should be
used to support excavations. Shoring may also be necessary where sloped excavation could
remove vertical or lateral support of existing improvements, including existing utilities and
adjacent structures. Recommendations for temporary shoring can be provided in an addendum
if needed.
8.14.6 Where temporary constructions slopes are utilized, the top of the slope should be barricaded
to prevent vehicles and storage loads at the top of the slope within a horizontal distance equal
to the height of the slope. If the temporary construction slopes are to be maintained during the
rainy season, berms are suggested along the tops of the slopes where necessary to prevent
runoff water from entering the excavation and eroding the slope faces. The contractor’s
personnel should inspect the soil exposed in the cut slopes during excavation in accordance
with OSHA regulations so that modifications of the slopes can be made if variations in the soil
conditions occur. Excavations should be stabilized within 30 days of initial excavation.
Geocon Project No. T2719-22-02 - 27 - February 22, 2022
8.15 Site Drainage and Moisture Protection
8.15.1 Adequate site drainage is critical to reduce the potential for differential soil movement, erosion
and subsurface seepage. Under no circumstances should water be allowed to pond adjacent to
footings. The site should be graded and maintained such that surface drainage is directed away
from structures in accordance with 2019 CBC 1804.4 or other applicable standards. In
addition, surface drainage should be directed away from the top of slopes into swales or other
controlled drainage devices. Roof and pavement drainage should be directed into conduits that
carry runoff away from the proposed structure.
8.15.2 Underground utilities should be leak free. Utility and irrigation lines should be checked
periodically for leaks and detected leaks should be repaired promptly. Detrimental soil
movement could occur if water can infiltrate the soil for prolonged periods of time.
8.15.3 Storm water mitigation systems should be offset a minimum of 20 feet from the outside edge
of structural footings, so as to reduce the occurrence of water migrating within the structures’
load projection.
8.15.4 Landscaping planters adjacent to paved areas are not recommended due to the potential for
surface or irrigation water to infiltrate the pavement’s subgrade and base course.
We recommend that area drains to collect excess irrigation water and transmit it to drainage
structures or impervious above-grade planter boxes be used. In addition, where landscaping is
planned adjacent to the pavement, we recommend construction of a cutoff wall or the use of
an impermeable geosynthetic along the edge of the pavement that extends at least 6 inches
below the bottom of the base material.
8.15.5 If not properly constructed, there is a potential for distress to improvements and properties
located hydrologically down gradient or adjacent to infiltration areas. Factors such as the
amount of water to be detained, its residence time, and soil permeability have an important
effect on seepage transmission and the potential adverse impacts that may occur if the storm
water management features are not properly designed and constructed. We have not performed
a hydrogeology study at the site. Downgradient and adjacent structures may be subjected to
seeps, movement of foundations and slabs, or other impacts as a result of water infiltration.
8.16 Grading and Foundation Plan Review
8.16.1 Geocon should review the project grading and foundation plans prior to final design submittal
to verify that the plans have been prepared in substantial conformance with the recommendations
of this report and to provide additional analyses or recommendations, if necessary.
Geocon Project No. T2719-22-02 February 22, 2022
LIMITATIONS AND UNIFORMITY OF CONDITIONS
The recommendations of this report pertain only to the site investigated and are based upon the
assumption that the soil conditions do not deviate from those disclosed in this investigation. If any
variations or undesirable conditions are encountered during construction, or if the proposed construction
will differ from that expected herein, Geocon West, Inc. should be notified so that supplemental
recommendations can be given. The evaluation or identification of the potential presence of hazardous
materials was not part of the scope of services provided by Geocon West, Inc.
This report is issued with the understanding that it is the responsibility of the owner, or of their
representative, to ensure that the information and recommendations contained herein are brought to the
attention of the architect and engineer for the project and incorporated into the plans, and the necessary
steps are taken to see that the contractor and subcontractors carry out such recommendations in the field.
The requirements for concrete and steel reinforcement presented in this report are preliminary
recommendations from a geotechnical perspective. The Structural Engineer should provide the final
recommendations for structural design of concrete and steel reinforcement for foundation systems, floor
slabs, exterior concrete, or other systems where concrete and steel reinforcement are utilized, in
accordance with the latest version of applicable codes.
The findings of this report are valid as of the date of this report. However, changes in the conditions of
a property can occur with the passage of time, whether they are due to natural processes or the works of
man on this or adjacent properties. In addition, changes in applicable or appropriate standards may occur,
whether they result from legislation or the broadening of knowledge . Accordingly, the findings of this
report may be invalidated wholly or partially by changes outside our control . Therefore, this report is
subject to review and should not be relied upon after a period of three years.
The firm that performed the geotechnical investigation for the project should be retained to provide
testing and observation services during construction to provide continuity of geotechnical interpretation
and to check that the recommendations presented for geotechnical aspects of site development are
incorporated during site grading, construction of improvements, and excavation of foundations .
If another geotechnical firm is selected to perform the testing and observatio n services during
construction operations, that firm should prepare a letter indicating their intent to assume the
responsibilities of project Geotechnical Engineer of Record. A copy of the letter should be provided to
the regulatory agency for their records. In addition, that firm should provide revised recommendations
concerning the geotechnical aspects of the proposed development, or a written acknowledgement of their
concurrence with the recommendations presented in our report. They should also perform additional
analyses deemed necessary to assume the role of Geotechnical Engineer of Record.
Geocon Project No. T2719-22-02 - 1 - February 22, 2022
LIST OF REFERENCES
1. American Concrete Institute, 2011, Building Code Requirements for Structural Concrete,
Report by ACI Committee 318.
2. American Concrete Institute, 2008, Guide for Design and Construction of Concrete Parking
Lots, Report by ACI Committee 330.
3. ASCE 7-16, 2019, Minimum Design Loads for Buildings and Other Structures.
4. California Building Standards Commission, 2019, California Building Code (CBC), California
Code of Regulations Title 24, Part 2.
5. California Department of Transportation (Caltrans), 2021, Division of Engineering Services,
Materials Engineering and Testing Services, Corrosion Guidelines, Version 3.2,
dated May.
6. California Department of Water Resources, Water Data Library website,
https://wdl.water.ca.gov/ ; accessed February 2022.
7. California Geological Survey (CGS), 2003, Earthquake Shaking Potential for California,
from USGS/CGS Seismic Hazards Model, CSSC No. 03-02
8. California Geologic Survey, 2008, Special Publication 117A, Guidelines for Evaluating and
Mitigating Seismic Hazards in California, Revised and Re-adopted September 11.
9. Morton, D.M. and F.H. Weber, Jr., 2003, Preliminary Geologic Map of the Elsinore 7.5’
Quadrangle, Riverside County, California, USGS Open-File Report 03-281, version 1.0, Scale
1:24,000.
10. Google Earth Pro, 2021, accessed February 2022.
11. Harden, Deborah R., 1998, California Geology, Prentice Hall Publishing.
12. Jennings, C. W., 2010, California Division of Mines and Geology, Fault Activity Map of
California and Adjacent Areas, California Geologic Data Map Series Map No. 6.
13. Legg, M. R., J. C. Borrero, and C. E. Synolakis, Evaluation of Tsunami Risk to Southern
California Coastal Cities, 2002 NEHRP Professional Fellowship Report, dated January 2003.
14. OSPD, 2018, Seismic Design Maps, https://seismicmaps.org Accessed February 2022.
15. Public Works Standards, Inc., 2021, Standard Specifications for Public Works Construction
“Greenbook,” Published by BNi Building News.
16. Riverside County, Map My County, accessed February 2022.
17. Riverside County Flood Control and Water Conservation District, 2011, Design Handbook for
Low Impact Development Best Management Practices, dated September.
SOURCE: CGS, 1980, Elsinore AP Quadrangle.
VICINITY MAP
GRAND AVE. AT KATHRYN WAY
LAKE ELSINORE, CALIFORNIA
FEB. 2022 PROJECT NO. T2719-22-02 FIG. 1
1 INCH = 1500 FEET
(SCALE IS APPROXIMATE)
AMO
Lake
Elsinore
Project
Site
PROJECT NO. T2719-22-02 FIG. 2
APN 371.150.001 & 371.150.002
GRAND AVENUE AT KATHRYN WAY
LAKE ELSINORE, CALIFORNIA
GEOLOGIC MAP
GEOCON LEGEND
……. PROJECT LIMITS
Locations are approximate
……. GEOTECHNICAL BORING LOCATION, 2016
SOURCE: Grant Becklund Civil Engineer, 2022, Preliminary Grading Plan PA 2021-19, dated January.
0 25’50’
SCALE: 1” = 25’
B-10
……. PERCOLATION TEST LOCATION
P-4
……... UNDOCUMENTED FILL afu
……... ALLUVIAL FAN DEPOSITSQyf
FEBRUARY 2022LCW
12 ……. ESTIMATED REMOVAL DEPTH (ft)
……... GEOLOGIC CONTACT
afu
B-3
B-4
B-1
B-2
B-10 B-6
1212
10-12
B-5
88
8
8
P-3P-1 P-2
P-4
Willard Fault with building setback zone
afu
Qyf
Figure 3
Client :Lake Resort Apartments
File No. :T2719-22-02
Boring :1
EMPIRICAL ESTIMATION OF LIQUEFACTION POTENTIAL
DESIGN EARTHQUAKE
NCEER (1996) METHOD By Thomas F. Blake (1994-1996)
EARTHQUAKE INFORMATION:ENERGY & ROD CORRECTIONS:
Earthquake Magnitude:6.49 Energy Correction (CE) for N60:1.25
Peak Horiz. Acceleration PGAM (g):0.877 Rod Len.Corr.(CR)(0-no or 1-yes):1.0
2/3 PGAM (g):0.585 Bore Dia. Corr. (CB):1.15
Calculated Mag.Wtg.Factor:0.694 Sampler Corr. (CS):1.20
Historic High Groundwater:5.0 Use Ksigma (0 or 1):1.0
Groundwater Depth During Exploration:26.5
LIQUEFACTION CALCULATIONS:
Unit Wt. Water (pcf):62.4
Depth to Total Unit Water FIELD Depth of Liq.Sus.-200 Est. Dr CN Corrected Eff. Unit Resist.rd Induced Liquefac.
Base (ft)Wt. (pcf)(0 or 1)SPT (N)SPT (ft)(0 or 1)(%)(%)Factor (N1)60 Wt. (psf)CRR Factor CSR Safe.Fact.
1.0 125.0 0 19.0 5.0 1 95 2.000 49.2 125.0 Infin.0.998 0.263 --
2.0 125.0 0 19.0 5.0 1 95 2.000 49.2 125.0 Infin.0.993 0.262 --
3.0 125.0 0 19.0 5.0 1 95 2.000 49.2 125.0 Infin.0.989 0.261 --
4.0 125.0 0 19.0 5.0 1 95 2.000 49.2 125.0 Infin.0.984 0.260 --
5.0 125.0 1 19.0 5.0 1 95 1.927 47.4 62.6 Infin.0.979 0.274 Non-Liq.
6.0 125.0 1 19.0 5.0 1 95 1.743 42.8 62.6 Infin.0.975 0.298 Non-Liq.
7.0 125.0 1 12.0 7.5 1 36 73 1.603 31.9 62.6 Infin.0.970 0.317 Non-Liq.
8.0 125.0 1 12.0 7.5 1 36 73 1.492 30.2 62.6 Infin.0.966 0.332 Non-Liq.
9.0 125.0 1 12.0 7.5 1 36 73 1.402 28.8 62.6 0.375 0.961 0.345 1.09
10.0 125.0 1 12.0 7.5 1 36 73 1.326 27.6 62.6 0.338 0.957 0.355 0.95
11.0 125.0 1 12.0 7.5 1 36 73 1.261 26.6 62.6 0.315 0.952 0.364 0.87
12.0 125.0 1 6.0 12.5 1 36 49 1.205 16.4 62.6 0.178 0.947 0.371 0.48
13.0 125.0 1 6.0 12.5 1 36 49 1.156 16.0 62.6 0.174 0.943 0.377 0.46
14.0 125.0 1 6.0 12.5 1 36 49 1.112 15.6 62.6 0.170 0.938 0.382 0.45
15.0 125.0 1 10.0 17.5 1 42 60 1.073 22.8 62.6 0.253 0.934 0.386 0.66
16.0 125.0 1 10.0 17.5 1 42 60 1.038 22.3 62.6 0.246 0.929 0.389 0.63
17.0 125.0 1 10.0 17.5 1 42 60 1.006 21.8 62.6 0.240 0.925 0.392 0.61
18.0 125.0 1 10.0 17.5 1 42 60 0.977 21.4 62.6 0.235 0.920 0.395 0.59
19.0 125.0 1 10.0 17.5 1 42 60 0.950 21.0 62.6 0.230 0.915 0.397 0.58
20.0 125.0 1 10.0 17.5 1 42 60 0.926 20.7 62.6 0.226 0.911 0.398 0.57
21.0 125.0 1 10.0 17.5 1 42 60 0.903 20.3 62.6 0.222 0.906 0.400 0.55
22.0 125.0 1 10.0 17.5 1 42 60 0.881 20.0 62.6 0.218 0.902 0.401 0.54
23.0 125.0 1 7.0 22.5 1 42 48 0.862 16.7 62.6 0.181 0.897 0.401 0.45
24.0 125.0 1 7.0 22.5 1 42 48 0.843 16.4 62.6 0.179 0.893 0.402 0.45
25.0 125.0 1 22.0 27.5 1 35 82 0.826 37.7 62.6 Infin.0.888 0.402 Non-Liq.
26.0 125.0 1 22.0 27.5 1 35 82 0.809 37.1 62.6 Infin.0.883 0.402 Non-Liq.
27.0 125.0 1 22.0 27.5 1 35 82 0.798 36.6 62.6 Infin.0.879 0.402 Non-Liq.
28.0 125.0 1 22.0 27.5 1 35 82 0.790 36.4 62.6 Infin.0.874 0.402 Non-Liq.
29.0 125.0 1 22.0 27.5 1 35 82 0.783 36.1 62.6 Infin.0.870 0.402 Non-Liq.
30.0 125.0 1 22.0 27.5 1 35 82 0.776 35.8 62.6 Infin.0.865 0.402 Non-Liq.
31.0 125.0 1 22.0 27.5 1 35 82 0.769 35.6 62.6 Infin.0.861 0.401 Non-Liq.
32.0 125.0 1 22.0 27.5 1 35 82 0.762 35.3 62.6 Infin.0.856 0.400 Non-Liq.
33.0 125.0 1 9.0 32.5 1 39 50 0.756 18.7 62.6 0.201 0.851 0.400 0.50
34.0 125.0 1 9.0 32.5 1 39 50 0.749 18.6 62.6 0.200 0.847 0.399 0.50
35.0 125.0 1 26.0 37.5 1 38 83 0.743 40.3 62.6 Infin.0.842 0.398 Non-Liq.
36.0 125.0 1 26.0 37.5 1 38 83 0.737 40.1 62.6 Infin.0.838 0.397 Non-Liq.
37.0 125.0 1 26.0 37.5 1 38 83 0.731 39.8 62.6 Infin.0.833 0.396 Non-Liq.
38.0 125.0 1 26.0 37.5 1 38 83 0.725 39.5 62.6 Infin.0.829 0.395 Non-Liq.
39.0 125.0 1 26.0 37.5 1 38 83 0.720 39.3 62.6 Infin.0.824 0.393 Non-Liq.
40.0 125.0 1 22.0 40.0 1 40 75 0.714 34.1 62.6 Infin.0.819 0.392 Non-Liq.
41.0 125.0 1 22.0 40.0 1 40 75 0.709 33.9 62.6 Infin.0.815 0.391 Non-Liq.
42.0 125.0 1 32.0 42.5 1 89 0.703 38.8 62.6 Infin.0.810 0.389 Non-Liq.
43.0 125.0 1 32.0 42.5 1 89 0.698 38.5 62.6 Infin.0.806 0.388 Non-Liq.
44.0 125.0 1 32.0 42.5 1 89 0.693 38.3 62.6 Infin.0.801 0.387 Non-Liq.
45.0 125.0 1 32.0 42.5 1 89 0.688 38.0 62.6 Infin.0.797 0.385 Non-Liq.
46.0 125.0 1 32.0 42.5 1 89 0.683 37.7 62.6 Infin.0.792 0.384 Non-Liq.
47.0 125.0 1 62.0 47.5 1 120 0.679 72.6 62.6 Infin.0.787 0.382 Non-Liq.
48.0 125.0 1 62.0 47.5 1 120 0.674 72.1 62.6 Infin.0.783 0.380 Non-Liq.
49.0 125.0 1 62.0 47.5 1 120 0.669 71.6 62.6 Infin.0.778 0.379 Non-Liq.
50.0 125.0 1 62.0 47.5 1 120 0.665 71.1 62.6 Infin.0.774 0.377 Non-Liq.
Figure 4
Client :Lake Resort Apartments
File No. :T2719-22-02
Boring :1
NCEER (1996) METHOD
EARTHQUAKE INFORMATION:
Earthquake Magnitude:6.49
PGAM (g):0.877
2/3 PGAM (g):0.58
Calculated Mag.Wtg.Factor:0.694
Historic High Groundwater:5.0
Groundwater @ Exploration:26.5
DEPTH BLOW WET TOTAL EFFECT REL.ADJUST LIQUEFACTION Volumetric EQ.
TO COUNT DENSITY STRESS STRESS DEN.BLOWS SAFETY Strain SETTLE.
BASE N (PCF)O (TSF)O' (TSF)Dr (%)Tav/σ'o FACTOR [e15} (%)Pe (in.)
1.0 19 125 0.031 0.031 95 49 0.380 --0.00 Grading
2.0 19 125 0.094 0.094 95 49 0.380 --0.00 Grading
3.0 19 125 0.156 0.156 95 49 0.380 --0.00 Grading
4.0 19 125 0.219 0.219 95 49 0.380 --0.00 Grading
5.0 19 125 0.281 0.266 95 47 0.403 Non-Liq.0.00 Grading
6.0 19 125 0.344 0.297 95 43 0.440 Non-Liq.0.00 Grading
7.0 12 125 0.406 0.328 73 32 0.471 Non-Liq.0.00 0.00
8.0 12 125 0.469 0.360 73 30 0.496 Non-Liq.0.00 0.00
9.0 12 125 0.531 0.391 73 29 0.517 1.09 0.75 0.09
10.0 12 125 0.594 0.422 73 28 0.535 0.95 0.75 0.09
11.0 12 125 0.656 0.453 73 27 0.550 0.87 1.10 0.13
12.0 6 125 0.719 0.485 49 16 0.564 0.48 1.70 0.20
13.0 6 125 0.781 0.516 49 16 0.576 0.46 1.70 0.20
14.0 6 125 0.844 0.547 49 16 0.586 0.45 1.70 0.20
15.0 10 125 0.906 0.579 60 23 0.595 0.66 1.30 0.16
16.0 10 125 0.969 0.610 60 22 0.604 0.63 1.40 0.17
17.0 10 125 1.031 0.641 60 22 0.611 0.61 1.40 0.17
18.0 10 125 1.094 0.673 60 21 0.618 0.59 1.40 0.17
19.0 10 125 1.156 0.704 60 21 0.625 0.58 1.40 0.17
20.0 10 125 1.219 0.735 60 21 0.630 0.57 1.40 0.17
21.0 10 125 1.281 0.766 60 20 0.636 0.55 1.40 0.17
22.0 10 125 1.344 0.798 60 20 0.640 0.54 1.40 0.17
23.0 7 125 1.406 0.829 48 17 0.645 0.45 1.70 0.20
24.0 7 125 1.469 0.860 48 16 0.649 0.45 1.70 0.20
25.0 22 125 1.531 0.892 82 38 0.653 Non-Liq.0.00 0.00
26.0 22 125 1.594 0.923 82 37 0.657 Non-Liq.0.00 0.00
27.0 22 125 1.656 0.954 82 37 0.660 Non-Liq.0.00 0.00
28.0 22 125 1.719 0.986 82 36 0.663 Non-Liq.0.00 0.00
29.0 22 125 1.781 1.017 82 36 0.666 Non-Liq.0.00 0.00
30.0 22 125 1.844 1.048 82 36 0.669 Non-Liq.0.00 0.00
31.0 22 125 1.906 1.079 82 36 0.671 Non-Liq.0.00 0.00
32.0 22 125 1.969 1.111 82 35 0.674 Non-Liq.0.00 0.00
33.0 9 125 2.031 1.142 50 19 0.676 0.50 1.60 0.19
34.0 9 125 2.094 1.173 50 19 0.678 0.50 1.60 0.19
35.0 26 125 2.156 1.205 83 40 0.681 Non-Liq.0.00 0.00
36.0 26 125 2.219 1.236 83 40 0.683 Non-Liq.0.00 0.00
37.0 26 125 2.281 1.267 83 40 0.684 Non-Liq.0.00 0.00
38.0 26 125 2.344 1.299 83 40 0.686 Non-Liq.0.00 0.00
39.0 26 125 2.406 1.330 83 39 0.688 Non-Liq.0.00 0.00
40.0 22 125 2.469 1.361 75 34 0.690 Non-Liq.0.00 0.00
41.0 22 125 2.531 1.392 75 34 0.691 Non-Liq.0.00 0.00
42.0 32 125 2.594 1.424 89 39 0.693 Non-Liq.0.00 0.00
43.0 32 125 2.656 1.455 89 39 0.694 Non-Liq.0.00 0.00
44.0 32 125 2.719 1.486 89 38 0.695 Non-Liq.0.00 0.00
45.0 32 125 2.781 1.518 89 38 0.697 Non-Liq.0.00 0.00
46.0 32 125 2.844 1.549 89 38 0.698 Non-Liq.0.00 0.00
47.0 62 125 2.906 1.580 120 73 0.699 Non-Liq.0.00 0.00
48.0 62 125 2.969 1.612 120 72 0.700 Non-Liq.0.00 0.00
49.0 62 125 3.031 1.643 120 72 0.702 Non-Liq.0.00 0.00
50.0 62 125 3.094 1.674 120 71 0.703 Non-Liq.0.00 0.00
TOTAL SETTLEMENT = 3.0 INCHES
(SATURATED SAND AT INITIAL LIQUEFACTION CONDITION)
DESIGN EARTHQUAKE
LIQUEFACTION SETTLEMENT ANALYSIS
Figure 5
Client :Lake Resort Apartments
File No. :T2719-22-02
Boring :1
EMPIRICAL ESTIMATION OF LIQUEFACTION POTENTIAL
MAXIMUM CONSIDERED EARTHQUAKE
NCEER (1996) METHOD By Thomas F. Blake (1994-1996)
EARTHQUAKE INFORMATION:ENERGY & ROD CORRECTIONS:
Earthquake Magnitude:7.71 Energy Correction (CE) for N60:1.25
Peak Horiz. Acceleration PGAM (g):0.877 Rod Len.Corr.(CR)(0-no or 1-yes):1.0
Calculated Mag.Wtg.Factor:1.078 Bore Dia. Corr. (CB):1.15
Historic High Groundwater:5.0 Sampler Corr. (CS):1.20
Groundwater Depth During Exploration:26.5 Use Ksigma (0 or 1):1.0
LIQUEFACTION CALCULATIONS:
Unit Wt. Water (pcf):62.4
Depth to Total Unit Water FIELD Depth of Liq.Sus.-200 Est. Dr CN Corrected Eff. Unit Resist.rd Induced Liquefac.
Base (ft)Wt. (pcf)(0 or 1)SPT (N)SPT (ft)(0 or 1)(%)(%)Factor (N1)60 Wt. (psf)CRR Factor CSR Safe.Fact.
1.0 125.0 0 19.0 5.0 1 95 2.000 49.2 125.0 Infin.0.998 0.613 --
2.0 125.0 0 19.0 5.0 1 95 2.000 49.2 125.0 Infin.0.993 0.611 --
3.0 125.0 0 19.0 5.0 1 95 2.000 49.2 125.0 Infin.0.989 0.608 --
4.0 125.0 0 19.0 5.0 1 95 2.000 49.2 125.0 Infin.0.984 0.605 --
5.0 125.0 1 19.0 5.0 1 95 1.927 47.4 62.6 Infin.0.979 0.638 Non-Liq.
6.0 125.0 1 19.0 5.0 1 95 1.743 42.8 62.6 Infin.0.975 0.694 Non-Liq.
7.0 125.0 1 12.0 7.5 1 36 73 1.603 31.9 62.6 Infin.0.970 0.738 Non-Liq.
8.0 125.0 1 12.0 7.5 1 36 73 1.492 30.2 62.6 Infin.0.966 0.774 Non-Liq.
9.0 125.0 1 12.0 7.5 1 36 73 1.402 28.8 62.6 0.375 0.961 0.803 0.47
10.0 125.0 1 12.0 7.5 1 36 73 1.326 27.6 62.6 0.338 0.957 0.827 0.41
11.0 125.0 1 12.0 7.5 1 36 73 1.261 26.6 62.6 0.315 0.952 0.847 0.37
12.0 125.0 1 6.0 12.5 1 36 49 1.205 16.4 62.6 0.178 0.947 0.864 0.21
13.0 125.0 1 6.0 12.5 1 36 49 1.156 16.0 62.6 0.174 0.943 0.878 0.20
14.0 125.0 1 6.0 12.5 1 36 49 1.112 15.6 62.6 0.170 0.938 0.889 0.19
15.0 125.0 1 10.0 17.5 1 42 60 1.073 22.8 62.6 0.253 0.934 0.899 0.28
16.0 125.0 1 10.0 17.5 1 42 60 1.038 22.3 62.6 0.246 0.929 0.907 0.27
17.0 125.0 1 10.0 17.5 1 42 60 1.006 21.8 62.6 0.240 0.925 0.914 0.26
18.0 125.0 1 10.0 17.5 1 42 60 0.977 21.4 62.6 0.235 0.920 0.920 0.26
19.0 125.0 1 10.0 17.5 1 42 60 0.950 21.0 62.6 0.230 0.915 0.925 0.25
20.0 125.0 1 10.0 17.5 1 42 60 0.926 20.7 62.6 0.226 0.911 0.928 0.24
21.0 125.0 1 10.0 17.5 1 42 60 0.903 20.3 62.6 0.222 0.906 0.931 0.24
22.0 125.0 1 10.0 17.5 1 42 60 0.881 20.0 62.6 0.218 0.902 0.934 0.23
23.0 125.0 1 7.0 22.5 1 42 48 0.862 16.7 62.6 0.181 0.897 0.936 0.19
24.0 125.0 1 7.0 22.5 1 42 48 0.843 16.4 62.6 0.179 0.893 0.937 0.19
25.0 125.0 1 22.0 27.5 1 35 82 0.826 37.7 62.6 Infin.0.888 0.938 Non-Liq.
26.0 125.0 1 22.0 27.5 1 35 82 0.809 37.1 62.6 Infin.0.883 0.938 Non-Liq.
27.0 125.0 1 22.0 27.5 1 35 82 0.798 36.6 62.6 Infin.0.879 0.938 Non-Liq.
28.0 125.0 1 22.0 27.5 1 35 82 0.790 36.4 62.6 Infin.0.874 0.937 Non-Liq.
29.0 125.0 1 22.0 27.5 1 35 82 0.783 36.1 62.6 Infin.0.870 0.937 Non-Liq.
30.0 125.0 1 22.0 27.5 1 35 82 0.776 35.8 62.6 Infin.0.865 0.936 Non-Liq.
31.0 125.0 1 22.0 27.5 1 35 82 0.769 35.6 62.6 Infin.0.861 0.934 Non-Liq.
32.0 125.0 1 22.0 27.5 1 35 82 0.762 35.3 62.6 Infin.0.856 0.933 Non-Liq.
33.0 125.0 1 9.0 32.5 1 39 50 0.756 18.7 62.6 0.201 0.851 0.931 0.22
34.0 125.0 1 9.0 32.5 1 39 50 0.749 18.6 62.6 0.200 0.847 0.929 0.22
35.0 125.0 1 26.0 37.5 1 38 83 0.743 40.3 62.6 Infin.0.842 0.927 Non-Liq.
36.0 125.0 1 26.0 37.5 1 38 83 0.737 40.1 62.6 Infin.0.838 0.925 Non-Liq.
37.0 125.0 1 26.0 37.5 1 38 83 0.731 39.8 62.6 Infin.0.833 0.922 Non-Liq.
38.0 125.0 1 26.0 37.5 1 38 83 0.725 39.5 62.6 Infin.0.829 0.919 Non-Liq.
39.0 125.0 1 26.0 37.5 1 38 83 0.720 39.3 62.6 Infin.0.824 0.917 Non-Liq.
40.0 125.0 1 22.0 40.0 1 40 75 0.714 34.1 62.6 Infin.0.819 0.914 Non-Liq.
41.0 125.0 1 22.0 40.0 1 40 75 0.709 33.9 62.6 Infin.0.815 0.911 Non-Liq.
42.0 125.0 1 32.0 42.5 1 89 0.703 38.8 62.6 Infin.0.810 0.908 Non-Liq.
43.0 125.0 1 32.0 42.5 1 89 0.698 38.5 62.6 Infin.0.806 0.904 Non-Liq.
44.0 125.0 1 32.0 42.5 1 89 0.693 38.3 62.6 Infin.0.801 0.901 Non-Liq.
45.0 125.0 1 32.0 42.5 1 89 0.688 38.0 62.6 Infin.0.797 0.897 Non-Liq.
46.0 125.0 1 32.0 42.5 1 89 0.683 37.7 62.6 Infin.0.792 0.894 Non-Liq.
47.0 125.0 1 62.0 47.5 1 120 0.679 72.6 62.6 Infin.0.787 0.890 Non-Liq.
48.0 125.0 1 62.0 47.5 1 120 0.674 72.1 62.6 Infin.0.783 0.887 Non-Liq.
49.0 125.0 1 62.0 47.5 1 120 0.669 71.6 62.6 Infin.0.778 0.883 Non-Liq.
50.0 125.0 1 62.0 47.5 1 120 0.665 71.1 62.6 Infin.0.774 0.879 Non-Liq.
Figure 6
Client :Lake Resort Apartments
File No. :T2719-22-02
Boring :1
NCEER (1996) METHOD
EARTHQUAKE INFORMATION:
Earthquake Magnitude:7.71
PGAM (g):0.877
Calculated Mag.Wtg.Factor:1.078
Historic High Groundwater:5.0
Groundwater @ Exploration:26.5
DEPTH BLOW WET TOTAL EFFECT REL.ADJUST LIQUEFACTION Volumetric EQ.
TO COUNT DENSITY STRESS STRESS DEN.BLOWS SAFETY Strain SETTLE.
BASE N (PCF)O (TSF)O' (TSF)Dr (%)Tav/σ'o FACTOR [e15} (%)Pe (in.)
1.0 19 125 0.031 0.031 95 49 0.570 --0.00 Grading
2.0 19 125 0.094 0.094 95 49 0.570 --0.00 Grading
3.0 19 125 0.156 0.156 95 49 0.570 --0.00 Grading
4.0 19 125 0.219 0.219 95 49 0.570 --0.00 Grading
5.0 19 125 0.281 0.266 95 47 0.604 Non-Liq.0.00 Grading
6.0 19 125 0.344 0.297 95 43 0.660 Non-Liq.0.00 Grading
7.0 12 125 0.406 0.328 73 32 0.706 Non-Liq.0.00 0.00
8.0 12 125 0.469 0.360 73 30 0.743 Non-Liq.0.00 0.00
9.0 12 125 0.531 0.391 73 29 0.775 0.47 0.75 0.09
10.0 12 125 0.594 0.422 73 28 0.802 0.41 0.75 0.09
11.0 12 125 0.656 0.453 73 27 0.825 0.37 1.10 0.13
12.0 6 125 0.719 0.485 49 16 0.845 0.21 1.70 0.20
13.0 6 125 0.781 0.516 49 16 0.863 0.20 1.70 0.20
14.0 6 125 0.844 0.547 49 16 0.879 0.19 1.70 0.20
15.0 10 125 0.906 0.579 60 23 0.893 0.28 1.30 0.16
16.0 10 125 0.969 0.610 60 22 0.905 0.27 1.40 0.17
17.0 10 125 1.031 0.641 60 22 0.917 0.26 1.40 0.17
18.0 10 125 1.094 0.673 60 21 0.927 0.26 1.40 0.17
19.0 10 125 1.156 0.704 60 21 0.936 0.25 1.40 0.17
20.0 10 125 1.219 0.735 60 21 0.945 0.24 1.40 0.17
21.0 10 125 1.281 0.766 60 20 0.953 0.24 1.40 0.17
22.0 10 125 1.344 0.798 60 20 0.960 0.23 1.40 0.17
23.0 7 125 1.406 0.829 48 17 0.967 0.19 1.70 0.20
24.0 7 125 1.469 0.860 48 16 0.973 0.19 1.70 0.20
25.0 22 125 1.531 0.892 82 38 0.979 Non-Liq.0.00 0.00
26.0 22 125 1.594 0.923 82 37 0.984 Non-Liq.0.00 0.00
27.0 22 125 1.656 0.954 82 37 0.989 Non-Liq.0.00 0.00
28.0 22 125 1.719 0.986 82 36 0.994 Non-Liq.0.00 0.00
29.0 22 125 1.781 1.017 82 36 0.999 Non-Liq.0.00 0.00
30.0 22 125 1.844 1.048 82 36 1.003 Non-Liq.0.00 0.00
31.0 22 125 1.906 1.079 82 36 1.007 Non-Liq.0.00 0.00
32.0 22 125 1.969 1.111 82 35 1.010 Non-Liq.0.00 0.00
33.0 9 125 2.031 1.142 50 19 1.014 0.22 1.60 0.19
34.0 9 125 2.094 1.173 50 19 1.017 0.22 1.60 0.19
35.0 26 125 2.156 1.205 83 40 1.020 Non-Liq.0.00 0.00
36.0 26 125 2.219 1.236 83 40 1.023 Non-Liq.0.00 0.00
37.0 26 125 2.281 1.267 83 40 1.026 Non-Liq.0.00 0.00
38.0 26 125 2.344 1.299 83 40 1.029 Non-Liq.0.00 0.00
39.0 26 125 2.406 1.330 83 39 1.031 Non-Liq.0.00 0.00
40.0 22 125 2.469 1.361 75 34 1.034 Non-Liq.0.00 0.00
41.0 22 125 2.531 1.392 75 34 1.036 Non-Liq.0.00 0.00
42.0 32 125 2.594 1.424 89 39 1.039 Non-Liq.0.00 0.00
43.0 32 125 2.656 1.455 89 39 1.041 Non-Liq.0.00 0.00
44.0 32 125 2.719 1.486 89 38 1.043 Non-Liq.0.00 0.00
45.0 32 125 2.781 1.518 89 38 1.045 Non-Liq.0.00 0.00
46.0 32 125 2.844 1.549 89 38 1.047 Non-Liq.0.00 0.00
47.0 62 125 2.906 1.580 120 73 1.048 Non-Liq.0.00 0.00
48.0 62 125 2.969 1.612 120 72 1.050 Non-Liq.0.00 0.00
49.0 62 125 3.031 1.643 120 72 1.052 Non-Liq.0.00 0.00
50.0 62 125 3.094 1.674 120 71 1.053 Non-Liq.0.00 0.00
TOTAL SETTLEMENT = 3.0 INCHES
(SATURATED SAND AT INITIAL LIQUEFACTION CONDITION)
LIQUEFACTION SETTLEMENT ANALYSIS
MAXIMUM CONSIDERED EARTHQUAKE
APPENDIX A
Geocon Project No. T2719-22-02 -A-1- February 22, 2022
APPENDIX A
FIELD INVESTIGATION
We drilled four percolation borings to depths of four feet on the site on February 2, 2022 and percolation
testing was performed on February 3, 2022. Prior field investigations were performed on May 12 and
August 30, 2016. The borings were excavated with an 8-inch hollow-stem auger drill to a maximum
depth of 51.8 feet. Bulk samples of disturbed soils and ring samples of in -situ soils were transported
to our laboratory for testing. Each boring was backfilled with the cuttings generated during
excavation.
We obtained soil samples from the borings during our subsurface exploration using a California
sampler. The sampler is composed of steel and is driven to obtain relatively undisturbed samples.
The sampler was driven up to 18 inches. The sampler is connecte d to A rods and driven into the
bottom of the boring using a 140-pound hammer. The California sampler has an inside diameter of
2.5 inches and an outside diameter of 3 inches. Rings are placed inside the sampler that are 2.4 inches
in diameter and 1 inch i n height. We obtained ring samples at appropriate intervals, placed them in
moisture-tight containers, and transported them to the laboratory for testing. We also utilized a
standard penetration sampler (SPT) alternately with the California sampler within one deep boring
on the site to provide standard penetration resistance values necessary for liquefaction analysis.
SPT samples were placed in plastic bags and transported to the laboratory. Disturbed bulk samples
were also collected and transported back to the laboratory for testing.
Blow counts were recorded for every 6 inches the sampler was driven. The penetration resistances
shown on the boring logs are shown in terms of blows per foot. These values are not to be taken as
N-values as adjustments have not been applied.
The soil conditions encountered in the excavations were visually examined, classified and logged in
general accordance with the Unified Soil Classification System (USCS). Logs of the bore holes are
presented on Figures A-1 through A-4 and previous geotechnical borings within the proposed
development area of the site (Borings 1 through 6, and 10). The logs depict the soil and geologic
conditions encountered and the depth at which samples were obtained. The approximate locations of
the boreholes are indicated the Geotechnical Map, Figure 2. We estimated elevations shown on the
boring logs either from a topographic map or by using a benchmark.
P-1@5'19
SM
SM
ALLUVIAL FAN DEPOSITS (Qyf)
Silty SAND, loose, moist, brown
Silty SAND, loose, dry, brown; some pea gravel
Total Depth = 6' 6" feet
Perc set at 5'
Presaturated with 5 gal H2O
Perc performed on 02/03/2022
Pipe removed and backfilled with native soil CONTENT (%)... SAMPLING UNSUCCESSFUL
... DISTURBED OR BAG SAMPLE
SOIL
CLASS
(USCS)GROUNDWATERFigure A-1,
Log of Boring P-1, Page 1 of 1
GEOCON(P.C.F.)DATE COMPLETED
SAMPLE SYMBOLS
SAMPLE
NO.(BLOWS/FT.) T2719-22-02 BORING LOGS.GPJ
MATERIAL DESCRIPTIONLITHOLOGY
... STANDARD PENETRATION TEST
1276
HOLLOW STEM AUGER
... DRIVE SAMPLE (UNDISTURBED)PENETRATIONMOISTUREBY:L. BATTIATO
2/2/2022
... WATER TABLE OR SEEPAGE
DEPTH
IN
FEET
0
2
4
6 RESISTANCEDRY DENSITYELEV. (MSL.)
EQUIPMENT
BORING P-1
... CHUNK SAMPLE
NOTE:
PROJECT NO.
THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED. IT
IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
T2719-22-02
P-2@5'19
SM
SM
UNDOCUMENTED FILL (afu)
Silty SAND, loose, moist, very dark brown
-Becomes medium yellow brown
Silty SAND, dry, yellow brown; trace pea gravel
Total Depth = 6' 6" feet
Perc set at 5'
Presaturated with 5 gal H2O
Perc performed on 02/03/2022
Pipe removed and backfilled with native soil CONTENT (%)... SAMPLING UNSUCCESSFUL
... DISTURBED OR BAG SAMPLE
SOIL
CLASS
(USCS)GROUNDWATERFigure A-2,
Log of Boring P-2, Page 1 of 1
GEOCON(P.C.F.)DATE COMPLETED
SAMPLE SYMBOLS
SAMPLE
NO.(BLOWS/FT.) T2719-22-02 BORING LOGS.GPJ
MATERIAL DESCRIPTIONLITHOLOGY
... STANDARD PENETRATION TEST
1271
HOLLOW STEM AUGER
... DRIVE SAMPLE (UNDISTURBED)PENETRATIONMOISTUREBY:L. BATTIATO
2/2/2022
... WATER TABLE OR SEEPAGE
DEPTH
IN
FEET
0
2
4
6 RESISTANCEDRY DENSITYELEV. (MSL.)
EQUIPMENT
BORING P-2
... CHUNK SAMPLE
NOTE:
PROJECT NO.
THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED. IT
IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
T2719-22-02
P-3@5'21
SM
SM
UNDOCUMENTED FILL (afu)
Silty SAND, loose, moist, very dark brown; organic odor
-Becomes medium brown at 4'
Silty SAND, dry, yellow brown; some pea gravel
Total Depth = 6' 6" feet
Perc set at 5'
Presaturated with 5 gal H2O
Perc performed on 02/03/2022
Pipe removed and backfilled with native soil CONTENT (%)... SAMPLING UNSUCCESSFUL
... DISTURBED OR BAG SAMPLE
SOIL
CLASS
(USCS)GROUNDWATERFigure A-3,
Log of Boring P-3, Page 1 of 1
GEOCON(P.C.F.)DATE COMPLETED
SAMPLE SYMBOLS
SAMPLE
NO.(BLOWS/FT.) T2719-22-02 BORING LOGS.GPJ
MATERIAL DESCRIPTIONLITHOLOGY
... STANDARD PENETRATION TEST
1266
HOLLOW STEM AUGER
... DRIVE SAMPLE (UNDISTURBED)PENETRATIONMOISTUREBY:L. BATTIATO
2/2/2022
... WATER TABLE OR SEEPAGE
DEPTH
IN
FEET
0
2
4
6 RESISTANCEDRY DENSITYELEV. (MSL.)
EQUIPMENT
BORING P-3
... CHUNK SAMPLE
NOTE:
PROJECT NO.
THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED. IT
IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
T2719-22-02
P-4@5'11
ML
ML
UNDOCUMENTED FILL (afu)
SILT, loose, moist, dark brown; medium sand
SILT, firm, damp, olive brown; porous, carbonate stringers
Total Depth = 6' 6" feet
Perc set at 5'
Presaturated with 5 gal H2O
Perc performed on 02/03/2022
Pipe removed and backfilled with native soil CONTENT (%)... SAMPLING UNSUCCESSFUL
... DISTURBED OR BAG SAMPLE
SOIL
CLASS
(USCS)GROUNDWATERFigure A-4,
Log of Boring P-4, Page 1 of 1
GEOCON(P.C.F.)DATE COMPLETED
SAMPLE SYMBOLS
SAMPLE
NO.(BLOWS/FT.) T2719-22-02 BORING LOGS.GPJ
MATERIAL DESCRIPTIONLITHOLOGY
... STANDARD PENETRATION TEST
1271
HOLLOW STEM AUGER
... DRIVE SAMPLE (UNDISTURBED)PENETRATIONMOISTUREBY:L. BATTIATO
2/2/2022
... WATER TABLE OR SEEPAGE
DEPTH
IN
FEET
0
2
4
6 RESISTANCEDRY DENSITYELEV. (MSL.)
EQUIPMENT
BORING P-4
... CHUNK SAMPLE
NOTE:
PROJECT NO.
THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED. IT
IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
T2719-22-02
B-1@0'-5'
B-1@2.5'
B-1@5.0'
B-1@7.5'
B-1@10.0'
B-1@12.5'
B-1@15.0'
B-1@17.5'
B-1@20.0'
B-1@22.5'
B-1@25.0'
B-1@27.5'
15
35
22
21
6
26
10
18
7
38
22
101.1
122.4
109.6
121.3
SM
SM
7.0
9.3
20.7
14.4
UNDOCUMENTED FILL (afu)
Silty SAND, loose, slightly moist, blackish dark brown; fine to medium
sand; some coarse sand; micaceous; trace porosity; root hairs; some weeds
-Becomes medium dense; trace light brown modling
ALLUVIAL FAN DEPOSITS (Qyf)
Silty SAND, medium dense, moist, strong brown; fine to coarse sand;
micaceous; trace fine gravel; non-porous
-Becomes loose
-Becomes medium dense, brown; trace clay
-Becomes loose, wet; increase in clay
-Becomes grayish brown
-Becomes medium dense, saturated, brown; fine to coarse sand; some
gravel
-Becomes medium dense CONTENT (%)... SAMPLING UNSUCCESSFUL
... DISTURBED OR BAG SAMPLE
SOIL
CLASS
(USCS)GROUNDWATERFigure A-1,
Log of Boring B-1, Page 1 of 2
GEOCON(P.C.F.)DATE COMPLETED
SAMPLE SYMBOLS
SAMPLE
NO.(BLOWS/FT.) T2719-22-01 BORING LOGS.GPJ
MATERIAL DESCRIPTIONLITHOLOGY
... STANDARD PENETRATION TEST
1262
HOLLOW STEM AUGER
... DRIVE SAMPLE (UNDISTURBED)PENETRATIONMOISTUREBY:P. Theriault
05/12/2016
... WATER TABLE OR SEEPAGE
DEPTH
IN
FEET
0
2
4
6
8
10
12
14
16
18
20
22
24
26
28 RESISTANCEDRY DENSITYELEV. (MSL.)
EQUIPMENT
BORING B-1
... CHUNK SAMPLE
NOTE:
PROJECT NO.
THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED. IT
IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
T2719-22-01
B-1@30.0'
B-1@32.5'
B-1@35'
B-1@37.5'
B-1@40'
B-1@42.5'
B-1@45'
B-1@47.5'
B-1@50'
20
9
62
26
39
32
50-5"
62
50-3"
SM
SM
ALLUVIAL FAN DEPOSITS (Qyf)
Silty SAND, medium dense, moist, brown; fine to coarse sand; increase in
clay
PAUBA FORMATION FANGLOMERATE (Qpfs)
Silty SAND, dense, moist, mottled orange and grayish brown; fine to
medium sand; some coarse sand; micaceous; moderately cemented
-Becomes dense, brown; trace clay; micaceous
-Becomes reddish brown; no clay
-Becomes wet
-Becomes strong brown
Total depth 51 feet, 9 inches
Groundwater encountered at 36 feet, 11 inches. Stabilized at 26 feet, 6
inches
No caving
Penetration resistance for 140 lb. hammer falling 30" by auto-hammer
Backfilled with cuttings on 5/12/2016 CONTENT (%)... SAMPLING UNSUCCESSFUL
... DISTURBED OR BAG SAMPLE
SOIL
CLASS
(USCS)GROUNDWATERFigure A-1,
Log of Boring B-1, Page 2 of 2
GEOCON(P.C.F.)DATE COMPLETED
SAMPLE SYMBOLS
SAMPLE
NO.(BLOWS/FT.) T2719-22-01 BORING LOGS.GPJ
MATERIAL DESCRIPTIONLITHOLOGY
... STANDARD PENETRATION TEST
1262
HOLLOW STEM AUGER
... DRIVE SAMPLE (UNDISTURBED)PENETRATIONMOISTUREBY:P. Theriault
05/12/2016
... WATER TABLE OR SEEPAGE
DEPTH
IN
FEET
30
32
34
36
38
40
42
44
46
48
50 RESISTANCEDRY DENSITYELEV. (MSL.)
EQUIPMENT
BORING B-1
... CHUNK SAMPLE
NOTE:
PROJECT NO.
THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED. IT
IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
T2719-22-01
B-2@2.5'
B-2@5'
B-2@7.5'
B-2@10'
B-2@15'
13
41
18
22
30
111.1
SM
SM
6.1
UNDOCUMENTED FILL (afu)
Silty SAND, medium dense, slightly moist, dark gray; fine to coarse sand;
micaceous; root hairs
-Becomes moist
ALLUVIAL FAN DEPOSITS (Qyf)
Silty SAND, medium dense, moist, dark gray; fine to coarse sand;
micaceous
-Poorly developed carbonate stringers
-Becomes brown; decrease in coarse sand
-Becomes reddish brown; no carbonates
-Becomes brownish gray; trace gravel
Total depth 16.5 feet
No groundwater encountered
No caving
Penetration resistance for 140 lb. hammer falling 30" by auto-hammer
Backfilled with cuttings on 5/12/2016 CONTENT (%)... SAMPLING UNSUCCESSFUL
... DISTURBED OR BAG SAMPLE
SOIL
CLASS
(USCS)GROUNDWATERFigure A-2,
Log of Boring B-2, Page 1 of 1
GEOCON(P.C.F.)DATE COMPLETED
SAMPLE SYMBOLS
SAMPLE
NO.(BLOWS/FT.) T2719-22-01 BORING LOGS.GPJ
MATERIAL DESCRIPTIONLITHOLOGY
... STANDARD PENETRATION TEST
1263
HOLLOW STEM AUGER
... DRIVE SAMPLE (UNDISTURBED)PENETRATIONMOISTUREBY:P. Theriault
05/12/2016
... WATER TABLE OR SEEPAGE
DEPTH
IN
FEET
0
2
4
6
8
10
12
14
16 RESISTANCEDRY DENSITYELEV. (MSL.)
EQUIPMENT
BORING B-2
... CHUNK SAMPLE
NOTE:
PROJECT NO.
THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED. IT
IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
T2719-22-01
B-3@0-5'
B-3@2.5'
B-3@5'
B-3@7.5'
B-3@10'
B-3@12.5'
B-3@15'
B-3@20'
B-3@25'
20
26
43
28
36
30
30
90-11"
118.2
116.3
123.4
112.1
SM
SM
4.7
2.5
5.1
5.3
ALLUVIAL FAN DEPOSITS (Qyf)
Silty SAND, medium dense, slightly moist, blackish dark brown; fine to
coarse sand; micaceous; some weeds
-Becomes brown; root hairs; trace gravel
-Becomes moist; trace carbonate stringers (poorly developed)
-Becomes reddish brown; carbonate stringers (poorly developed)
-Gravel layer; no carbonates
-Becomes wet; some clay
PAUBA FORMATION FANGLOMERATE (Qpfs)
Silty SAND, very dense, moist, mottled reddish brown and gray; fine to
coarse sand; micaceous; trace fine gravel
Total depth 26.5 feet
No groundwater encountered
No caving
Penetration resistance for 140 lb. hammer falling 30" by auto-hammer
Backfilled with cuttings on 5/12/2016 CONTENT (%)... SAMPLING UNSUCCESSFUL
... DISTURBED OR BAG SAMPLE
SOIL
CLASS
(USCS)GROUNDWATERFigure A-3,
Log of Boring B-3, Page 1 of 1
GEOCON(P.C.F.)DATE COMPLETED
SAMPLE SYMBOLS
SAMPLE
NO.(BLOWS/FT.) T2719-22-01 BORING LOGS.GPJ
MATERIAL DESCRIPTIONLITHOLOGY
... STANDARD PENETRATION TEST
1270
HOLLOW STEM AUGER
... DRIVE SAMPLE (UNDISTURBED)PENETRATIONMOISTUREBY:P. Theriault
05/12/2016
... WATER TABLE OR SEEPAGE
DEPTH
IN
FEET
0
2
4
6
8
10
12
14
16
18
20
22
24
26 RESISTANCEDRY DENSITYELEV. (MSL.)
EQUIPMENT
BORING B-3
... CHUNK SAMPLE
NOTE:
PROJECT NO.
THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED. IT
IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
T2719-22-01
B-4@2.5'
B-4@5'
B-4@7.5'
B-4@10'
B-4@12.5'
B-4@15'
B-4@20'
B-4@25'
26
41
31
22
20
26
40
35
SM
SM
ALLUVIAL FAN DEPOSITS (Qyf)
Silty SAND, medium dense, slightly moist, blackish dark brown; fine to
coarse sand; micaceous; some weeds
-Becomes brown; weak carbonate stringers; decrease in coarse sand
-Becomes moist, reddish brown; carbonate stringers
-Becomes strong brown; no carbonates
-Increase in coarse sand; trace fine gravel (in shoe)
PAUBA FORMATION FANGLOMERATE (Qpfs)
Silty SAND, medium dense, moist, mottled reddish brown and brown; fine
to coarse sand; some gravel; micaceous
-No recovery
Total depth 26.5 feet
No groundwater encountered
No caving
Penetration resistance for 140 lb. hammer falling 30" by auto-hammer
Backfilled with cuttings on 5/12/2016 CONTENT (%)... SAMPLING UNSUCCESSFUL
... DISTURBED OR BAG SAMPLE
SOIL
CLASS
(USCS)GROUNDWATERFigure A-4,
Log of Boring B-4, Page 1 of 1
GEOCON(P.C.F.)DATE COMPLETED
SAMPLE SYMBOLS
SAMPLE
NO.(BLOWS/FT.) T2719-22-01 BORING LOGS.GPJ
MATERIAL DESCRIPTIONLITHOLOGY
... STANDARD PENETRATION TEST
1268
HOLLOW STEM AUGER
... DRIVE SAMPLE (UNDISTURBED)PENETRATIONMOISTUREBY:P. Theriault
05/12/2016
... WATER TABLE OR SEEPAGE
DEPTH
IN
FEET
0
2
4
6
8
10
12
14
16
18
20
22
24
26 RESISTANCEDRY DENSITYELEV. (MSL.)
EQUIPMENT
BORING B-4
... CHUNK SAMPLE
NOTE:
PROJECT NO.
THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED. IT
IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
T2719-22-01
B-5@2.5'
B-5@5'
B-5@7.5'
B-5@10'
B-5@12.5'
B-5@15'
18
8
24
11
15
22
104.1
94.1
SM
ML
SM
4.3
23.8
UNDOCUMENTED FILL (afu)
Silty SAND, medium dense, slightly moist, brown; fine to medium sand;
chunks of AC
LACUSTRINE DEPOSITS (Ql)
Sandy SILT, firm, moist, olive; fine sand; micaceous
-Trace weakly cemented carbonate
ALLUVIAL FAN DEPOSITS (Qyf)
Silty SAND, loose, moist, brown with light brown mottling; fine to
medium sand; some coarse sand; micaceous
-Trace poorly developed carbonate
-Becomes olive; some clay
Total depth 16.5 feet
No groundwater encountered
No caving
Penetration resistance for 140 lb. hammer falling 30" by auto-hammer
Backfilled with cuttings on 5/12/2016 CONTENT (%)... SAMPLING UNSUCCESSFUL
... DISTURBED OR BAG SAMPLE
SOIL
CLASS
(USCS)GROUNDWATERFigure A-5,
Log of Boring B-5, Page 1 of 1
GEOCON(P.C.F.)DATE COMPLETED
SAMPLE SYMBOLS
SAMPLE
NO.(BLOWS/FT.) T2719-22-01 BORING LOGS.GPJ
MATERIAL DESCRIPTIONLITHOLOGY
... STANDARD PENETRATION TEST
1261
HOLLOW STEM AUGER
... DRIVE SAMPLE (UNDISTURBED)PENETRATIONMOISTUREBY:P. Theriault
05/12/2016
... WATER TABLE OR SEEPAGE
DEPTH
IN
FEET
0
2
4
6
8
10
12
14
16 RESISTANCEDRY DENSITYELEV. (MSL.)
EQUIPMENT
BORING B-5
... CHUNK SAMPLE
NOTE:
PROJECT NO.
THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED. IT
IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
T2719-22-01
B-6@0-5'
B-6@2.5'
B-6@5'
B-6@7.5'
B-6@10'
B-6@12.5'
B-6@15'
B-6@20'
B-6@25'
16
13
14
17
17
15
15
23
96.8
97.6
112.0
SM
ML
SM
SC
6.6
15.8
18.2
UNDOCUMENTED FILL (afu)
Silty SAND, medium dense, moist, gray; fine sand; micaceous; some
orange staining; debris (AC chunks and rocks)
-No debris
LACUSTRINE DEPOSITS (Ql)
Sandy SILT, stiff, moist, grayish brown; fine sand; micaceous
-Becomes brown; some clay
ALLUVIAL FAN DEPOSITS (Qyf)
Silty SAND, medium dense, moist, reddish brown; fine sand
-Becomes fine to coarse sand
Clayey SAND, stiff, moist, grayish brown; fine to coarse sand; trace fine
gravel; micaceous
Total depth 26.5 feet
No groundwater encountered
No caving
Penetration resistance for 140 lb. hammer falling 30" by auto-hammer
Backfilled with cuttings on 5/12/2016 CONTENT (%)... SAMPLING UNSUCCESSFUL
... DISTURBED OR BAG SAMPLE
SOIL
CLASS
(USCS)GROUNDWATERFigure A-6,
Log of Boring B-6, Page 1 of 1
GEOCON(P.C.F.)DATE COMPLETED
SAMPLE SYMBOLS
SAMPLE
NO.(BLOWS/FT.) T2719-22-01 BORING LOGS.GPJ
MATERIAL DESCRIPTIONLITHOLOGY
... STANDARD PENETRATION TEST
1262
HOLLOW STEM AUGER
... DRIVE SAMPLE (UNDISTURBED)PENETRATIONMOISTUREBY:P. Theriault
05/12/2016
... WATER TABLE OR SEEPAGE
DEPTH
IN
FEET
0
2
4
6
8
10
12
14
16
18
20
22
24
26 RESISTANCEDRY DENSITYELEV. (MSL.)
EQUIPMENT
BORING B-6
... CHUNK SAMPLE
NOTE:
PROJECT NO.
THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED. IT
IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
T2719-22-01
B-10@0-5'
B-10@2.5'
B-10@5'
B-10@7.5'
B-10@10'
21
47
22
23
95.2
85.9
109.3
113.1
SM
ML
SM
13.8
22.3
11.5
10.1
UNDOCUMENTED FILL (afu)
Silty SAND, medium dense, dry, brown; fine to coarse sand; weeds at
surface
SILT, stiff, slightly moist, olive brown; trace fine sand; trace mica
Silty SAND, medium dense, slightly moist, olive brown; fine to medium
sand, trace coarse sand
-Becomes brown; fine to coarse sand; trace mica
-Increase in medium sand
Total depth 11 feet, 6 inches
No groundwater encountered
No caving
Penetration resistance for 140 lb. hammer falling 30" by auto-hammer
Backfilled with cuttings on 8/30/2016 CONTENT (%)... SAMPLING UNSUCCESSFUL
... DISTURBED OR BAG SAMPLE
SOIL
CLASS
(USCS)GROUNDWATERFigure A-10,
Log of Boring B-10, Page 1 of 1
GEOCON(P.C.F.)DATE COMPLETED
SAMPLE SYMBOLS
SAMPLE
NO.(BLOWS/FT.) T2719-22-01 BORING LOGS.GPJ
MATERIAL DESCRIPTIONLITHOLOGY
... STANDARD PENETRATION TEST
1268
HOLLOW STEM AUGER
... DRIVE SAMPLE (UNDISTURBED)PENETRATIONMOISTUREBY:A. Orton
08/30/2016
... WATER TABLE OR SEEPAGE
DEPTH
IN
FEET
0
2
4
6
8
10 RESISTANCEDRY DENSITYELEV. (MSL.)
EQUIPMENT
BORING B-10
... CHUNK SAMPLE
NOTE:
PROJECT NO.
THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED. IT
IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
T2719-22-01
APPENDIX B
Geocon Project No. T2719-22-02 -B-1- February 22, 2022
APPENDIX B
LABORATORY TESTING
Laboratory tests were performed in accordance with generally accepted test methods of the
“American Society for Testing and Materials (ASTM)”, or other suggested procedures.
Selected samples were tested for maximum dry density and optimum moisture content, corrosivity,
Atterberg limits, consolidation, expansion characteristics, grain size analysis, direct shear strength,
and in-place dry density and moisture content. The results of the laboratory tests are summarized
herein. The in-place dry density and moisture content of the samples tested are presented on the
boring logs in Appendix A.
Project No.: T2719-22-02
D60 D30 D10
0.2 0.073 0.073
SAMPLE
P-1@5'
CLASSIFICATION
Silty SAND (SM), Grayish Brown
Checked by:
GRAIN SIZE DISTRIBUTION APN 371-150-001 & -002
Grand Ave. & Kathryn Way
Lake Elsinore, CAASTM D-422
Feb 22 Figure B1
3"1½"¾"⅜"#4 #10 #20 #40 #100 #200
0
10
20
30
40
50
60
70
80
90
100
0.0010.010.1110100PERCENT PASSSING BY WEIGHTGRAIN DIAMETER, mm
U.S. STANDARD SIEVE SIZES
GRAVEL
COARSE FINE
SAND
COARSE MEDIUM FINE
SILT AND CLAY
Project No.: T2719-22-02
D60 D30 D10
0.33 0.073 0.073
SAMPLE
P-2@5'
CLASSIFICATION
Silty SAND (SM), Grayish Brown
Checked by:
GRAIN SIZE DISTRIBUTION APN 371-150-001 & -002
Grand Ave. & Kathryn Way
Lake Elsinore, CAASTM D-422
Feb 22 Figure B2
3"1½"¾"⅜"#4 #10 #20 #40 #100 #200
0
10
20
30
40
50
60
70
80
90
100
0.0010.010.1110100PERCENT PASSSING BY WEIGHTGRAIN DIAMETER, mm
U.S. STANDARD SIEVE SIZES
GRAVEL
COARSE FINE
SAND
COARSE MEDIUM FINE
SILT AND CLAY
Project No.: T2719-22-02
D60 D30 D10
0.28 0.073 0.073
SAMPLE
P-3@5'
CLASSIFICATION
Silty SAND (SM), Grayish Brown
Checked by:
GRAIN SIZE DISTRIBUTION APN 371-150-001 & -002
Grand Ave. & Kathryn Way
Lake Elsinore, CAASTM D-422
Feb 22 Figure B3
3"1½"¾"⅜"#4 #10 #20 #40 #100 #200
0
10
20
30
40
50
60
70
80
90
100
0.0010.010.1110100PERCENT PASSSING BY WEIGHTGRAIN DIAMETER, mm
U.S. STANDARD SIEVE SIZES
GRAVEL
COARSE FINE
SAND
COARSE MEDIUM FINE
SILT AND CLAY
Project No.: T2719-22-02
D60 D30 D10
0.089 0.073 0.073
SAMPLE
P-4@5'
CLASSIFICATION
Silty SAND (SM), Grayish Brown
Checked by:
GRAIN SIZE DISTRIBUTION APN 371-150-001 & -002
Grand Ave. & Kathryn Way
Lake Elsinore, CAASTM D-422
Feb 22 Figure B4
3"1½"¾"⅜"#4 #10 #20 #40 #100 #200
0
10
20
30
40
50
60
70
80
90
100
0.0010.010.1110100PERCENT PASSSING BY WEIGHTGRAIN DIAMETER, mm
U.S. STANDARD SIEVE SIZES
GRAVEL
COARSE FINE
SAND
COARSE MEDIUM FINE
SILT AND CLAY
LABORATORY TEST RESULTS
GRAND AVE. AT KATHRYN WAY
LAKE ELSINORE, CALIFORNIA
FEB. 2022 PROJECT NO. T2719-22-02 FIG B-5AMO
SUMMARY OF LABORATORY MAXIMUM DRY DENSITY
AND OPTIMUM MOISTURE CONTENT TEST RESULTS
ASTM D1557
Sample No. Description
Maximum
Dry Density
(pcf)
Optimum
Moisture Content
(% of dry wt.)
B-3 @ 0-5’ Silty SAND (SM), blackish dark brown 131.0 7.5
B-6 @ 0-5’ Silty SAND (SM), gray 120.0 11.0
T-5 @ 3-5’ Silty SAND to Sandy SILT (SM/ML), dark
grayish brown to olive 128.0 10.0
SUMMARY OF CORROSIVITY TEST RESULTS
Sample No. Chloride Content
(ppm)
Sulfate Content
(%) pH Resistivity
(ohm-centimeter)
B-3 @ 0-5’ 35 0.001 7.5 7,000
Chloride content determined by California Test 422.
Water-soluble sulfate determined by California Test 417.
Resistivity and pH determined by Caltrans Test 643.
SUMMARY OF ATTERBERG LIMIT TEST RESULTS
ASTM D4318
Sample No. Liquid Limit Plastic Limit Plasticity Index USCS
B-1 @ 12.5’ 21 20 1 ML
B-1 @ 17.5’ 20 17 3 ML
B-1 @ 30’ 26 19 7 CL-ML
B-1 @ 32.5 23 18 5 ML
B-1 @ 40’ 20 20 0 ML
LABORATORY TEST RESULTS
GRAND AVE. AT KATHRYN WAY
LAKE ELSINORE, CALIFORNIA
FEB. 2022 PROJECT NO. T2719-22-02 FIG B-6AMO
SUMMARY OF ONE-DIMENSIONAL CONSOLIDATION (COLLAPSE) TESTS
ASTM D2435
Sample No. Geologic
Origin
In-situ Dry
Density
(pcf)
Moisture
Content
Before Test
(%)
Final
Moisture
Content (%)
Axial Load
with Water
Added (psf)
Percent
Collapse
B-1 @ 2.5’ afu 101.1 7.0 29.0 2,000 2.3
B-1 @ 20 Qyf 109.6 20.7 100.0 2,000 -0.1
B-1 @ 25’ Qyf 121.3 14.4 100.0 2,000 0.0
B-2 @ 2.5’ afu 118.2 4.7 31.2 2,000 1.5
B-3 @ 7.5’ Qyf 123.4 5.1 39.3 2,000 1.3
B-3 @ 12.5’ Qyf 112.1 5.3 29.3 2,000 1.3
B-5 @ 7.5’ Ql 94.1 23.8 82.9 2,000 -0.1
B-6 @ 12.5’ Qyf 112.0 18.2 100.0 2,000 0.0
B-8 @ 2.5’ afu 93.0 15.1 24.9 2,000 1.1
B-8 @ 5’ afu 100.3 10.8 18.7 2,000 1.5
B-8 @ 7.5’ afu 98.9 8.5 16.6 2,000 2.6
B-8 @ 10’ Ql 104.0 13.5 17.0 2,000 0.6
B-8 @ 15’ Ql 107.2 18.3 17.7 2,000 0.1
B-8 @ 20’ Ql 117.4 13.8 13.6 3,000 0.4
B-8 @ 25’ Ql 105.8 19.3 17.6 3,000 0.1
B-11 @ 5’ afu 98.5 8.9 20.2 2,000 -2.5
B-11 @ 15’ Qyf 107.0 9.9 16.5 2,000 -2.0
B-12 @ 10’ afu 112.2 17.5 17.2 2,000 0
B-12 @ 15’ Ql 111.7 22.8 24.1 2,000 -0.1
B-12 @ 20’ Ql 110.4 19.8 18.4 2,000 0
T-5 @ 3’ afu 114.2 3.4 13.5 2,000 1.5
T-5 @ 14’ Ql 89.6 10.0 19.0 2,000 11.8
T-6 @ 16’ Ql 112.4 7.7 17.4 2,000 0.7
LABORATORY TEST RESULTS
GRAND AVE. AT KATHRYN WAY
LAKE ELSINORE, CALIFORNIA
FEB. 2022 PROJECT NO. T2719-22-02 FIG B-7AMO
SUMMARY OF LABORATORY EXPANSION INDEX TEST RESULTS
ASTM D4829
Sample No.
Moisture Content After Test
Dry Density
(pcf)
Expansion
Index Before Test (%) After Test (%)
B-3 @ 0-5’ 8.4 13.3 115.8 3
B-6 @ 0-5’ 10.8 20.8 104.7 3
B-11 @ 0-5’ 10.5 20.2 105.9 15
CONSOLIDATION TEST RESULTS
WATER ADDED AT 2 KSF
4
2
0
Percent ConsolidationB1@2½'
6
8
4
2
0 B2@2½'
6
8
4
2
0 B5@2½'
6
8
Consolidation Pressure (KSF)
.1 .2 .3 .4 .5 .6 .7 .8 .9 1.0 2 345 6 10789
Drafted by: RDG Checked by: HHD FIG. B-9PROJECT NO. T2719-22-02FEB. 2022
LAKE ELSINORE, CALIFORNIA
GRAND AVE. AT KATHRYN WAY
PHONE (951) 304-2300 - FAX (951) 304-2392
41571 CORNING PLACE, SUITE 101, MURRIETA, CA 92562
ENVIRONMENTAL GEOTECHNICAL MATERIALS
CONSOLIDATION TEST RESULTS
WATER ADDED AT 2 KSF
4
2
0
Percent ConsolidationB3@7½'
6
8
4
2
0 B5@7½'
6
8
4
2
0 B3@12½'
6
8
Consolidation Pressure (KSF)
.1 .2 .3 .4 .5 .6 .7 .8 .9 1.0 2 345 6 10789
Drafted by: RDG Checked by: HHD FIG. B-10PROJECT NO. T2719-22-02FEB. 2022
LAKE ELSINORE, CALIFORNIA
GRAND AVE. AT KATHRYN WAY
PHONE (951) 304-2300 - FAX (951) 304-2392
41571 CORNING PLACE, SUITE 101, MURRIETA, CA 92562
ENVIRONMENTAL GEOTECHNICAL MATERIALS
CONSOLIDATION TEST RESULTS
WATER ADDED AT 2 KSF
4
2
0
Percent ConsolidationB6@12½'
6
8
4
2
0 B1@20'
6
8
4
2
0 B1@25'
6
8
Consolidation Pressure (KSF)
.1 .2 .3 .4 .5 .6 .7 .8 .9 1.0 2 345 6 10789
Drafted by: RDG Checked by: HHD FIG. B-11PROJECT NO. T2719-22-02FEB. 2022
LAKE ELSINORE, CALIFORNIA
GRAND AVE. AT KATHRYN WAY
PHONE (951) 304-2300 - FAX (951) 304-2392
41571 CORNING PLACE, SUITE 101, MURRIETA, CA 92562
ENVIRONMENTAL GEOTECHNICAL MATERIALS
SAMPLE INITIAL DRY INITIAL FINAL C
ID DENSITY (pcf) MOISTURE (%) MOISTURE (%) (psf) (deg)
B-2 @ 2.5' SM 111.1 6.1 15.3 140 35
*B-3 @ 0-5' SM 114.7 9.6 15.1 170 37
*B-6 @ 0-5' SM 104.2 13.9 21.4 220 33
*Sample remolded to approximately 90% of the test maximum dry density at optimum moisture content.
SOIL TYPE
DIRECT SHEAR TEST RESULTS
GRAND AVE. AT KATHRYN WAY
ELSINORE, CALIFORNIA
FEB. 2022 PROJECT NO. T2719-22-02 FIG B-16AMO
0
1000
2000
3000
4000
5000
0 1000 2000 3000 4000 5000Shear Stress (psf)Normal Stress (psf)
SAMPLE INITIAL DRY INITIAL FINAL C
ID DENSITY (pcf) MOISTURE (%) MOISTURE (%) (psf) (deg)
B-6 @ 2.5' SM 96.5 6.9 24.8 220 31
B-11 @ 10' SM 109.5 19.0 19.8 460 33
B-12 @ 5' SM 107.6 14.9 22.2 570 36
*Sample remolded to approximately 90% of the test maximum dry density at optimum moisture content.
SOIL TYPE
DIRECT SHEAR TEST RESULTS
GRAND AVE. AT KATHRYN WAY
ELSINORE, CALIFORNIA
FEB. 2022 PROJECT NO. T2719-22-02 FIG B-17AMO
0
1000
2000
3000
4000
5000
0 1000 2000 3000 4000 5000Shear Stress (psf)Normal Stress (psf)
APPENDIX C
Geocon Project No. T2719-22-02 - C-1 - February 22, 2022
APPENDIX C
RECOMMENDED GRADING SPECIFICATIONS
FOR
BUILDER’S MAX
APN 371-150-001 & 371-150-002
GRAND AVENUE AT KATHRYN WAY
LAKE ELSINORE, CALIFORNIA
PROJECT NO. T2719-22-02
GI rev. 07/2015
RECOMMENDED GRADING SPECIFICATIONS
1. GENERAL
1.1 These Recommended Grading Specifications shall be used in conjunction with the
Geotechnical Report for the project prepared by Geocon. The recommendations contained
in the text of the Geotechnical Report are a part of the earthwork and grading specifications
and shall supersede the provisions contained hereinafter in the case of conflict.
1.2 Prior to the commencement of grading, a geotechnical consultant (Consultant) shall be
employed for the purpose of observing earthwork procedures and testing the fills for
substantial conformance with the recommendations of the Geotechnical Report and these
specifications. The Consultant should provide adequate testing and observation services so
that they may assess whether, in their opinion, the work was performed in substantial
conformance with these specifications. It shall be the responsibility of the Contractor to
assist the Consultant and keep them apprised of work schedules and changes so that
personnel may be scheduled accordingly.
1.3 It shall be the sole responsibility of the Contractor to provide adequate equipment and
methods to accomplish the work in accordance with applicable grading codes or agency
ordinances, these specifications and the approved grading plans. If, in the opinion of the
Consultant, unsatisfactory conditions such as questionable soil materials, poor moisture
condition, inadequate compaction, and/or adverse weather result in a quality of work not in
conformance with these specifications, the Consultant will be empowered to reject the
work and recommend to the Owner that grading be stopped until the unacceptable
conditions are corrected.
2. DEFINITIONS
2.1 Owner shall refer to the owner of the property or the entity on whose behalf the grading
work is being performed and who has contracted with the Contractor to have grading
performed.
2.2 Contractor shall refer to the Contractor performing the site grading work.
2.3 Civil Engineer or Engineer of Work shall refer to the California licensed Civil Engineer
or consulting firm responsible for preparation of the grading plans, surveying and verifying
as-graded topography.
2.4 Consultant shall refer to the soil engineering and engineering geology consulting firm
retained to provide geotechnical services for the project.
GI rev. 07/2015
2.5 Soil Engineer shall refer to a California licensed Civil Engineer retained by the Owner,
who is experienced in the practice of geotechnical engineering. The Soil Engineer shall be
responsible for having qualified representatives on-site to observe and test the Contractor's
work for conformance with these specifications.
2.6 Engineering Geologist shall refer to a California licensed Engineering Geologist retained
by the Owner to provide geologic observations and recommendations during the site
grading.
2.7 Geotechnical Report shall refer to a soil report (including all addenda) which may include
a geologic reconnaissance or geologic investigation that was prepared specifically for the
development of the project for which these Recommended Grading Specifications are
intended to apply.
3. MATERIALS
3.1 Materials for compacted fill shall consist of any soil excavated from the cut areas or
imported to the site that, in the opinion of the Consultant, is suitable for use in construction
of fills. In general, fill materials can be classified as soil fills, soil-rock fills or rock fills, as
defined below.
3.1.1 Soil fills are defined as fills containing no rocks or hard lumps greater than
12 inches in maximum dimension and containing at least 40 percent by weight of
material smaller than ¾ inch in size.
3.1.2 Soil-rock fills are defined as fills containing no rocks or hard lumps larger than
4 feet in maximum dimension and containing a sufficient matrix of soil fill to allow
for proper compaction of soil fill around the rock fragments or hard lumps as
specified in Paragraph 6.2. Oversize rock is defined as material greater than
12 inches.
3.1.3 Rock fills are defined as fills containing no rocks or hard lumps larger than 3 feet
in maximum dimension and containing little or no fines. Fines are defined as
material smaller than ¾ inch in maximum dimension. The quantity of fines shall be
less than approximately 20 percent of the rock fill quantity.
3.2 Material of a perishable, spongy, or otherwise unsuitable nature as determined by the
Consultant shall not be used in fills.
3.3 Materials used for fill, either imported or on-site, shall not contain hazardous materials as
defined by the California Code of Regulations, Title 22, Division 4, Chapter 30, Articles 9
GI rev. 07/2015
and 10; 40CFR; and any other applicable local, state or federal laws. The Consultant shall
not be responsible for the identification or analysis of the potential presence of hazardous
materials. However, if observations, odors or soil discoloration cause Consultant to suspect
the presence of hazardous materials, the Consultant may request from the Owner the
termination of grading operations within the affected area. Prior to resuming grading
operations, the Owner shall provide a written report to the Consultant indicating that the
suspected materials are not hazardous as defined by applicable laws and regulations.
3.4 The outer 15 feet of soil-rock fill slopes, measured horizontally, should be composed of
properly compacted soil fill materials approved by the Consultant. Rock fill may extend to
the slope face, provided that the slope is not steeper than 2:1 (horizontal:vertical) and a soil
layer no thicker than 12 inches is track-walked onto the face for landscaping purposes. This
procedure may be utilized provided it is acceptable to the governing agency, Owner and
Consultant.
3.5 Samples of soil materials to be used for fill should be tested in the laboratory by the
Consultant to determine the maximum density, optimum moisture content, and, where
appropriate, shear strength, expansion, and gradation characteristics of the soil.
3.6 During grading, soil or groundwater conditions other than those identified in the
Geotechnical Report may be encountered by the Contractor. The Consultant shall be
notified immediately to evaluate the significance of the unanticipated condition
4. CLEARING AND PREPARING AREAS TO BE FILLED
4.1 Areas to be excavated and filled shall be cleared and grubbed. Clearing shall consist of
complete removal above the ground surface of trees, stumps, brush, vegetation, man-made
structures, and similar debris. Grubbing shall consist of removal of stumps, roots, buried
logs and other unsuitable material and shall be performed in areas to be graded. Roots and
other projections exceeding 1½ inches in diameter shall be removed to a depth of 3 feet
below the surface of the ground. Borrow areas shall be grubbed to the extent necessary to
provide suitable fill materials.
4.2 Asphalt pavement material removed during clearing operations should be properly
disposed at an approved off-site facility or in an acceptable area of the project evaluated by
Geocon and the property owner. Concrete fragments that are free of reinforcing steel may
be placed in fills, provided they are placed in accordance with Section 6.2 or 6.3 of this
document.
GI rev. 07/2015
4.3 After clearing and grubbing of organic matter and other unsuitable material, loose or
porous soils shall be removed to the depth recommended in the Geotechnical Report. The
depth of removal and compaction should be observed and approved by a representative of
the Consultant. The exposed surface shall then be plowed or scarified to a minimum depth
of 6 inches and until the surface is free from uneven features that would tend to prevent
uniform compaction by the equipment to be used.
4.4 Where the slope ratio of the original ground is steeper than 5:1 (horizontal:vertical), or
where recommended by the Consultant, the original ground should be benched in
accordance with the following illustration.
TYPICAL BENCHING DETAIL
Remove All
Unsuitable Material
As Recommended By
Consultant
Finish Grade Original Ground
Finish Slope Surface
Slope To Be Such That
Sloughing Or Sliding
Does Not Occur Varies
“B”
See Note 1
No Scale
See Note 2
1
2
DETAIL NOTES: (1) Key width "B" should be a minimum of 10 feet, or sufficiently wide to permit
complete coverage with the compaction equipment used. The base of the key should
be graded horizontal, or inclined slightly into the natural slope.
(2) The outside of the key should be below the topsoil or unsuitable surficial material
and at least 2 feet into dense formational material. Where hard rock is exposed in the
bottom of the key, the depth and configuration of the key may be modified as
approved by the Consultant.
4.5 After areas to receive fill have been cleared and scarified, the surface should be moisture
conditioned to achieve the proper moisture content, and compacted as recommended in
Section 6 of these specifications.
GI rev. 07/2015
5. COMPACTION EQUIPMENT
5.1 Compaction of soil or soil-rock fill shall be accomplished by sheepsfoot or segmented-steel
wheeled rollers, vibratory rollers, multiple-wheel pneumatic-tired rollers, or other types of
acceptable compaction equipment. Equipment shall be of such a design that it will be
capable of compacting the soil or soil-rock fill to the specified relative compaction at the
specified moisture content.
5.2 Compaction of rock fills shall be performed in accordance with Section 6.3.
6. PLACING, SPREADING AND COMPACTION OF FILL MATERIAL
6.1 Soil fill, as defined in Paragraph 3.1.1, shall be placed by the Contractor in accordance with
the following recommendations:
6.1.1 Soil fill shall be placed by the Contractor in layers that, when compacted, should
generally not exceed 8 inches. Each layer shall be spread evenly and shall be
thoroughly mixed during spreading to obtain uniformity of material and moisture
in each layer. The entire fill shall be constructed as a unit in nearly level lifts. Rock
materials greater than 12 inches in maximum dimension shall be placed in
accordance with Section 6.2 or 6.3 of these specifications.
6.1.2 In general, the soil fill shall be compacted at a moisture content at or above the
optimum moisture content as determined by ASTM D 1557.
6.1.3 When the moisture content of soil fill is below that specified by the Consultant,
water shall be added by the Contractor until the moisture content is in the range
specified.
6.1.4 When the moisture content of the soil fill is above the range specified by the
Consultant or too wet to achieve proper compaction, the soil fill shall be aerated by
the Contractor by blading/mixing, or other satisfactory methods until the moisture
content is within the range specified.
6.1.5 After each layer has been placed, mixed, and spread evenly, it shall be thoroughly
compacted by the Contractor to a relative compaction of at least 90 percent.
Relative compaction is defined as the ratio (expressed in percent) of the in-place
dry density of the compacted fill to the maximum laboratory dry density as
determined in accordance with ASTM D 1557. Compaction shall be continuous
over the entire area, and compaction equipment shall make sufficient passes so that
the specified minimum relative compaction has been achieved throughout the
entire fill.
GI rev. 07/2015
6.1.6 Where practical, soils having an Expansion Index greater than 50 should be placed
at least 3 feet below finish pad grade and should be compacted at a moisture
content generally 2 to 4 percent greater than the optimum moisture content for the
material.
6.1.7 Properly compacted soil fill shall extend to the design surface of fill slopes. To
achieve proper compaction, it is recommended that fill slopes be over-built by at
least 3 feet and then cut to the design grade. This procedure is considered
preferable to track-walking of slopes, as described in the following paragraph.
6.1.8 As an alternative to over-building of slopes, slope faces may be back-rolled with a
heavy-duty loaded sheepsfoot or vibratory roller at maximum 4-foot fill height
intervals. Upon completion, slopes should then be track-walked with a D-8 dozer
or similar equipment, such that a dozer track covers all slope surfaces at least
twice.
6.2 Soil-rock fill, as defined in Paragraph 3.1.2, shall be placed by the Contractor in accordance
with the following recommendations:
6.2.1 Rocks larger than 12 inches but less than 4 feet in maximum dimension may be
incorporated into the compacted soil fill, but shall be limited to the area measured
15 feet minimum horizontally from the slope face and 5 feet below finish grade or
3 feet below the deepest utility, whichever is deeper.
6.2.2 Rocks or rock fragments up to 4 feet in maximum dimension may either be
individually placed or placed in windrows. Under certain conditions, rocks or rock
fragments up to 10 feet in maximum dimension may be placed using similar
methods. The acceptability of placing rock materials greater than 4 feet in
maximum dimension shall be evaluated during grading as specific cases arise and
shall be approved by the Consultant prior to placement.
6.2.3 For individual placement, sufficient space shall be provided between rocks to allow
for passage of compaction equipment.
6.2.4 For windrow placement, the rocks should be placed in trenches excavated in
properly compacted soil fill. Trenches should be approximately 5 feet wide and
4 feet deep in maximum dimension. The voids around and beneath rocks should be
filled with approved granular soil having a Sand Equivalent of 30 or greater and
should be compacted by flooding. Windrows may also be placed utilizing an
"open-face" method in lieu of the trench procedure, however, this method should
first be approved by the Consultant.
GI rev. 07/2015
6.2.5 Windrows should generally be parallel to each other and may be placed either
parallel to or perpendicular to the face of the slope depending on the site geometry.
The minimum horizontal spacing for windrows shall be 12 feet center-to-center
with a 5-foot stagger or offset from lower courses to next overlying course. The
minimum vertical spacing between windrow courses shall be 2 feet from the top of
a lower windrow to the bottom of the next higher windrow.
6.2.6 Rock placement, fill placement and flooding of approved granular soil in the
windrows should be continuously observed by the Consultant.
6.3 Rock fills, as defined in Section 3.1.3, shall be placed by the Contractor in accordance with
the following recommendations:
6.3.1 The base of the rock fill shall be placed on a sloping surface (minimum slope of 2
percent). The surface shall slope toward suitable subdrainage outlet facilities. The
rock fills shall be provided with subdrains during construction so that a hydrostatic
pressure buildup does not develop. The subdrains shall be permanently connected
to controlled drainage facilities to control post-construction infiltration of water.
6.3.2 Rock fills shall be placed in lifts not exceeding 3 feet. Placement shall be by rock
trucks traversing previously placed lifts and dumping at the edge of the currently
placed lift. Spreading of the rock fill shall be by dozer to facilitate seating of the
rock. The rock fill shall be watered heavily during placement. Watering shall
consist of water trucks traversing in front of the current rock lift face and spraying
water continuously during rock placement. Compaction equipment with
compactive energy comparable to or greater than that of a 20-ton steel vibratory
roller or other compaction equipment providing suitable energy to achieve the
required compaction or deflection as recommended in Paragraph 6.3.3 shall be
utilized. The number of passes to be made should be determined as described in
Paragraph 6.3.3. Once a rock fill lift has been covered with soil fill, no additional
rock fill lifts will be permitted over the soil fill.
6.3.3 Plate bearing tests, in accordance with ASTM D 1196, may be performed in both
the compacted soil fill and in the rock fill to aid in determining the required
minimum number of passes of the compaction equipment. If performed, a
minimum of three plate bearing tests should be performed in the properly
compacted soil fill (minimum relative compaction of 90 percent). Plate bearing
tests shall then be performed on areas of rock fill having two passes, four passes
and six passes of the compaction equipment, respectively. The number of passes
required for the rock fill shall be determined by comparing the results of the plate
bearing tests for the soil fill and the rock fill and by evaluating the deflection
GI rev. 07/2015
variation with number of passes. The required number of passes of the compaction
equipment will be performed as necessary until the plate bearing deflections are
equal to or less than that determined for the properly compacted soil fill. In no case
will the required number of passes be less than two.
6.3.4 A representative of the Consultant should be present during rock fill operations to
observe that the minimum number of “passes” have been obtained, that water is
being properly applied and that specified procedures are being followed. The actual
number of plate bearing tests will be determined by the Consultant during grading.
6.3.5 Test pits shall be excavated by the Contractor so that the Consultant can state that,
in their opinion, sufficient water is present and that voids between large rocks are
properly filled with smaller rock material. In-place density testing will not be
required in the rock fills.
6.3.6 To reduce the potential for “piping” of fines into the rock fill from overlying soil
fill material, a 2-foot layer of graded filter material shall be placed above the
uppermost lift of rock fill. The need to place graded filter material below the rock
should be determined by the Consultant prior to commencing grading. The
gradation of the graded filter material will be determined at the time the rock fill is
being excavated. Materials typical of the rock fill should be submitted to the
Consultant in a timely manner, to allow design of the graded filter prior to the
commencement of rock fill placement.
6.3.7 Rock fill placement should be continuously observed during placement by the
Consultant.
7. SUBDRAINS
7.1 The geologic units on the site may have permeability characteristics and/or fracture
systems that could be susceptible under certain conditions to seepage. The use of canyon
subdrains may be necessary to mitigate the potential for adverse impacts associated with
seepage conditions. Canyon subdrains with lengths in excess of 500 feet or extensions of
existing offsite subdrains should use 8-inch-diameter pipes. Canyon subdrains less than 500
feet in length should use 6-inch-diameter pipes.
GI rev. 07/2015
TYPICAL CANYON DRAIN DETAIL
7.2 Slope drains within stability fill keyways should use 4-inch-diameter (or lager) pipes.
GI rev. 07/2015
TYPICAL STABILITY FILL DETAIL
7.3 The actual subdrain locations will be evaluated in the field during the remedial grading
operations. Additional drains may be necessary depending on the conditions observed and
the requirements of the local regulatory agencies. Appropriate subdrain outlets should be
evaluated prior to finalizing 40-scale grading plans.
7.4 Rock fill or soil-rock fill areas may require subdrains along their down-slope perimeters to
mitigate the potential for buildup of water from construction or landscape irrigation. The
subdrains should be at least 6-inch-diameter pipes encapsulated in gravel and filter fabric.
Rock fill drains should be constructed using the same requirements as canyon subdrains.
GI rev. 07/2015
7.5 Prior to outletting, the final 20-foot segment of a subdrain that will not be extended during
future development should consist of non-perforated drainpipe. At the non-perforated/
perforated interface, a seepage cutoff wall should be constructed on the downslope side of
the pipe.
TYPICAL CUT OFF WALL DETAIL
7.6 Subdrains that discharge into a natural drainage course or open space area should be
provided with a permanent headwall structure.
GI rev. 07/2015
TYPICAL HEADWALL DETAIL
7.7 The final grading plans should show the location of the proposed subdrains. After
completion of remedial excavations and subdrain installation, the project civil engineer
should survey the drain locations and prepare an “as-built” map showing the drain
locations. The final outlet and connection locations should be determined during grading
operations. Subdrains that will be extended on adjacent projects after grading can be placed
on formational material and a vertical riser should be placed at the end of the subdrain. The
grading contractor should consider videoing the subdrains shortly after burial to check
proper installation and functionality. The contractor is responsible for the performance of
the drains.
GI rev. 07/2015
8. OBSERVATION AND TESTING
8.1 The Consultant shall be the Owner’s representative to observe and perform tests during
clearing, grubbing, filling, and compaction operations. In general, no more than 2 feet in
vertical elevation of soil or soil-rock fill should be placed without at least one field density
test being performed within that interval. In addition, a minimum of one field density test
should be performed for every 2,000 cubic yards of soil or soil-rock fill placed and
compacted.
8.2 The Consultant should perform a sufficient distribution of field density tests of the
compacted soil or soil-rock fill to provide a basis for expressing an opinion whether the fill
material is compacted as specified. Density tests shall be performed in the compacted
materials below any disturbed surface. When these tests indicate that the density of any
layer of fill or portion thereof is below that specified, the particular layer or areas
represented by the test shall be reworked until the specified density has been achieved.
8.3 During placement of rock fill, the Consultant should observe that the minimum number of
passes have been obtained per the criteria discussed in Section 6.3.3. The Consultant
should request the excavation of observation pits and may perform plate bearing tests on
the placed rock fills. The observation pits will be excavated to provide a basis for
expressing an opinion as to whether the rock fill is properly seated and sufficient moisture
has been applied to the material. When observations indicate that a layer of rock fill or any
portion thereof is below that specified, the affected layer or area shall be reworked until the
rock fill has been adequately seated and sufficient moisture applied.
8.4 A settlement monitoring program designed by the Consultant may be conducted in areas of
rock fill placement. The specific design of the monitoring program shall be as
recommended in the Conclusions and Recommendations section of the project
Geotechnical Report or in the final report of testing and observation services performed
during grading.
8.5 We should observe the placement of subdrains, to check that the drainage devices have
been placed and constructed in substantial conformance with project specifications.
8.6 Testing procedures shall conform to the following Standards as appropriate:
8.6.1 Soil and Soil-Rock Fills:
8.6.1.1 Field Density Test, ASTM D 1556, Density of Soil In-Place By the
Sand-Cone Method.
GI rev. 07/2015
8.6.1.2 Field Density Test, Nuclear Method, ASTM D 6938, Density of Soil and
Soil-Aggregate In-Place by Nuclear Methods (Shallow Depth).
8.6.1.3 Laboratory Compaction Test, ASTM D 1557, Moisture-Density
Relations of Soils and Soil-Aggregate Mixtures Using 10-Pound
Hammer and 18-Inch Drop.
8.6.1.4. Expansion Index Test, ASTM D 4829, Expansion Index Test.
9. PROTECTION OF WORK
9.1 During construction, the Contractor shall properly grade all excavated surfaces to provide
positive drainage and prevent ponding of water. Drainage of surface water shall be
controlled to avoid damage to adjoining properties or to finished work on the site. The
Contractor shall take remedial measures to prevent erosion of freshly graded areas until
such time as permanent drainage and erosion control features have been installed. Areas
subjected to erosion or sedimentation shall be properly prepared in accordance with the
Specifications prior to placing additional fill or structures.
9.2 After completion of grading as observed and tested by the Consultant, no further
excavation or filling shall be conducted except in conjunction with the services of the
Consultant.
10. CERTIFICATIONS AND FINAL REPORTS
10.1 Upon completion of the work, Contractor shall furnish Owner a certification by the Civil
Engineer stating that the lots and/or building pads are graded to within 0.1 foot vertically of
elevations shown on the grading plan and that all tops and toes of slopes are within 0.5 foot
horizontally of the positions shown on the grading plans. After installation of a section of
subdrain, the project Civil Engineer should survey its location and prepare an as-built plan
of the subdrain location. The project Civil Engineer should verify the proper outlet for the
subdrains and the Contractor should ensure that the drain system is free of obstructions.
10.2 The Owner is responsible for furnishing a final as-graded soil and geologic report
satisfactory to the appropriate governing or accepting agencies. The as-graded report
should be prepared and signed by a California licensed Civil Engineer experienced in
geotechnical engineering and by a California Certified Engineering Geologist, indicating
that the geotechnical aspects of the grading were performed in substantial conformance
with the Specifications or approved changes to the Specifications.