GEOTECHNICAL REPORT
PANOCHE VALLEY SOLAR FARM
SAN BENITO COUNTY, CALIFORNIA
Submitted to:
Eric Cherniss
Solargen Energy, Incorporated
2400 Stephen Creek Boulevard, Suite 700
Cupertino, CA 95014
Prepared by:
ENGEO Incorporated
March 26, 2010
Project No. 8924.000.000
.
Copyright © 2010 By ENGEO Incorporated.
This Document May Not Be Reproduced In
Whole Or In Part By Any Means
Whatsoever, Nor May It Be Quoted Or
Excerpted Without The Express Written
Consent Of ENGEO Incorporated
- Expect Excellence -
GEOTECHNICAL
ENVIRONMENTAL
WATER RESOURCES
CONSTRUCTION SERVICES
Project No.
8924.000.000
March 26, 2010
Eric Cherniss
Solargen Energy, Incorporated
2400 Stephen Creek Boulevard, Suite 700
Cupertino, CA 95014
Subject:
Panoche Valley Solar Farm
San Benito County, California
GEOTECHNICAL REPORT
Dear Mr. Cherniss:
ENGEO prepared this geotechnical report for the Panoche Valley Solar Farm as outlined in our
agreement dated February 19, 2010. We characterized the subsurface conditions at the site to
provide the enclosed geotechnical recommendations for design.
Our experience and that of our profession clearly indicates that the risk of costly design,
construction, and maintenance problems can be significantly lowered by retaining the design
geotechnical engineering firm to review the project plans and specifications and provide
geotechnical observation and testing services during construction. Please let us know when
working drawings are nearing completion, and we will be glad to discuss these additional
services with you.
If you have any questions or comments regarding this report, please call and we will be glad to
discuss them with you.
Sincerely,
ENGEO Incorporated
Paul J. Cottingham, CEG
Senior Geologist
Mark M. Gilbert, GE
Principal
Jonathan C. Boland, GE
Senior Engineer
2213 Plaza Drive Rocklin, CA 95765 (916) 786-8883 Fax (888) 279-2698
www.engeo.com
Solargen Energy, Incorporated
Panoche Valley Solar Farm
8924.000.000
March 26, 2010
TABLE OF CONTENTS
Letter of Transmittal
1.0
INTRODUCTION .........................................................................................1
1.1
1.2
1.3
2.0
FINDINGS......................................................................................................2
2.1
2.2
2.3
2.4
2.5
2.6
2.7
3.0
PURPOSE AND SCOPE .......................................................................................1
PROJECT LOCATION ........................................................................................1
PROJECT DESCRIPTION ..................................................................................2
FIELD EXPLORATION.......................................................................................2
2.1.1 Borings .........................................................................................................3
2.1.2 Electrical Resistivity Testing .......................................................................3
GEOLOGY.............................................................................................................3
2.2.1 Regional Geologic Setting ...........................................................................3
2.2.2 Geologic Mapping.........................................................................................4
SEISMICITY AND FAULTING..........................................................................5
SURFACE CONDITIONS....................................................................................5
SUBSURFACE CONDITIONS ............................................................................7
GROUNDWATER CONDITIONS......................................................................8
LABORATORY TESTING ..................................................................................8
CONCLUSIONS ............................................................................................8
3.1
3.2
3.3
3.4
3.5
3.6
3.7
3.8
3.9
FOUNDATION SUPPORT...................................................................................9
SEISMIC HAZARDS ............................................................................................9
3.2.1 Ground Rupture ...........................................................................................9
3.2.2 Ground Shaking ...........................................................................................9
3.2.3 Liquefaction ...............................................................................................10
3.2.4 Ground Lurching........................................................................................10
EXPANSIVE SOIL..............................................................................................10
2007 CBC SEISMIC DESIGN PARAMETERS...............................................11
SOIL CORROSION POTENTIAL....................................................................11
CLIMATE AND FROST/HEAVE CONDITIONS ..........................................12
EXCAVATABILITY...........................................................................................12
ON-SITE AGGREGATE SOURCES ................................................................12
HORIZONTAL DIRECTIONAL DRILLING .................................................12
4.0
CONSTRUCTION MONITORING ..........................................................12
5.0
EARTHWORK RECOMMENDATIONS ................................................13
5.1
5.2
GENERAL AREA CLEARING.........................................................................13
BUILDING AND EQUIPMENT PAD OVEREXCAVATION .......................14
Solargen Energy, Incorporated
Panoche Valley Solar Farm
5.3
5.4
5.5
5.6
6.0
6.2
7.2
INTERIOR CONCRETE FLOOR SLABS.......................................................20
7.1.1 Minimum Design Section ..........................................................................20
7.1.2 Slab Moisture Vapor Reduction.................................................................20
7.1.3 Subgrade Modulus for Structural Slab Design – Equipment Pads ............21
TRENCH BACKFILL.........................................................................................21
PAVEMENT DESIGN.................................................................................21
8.1
8.2
8.3
8.4
9.0
PILE FOUNDATIONS........................................................................................16
6.1.1 Lateral Pile Capacity..................................................................................16
6.1.2 Vertical Pile Capacity ................................................................................18
CONVENTIONAL FOOTINGS WITH SLAB-ON-GRADE .........................18
6.2.1 Footing Dimensions and Allowable Bearing Capacity..............................18
6.2.2 Reinforcement............................................................................................19
6.2.3 Foundation Lateral Resistance ...................................................................19
6.2.4 Settlement ..................................................................................................19
SLABS-ON-GRADE ...................................................................................20
7.1
8.0
ACCEPTABLE FILL..........................................................................................14
OVER-OPTIMUM SOIL MOISTURE CONDITIONS ..................................14
FILL COMPACTION .........................................................................................15
5.5.1 Grading in Structural Areas .......................................................................15
5.5.2 Underground Utility Backfill in Structural Areas ......................................15
5.5.3 Underground Utility Backfill in Non-Structural Areas..............................16
SLOPES GRADIENTS .......................................................................................16
FOUNDATION RECOMMENDATIONS ................................................16
6.1
7.0
8924.000.000
March 26, 2010
FLEXIBLE PAVEMENTS .................................................................................21
AGGREGATE ROADS.......................................................................................22
SUBGRADE AND AGGREGATE BASE COMPACTION ............................22
CHEMICALLY TREATED SUBGRADE ........................................................22
LIMITATIONS AND UNIFORMITY OF CONDITIONS......................23
FIGURES
Figure 1:
Figure 2:
Figure 3:
Figure 4:
Figure 5:
Figure 6:
Vicinity Map
Regional Faulting and Seismicity
Site Plan
Franciscan Alluvial Fan Borings
Panoche Alluvial Fan Borings
Fluvial Deposit Borings
APPENDIX A – Exploration Logs
APPENDIX B – Laboratory Test Data
APPENDIX C – NORCAL Geophysical Test Data
Solargen Energy, Incorporated
Panoche Valley Solar Farm
1.0
INTRODUCTION
1.1
PURPOSE AND SCOPE
8924.000.000
March 26, 2010
ENGEO prepared this geotechnical report for design of the Panoche Valley Solar Farm in San
Benito County, California. We prepared this report as outlined in our agreement dated February 19,
2010. Solargen Energy authorized ENGEO to conduct the scope of services outlined below:
•
•
•
•
•
Service Plan Development
Subsurface Field Exploration
Soil Laboratory Testing
Data Analysis and Conclusions
Report Preparation.
For our use, we received the following:
1. RFQ, POWER Engineers, delivered via email on February 4, 2010.
2. Electronic site plan, POWER Engineers, delivered via email on March 2, 2010.
3. Panoche Valley Solar Farm Initial Study, POWER Engineers, dated August 2009.
This report was prepared for the exclusive use of our client and their consultants for design of
this project. In the event that any changes are made in the character, design or layout of the
improvements, we must be contacted to review the conclusions and recommendations contained
in this report to determine whether modifications are necessary. This document may not be
reproduced in whole or in part by any means whatsoever, nor may it be quoted or excerpted
without our express written consent.
1.2
PROJECT LOCATION
Figure 1 displays a Site Vicinity Map. The
site is located in Panoche Valley situated in
the Coast Ranges approximately 43 miles
southeast of Hollister via Panoche Road and
approximately 16 miles west of Interstate 5
via West Panoche Road.
Figure 2 shows site boundaries, proposed
improvement areas, geology, as well as our
exploratory locations. The 5000-acre site
occupies the majority of the Panoche Valley
north of Panoche Road. Little Panoche Road
trends north-south bisecting the site. The site
Panoche Valley, looking northwest
is generally bordered by mountains to the east
and west. The southern portion of the site is generally bordered by flat cattle grazing land.
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Solargen Energy, Incorporated
Panoche Valley Solar Farm
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March 26, 2010
Panoche Creek cuts through the southern portion of the site. Los Aguilas Creek enters the
western portion of the site and joins with Panoche Creek near the southern boundary.
Additionally, an unnamed creek cuts through the very southeastern corner of the site.
1.3
PROJECT DESCRIPTION
We understand the proposed solar farm will include:
•
•
•
•
•
140 to 230 Watt photovoltaic panel arrays
Equipment pads including: 1000 kVA transformers and 500kW inverters
Substation
Electric Transmission Cable
Access roads
We understand the photovoltaic arrays will likely be supported on steel pipe piles, H-Piles, or
precast concrete piles. The photovoltaic panel arrays are divided into a total of 210 blocks. Each
block will include photovoltaic panel strings, two transformers, and four inverters. The
equipment pads with the transformers and inverters will likely be constructed on mat type
foundation. The substation, also referred to as the switchyard, will house large transformers and
switchgear and will also include an operation and maintenance facility.
It is expected that grading will only be necessary for the substation, equipment pads for
transformers and inverters within each block, and access roads.
2.0
FINDINGS
2.1
FIELD EXPLORATION
Our field exploration included two phases of drilling totaling 22 borings as well as performing 7
electrical resistivity surveys at various locations on site. We performed the first phase of our field
exploration on March 8th and 9th 2010; the second phase of exploration occurred on March 16th
and 17th 2010. We also performed geologic field mapping concurrently.
The location and elevations of our explorations are approximate and were determined using a
hand held GPS device; they should be considered accurate only to the degree implied by the
method used. We describe our exploration techniques below.
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2.1.1
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March 26, 2010
Borings
We observed drilling of 22 borings and logged the subsurface conditions at each location. Boring
locations are shown on Site Plan, Figure 3. We retained a Mobile B24 drill rig and crew to advance
the borings using 4-inch diameter solid flight auger methods. Borings were advanced to depths
ranging from 15 to 51½ feet below existing grade. Borings were backfilled with drill cuttings.
We obtained soil samples at various intervals using standard penetration tests and a California
Modified Sampler (3-inch O.D. split spoon with 2.5-inch I.D. liners). The blow counts were
obtained by dropping a 140-pound hammer through a 30-inch free fall. The sampler was driven
18 inches and the number of blows were recorded for each 6 inches of penetration. Unless
otherwise indicated, the blows per foot recorded on the boring log represent the accumulated
number of blows required to drive the last 1 foot of penetration; the blow counts have not been
converted using any correction factors. When sampler driving was difficult, penetration was
recorded only as inches penetrated for 50 hammer blows.
We used the field logs to develop the report logs in Appendix A. The logs depict subsurface
conditions at the exploration locations for the date of exploration; however, subsurface
conditions may vary with time.
2.1.2
Electrical Resistivity Testing
We retained NORCAL Geophysical Consultants to perform electrical resistivity testing to provide
design recommendations for electrical grounding systems. Using a 2-person crew headed by a
licensed California Professional Geophysicist, they tested in seven locations to evaluate the in-situ
soil resistivity. At each location, a Wenner electrode array was used to obtain measurements
oriented in roughly east-west and north-south directions. Electrode spacings of 2, 5, 7, 10, 20, and
40 feet were used to obtain electrical resistivity measurements to a depth of about 25 feet below
grade. The data is recorded as apparent resistivity versus electrode spacing, and presented in a
tabular format. The report, attached in Appendix C, describes the method used, field procedures,
and a tabulation of the results.
2.2
GEOLOGY
2.2.1
Regional Geologic Setting
The site is located in the Coast Ranges geomorphic province, which includes many separate
ranges, coalescing mountain masses, and many structural valleys. These mountain ranges are
made up largely of marine sedimentary rocks that have been highly faulted, folded, and altered by
orogenic processes.
Panoche Valley is mapped as Quaternary Alluvium (Dibblee, Panoche Valley Quadrangle, 1975)
consisting of sediments transported by creeks and alluvial fans from the surrounding mountains.
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Panoche Valley Solar Farm
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March 26, 2010
The mountains to the east and south of the site are mapped as Panoche Formation consisting of
marine sandstone and shale. The mountains to the west are mapped as Franciscan Formation
consisting of highly sheared marine sandstone, shale and volcanics.
We have divided the Quaternary Alluvium into three major geologic units: Franciscan Alluvial
Fans, Panoche Alluvial Fans, and Fluvial Deposits. We present a detailed discussion of these
units below.
2.2.2
Geologic Mapping
An ENGEO geologist observed the geologic features at surface and reviewed aerial photographs.
We mapped the geology and summarize our major findings on the Site Plan, Figure 3.
The geomorphology of Panoche Valley suggest three major sources of alluvium: Franciscan
Alluvial Fans, Panoche Alluvial Fans, and Fluvial Deposits. Additionally, we observed areas of
young fluvial deposits in the Panoche Creek channel and young alluvial deposits in the Los
Aguilas Creek channel.
Alluvial fans are fan-shaped landforms formed by water-transported material generally deposited
where steep terrain meets a valley. Material transported in a steep gradient creek reaches a flatter
gradient and is deposited, commonly in braded streams. Material deposited in alluvial fans is
often poorly sorted and is closely related to the material in the nearby parent terrain.
Fluvial deposits are materials transported and deposited by river or creek systems. These systems
generally deposit sediments as they meander through gentle terrain. As the river or creek bends, it
erodes on its outer bank and deposits material on the inside of the bend. Material deposited in
this manner is generally coarse-grained gravel and sand. Fine-grained material, such as silt and
clay, typically get deposited when the river or creek overtops its banks and suspended fine
grained material settles out over the flood plain. This process generally results in intermittent
pockets of sand, silt, clay, and gravel.
We observed a topographic feature near the
western boundary of the site that could be
fault related. This feature, shown on Figure
3, is a linear break in slope extending
approximately 3,700 feet northeasterly. This
feature abruptly slopes down from an upper
terrace to a lower terrace; the vertical
elevation difference between the two is
approximately 10 feet.
We describe, in detail, soils of each geologic
region in Section 2.5, Subsurface Conditions.
-4-
Possible fault related topographic feature,
looking northeast downhill
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Panoche Valley Solar Farm
2.3
8924.000.000
March 26, 2010
SEISMICITY AND FAULTING
California is an active seismic region with numerous active earthquake faults. We include a
Regional Faulting and Seismicity Map as Figure 2. Nearby active faults include the Ortigalita to
the north, Great Valley to the east, and the San Andreas to the west. An active fault is defined by
the California Geologic Survey as one that has had surface displacement within the last
11,000 years (Hart, 1997).
The site is not located within a currently designated Alquist-Priolo Earthquake Fault Zone. We
used the software program EQFAULT Version 3.00b (Blake, 2000) to search a 100 km radius in
order to locate the nearest known mapped active faults and summarize them in the table below.
Table 1
Nearest Known Active Faults
Fault
Distance from Site (miles)
Ortigalita
5.7
Great Valley 10
7.9
Great Valley 9
9.9
Great Valley 11
12.2
San Andreas (Creeping)
15.6
Moment Magnitude
7.1
6.4
6.6
6.4
6.2
Although there are no known mapped active faults crossing the site, as described in Section 2.2.2
we observed a topographic feature near the western boundary of the site that could be fault
related. We provide recommendations regarding this possible fault in Section 3.2.1.
2.4
SURFACE CONDITIONS
According to the site plan provided by POWER Engineers site grades range from Elevation
1,500 feet (Datum: 0 feet = Mean Sea Level) in the southwest to Elevation 1,200 feet near the
southern boundary. The majority of the site gently slopes toward the middle and southern
portions of the site.
We observed the following site features during our reconnaissance and aerial photograph review:
•
The ground surface was generally covered with short grass and was being active used for
cattle grazing. A multitude of fences divide up the site into separate cattle pastures.
•
Relatively few structures are located on the site. Most of the structures appeared related to
livestock operations, however one residential dwelling was located near the southern
boundary of the site.
•
Wells related to livestock operations are scattered throughout the site.
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•
As described above, we observed a topographic feature near the western boundary of the site
that could be fault related.
•
Existing overhead transmission lines cross the site trending approximately northwestsoutheast.
•
Panoche Creek – Panoche Creek
meanders through the southern portion of
the site. The creek generally appears
confined to a relatively narrow channel
and dense older deposit were frequently
apparent in the creek banks. The banks
were generally very steep or vertical and
range from 6 to 10 feet tall and the creek
bedload consists of cobble, gravel, and
sand. Small terraces of younger deposits
generally 1 to 4 feet tall were
intermittently located inside the steep
banks, generally on the inside of a bend
Panoche Creek looking west
in the channel. In a few locations, the
geomorphology shows old creek channels outside of the current channel; this is likely due
creek meanders that have been cut off. These old channel areas and the areas inside the creek
banks are mapped as Young Fluvial Deposits (see Figure 3).
•
Los Aguilas Creek – Los Aguilas Creek
enters the site on the western boundary as
a main channel of a Franciscan Alluvial
Fan and was dry at the time of our visit.
In the western portion of the site the
channel was generally broad, shallow,
and braided in nature with gravel and
cobble bedload. This channel then
appeared subdued and then nonexistent
toward the middle of the site. The
drainage then reemerges to the south as a
narrow erosional channel with little to no
bedload and runs southeast, eventually
meeting Panoche Creek. The Los Aguilas
Creek deposits are mapped as Young
Alluvial Deposits (see Figure 3).
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Los Aguilas Creek, looking east
Solargen Energy, Incorporated
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•
Unnamed Creek – An unnamed creek trends south through the very southeastern portion of
the site and was dry at the time of our visit. This creek appeared erosive in nature and has
little bedload. A pile of metal and wood debris was located along the bank in one area.
•
Small cattle ponds in the northern portion of the site. These appear to be relatively shallow
excavations with the spoils making up a berm on the downhill side. These berms are shown
on the Figure 3 as Pond Fill.
•
Small, 1- to 3-foot deep, channels trending southwest come out of the mountains and into the
east side of the site. These channels are generally covered with grass and do no appear to
have significant recent deposits associated with them.
•
We commonly observed animal burrows
across the site. In some locations, these
were
extensive
and
significantly
disturbed the ground surface.
•
We observed isolated areas with cobble
and gravel at the ground surface
throughout the Franciscan and Panoche
Alluvial Fan geologic units.
Please refer to the Site Plan, Figure 3, for
more information on site features.
2.5
Animal Burrows, Franciscan Alluvial Fan
SUBSURFACE CONDITIONS
The explorations encountered variable soil between borings, however soil was more consistent
within individual geologic units we delineated on site. In general, soils were moist in the upper
approximately 3 feet and decreased in moisture below 3 feet. We describe the subsurface
conditions within each geologic unit below. Figures 4, 5, and 6 show borings logs grouped by
geologic region.
Franciscan Alluvial Fans
In general, within this geologic unit, borings encountered very dense clayey or silty sand with
gravel. In some areas, borings encountered very stiff silty clay with sand in the upper 3 feet.
These deposits were generally reddish in color, poorly sorted, and appeared highly weathered
with some easily-breakable gravel clasts.
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Panoche Valley Solar Farm
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March 26, 2010
Panoche Alluvial Fans
In general, within this geologic unit, borings encountered stiff to hard low to medium plasticity
silty clay with limited areas of very dense silty or clayey sands. Soil was generally olive brown or
yellowish brown in color frequently with carbonate and weak cementation.
Fluvial Deposits
In general, within this geologic unit, borings encountered variable pockets of sand, silt, clay and
gravel. We encountered fine to medium grained loose silty sand in five borings generally in the
upper 6 feet, however as deep as 13 feet in boring B-11. Deeper sand as well as gravel (boring B-9)
was generally medium dense to very dense. Clay encountered was generally stiff to hard and low to
medium plasticity. Silt encountered was generally stiff to hard and is some areas weakly cemented.
Consult the Site Plan and exploration logs for specific subsurface conditions at each location. We
include our exploration logs in Appendix A. The logs contain the soil type, color, consistency,
and visual classification in general accordance with the Unified Soil Classification System. The
logs graphically depict the subsurface conditions encountered at the time of the exploration.
Appendix A also provides additional exploratory information in the general notes to the logs.
2.6
GROUNDWATER CONDITIONS
We did not observe static groundwater in any of our subsurface explorations. We observed minor
perched water in boring B-20 at 39 feet below the ground surface. Based on available California
Department of Water Resources data, groundwater is recorded within the central portion of the
site approximately 60 to 100 feet below the ground surface.
Fluctuations in the level of groundwater may occur due to variations in rainfall, irrigation
practice, and other factors not evident at the time measurements were made.
2.7
LABORATORY TESTING
We performed laboratory tests on selected soil samples to determine their engineering properties.
For this project, we performed moisture content, dry density, unconfined compression, plasticity
index, expansion index, sieve, resistance value, thermal resistivity, and soil corrosion potential
testing. We include the majority of the laboratory test results on the borelogs in Appendix A; we
present individual test results in Appendix B.
3.0
CONCLUSIONS
From a geotechnical engineering viewpoint, in our opinion, the proposed project may be
designed as planned, provided the geotechnical recommendations in this report are properly
incorporated into the design plans and specifications. We summarize our conclusions below.
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3.1
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FOUNDATION SUPPORT
Based on our discussed with Solargen, we understand the desired foundation support type for the
solar array panels is a single driven steel pipe, steel “H” beam, or precast concrete pile. Based on
the site conditions, laboratory test data, and anticipated structural loading, it is our option that
this foundation approach is feasible. Ancillary structures, including lightly loaded buildings,
maintenance structures and offices can be supported on conventional shallow footings with slabson-grade. We recommend structural mat slabs for heavy equipment pads. Heavy loads associated
with the substation can be supported on large spread footings or structural mat foundations.
Detailed foundation recommendations for the solar arrays and lightly loaded structures are
presented in Section 6.0.
3.2
SEISMIC HAZARDS
Potential seismic hazards resulting from a nearby moderate to major earthquake can generally be
classified as primary and secondary. The primary effect is ground rupture, also called surface
faulting. The common secondary seismic hazards include ground shaking, and ground lurching.
The following sections present a discussion of these hazards as they apply to the site. Based on
topographic and lithologic data, the risk of regional subsidence or uplift, soil liquefaction, lateral
spreading, landslides, tsunamis, flooding or seiches is considered low to negligible at the site.
3.2.1
Ground Rupture
Although there are no known active faults crossing the property and the site is not located within
an Earthquake Fault Special Study Zone, it is our opinion that the topographic feature described
in Section 2.3 could possibly be fault related. Without performing additional exploration, we
recommend a set back for improvements of 50 feet from this feature. If implementing a setback
is undesirable, then trench exploration would be necessary to evaluate for evidence of faulting.
3.2.2
Ground Shaking
An earthquake of moderate to high magnitude could cause considerable ground shaking at the
site. To mitigate the shaking effects, all structures should be designed using sound engineering
judgment and the 2007 California Building Code (CBC) requirements, as a minimum. Seismic
design provisions of current building codes generally prescribe minimum lateral forces, applied
statically to the structure, combined with the gravity forces of dead-and-live loads. The codeprescribed lateral forces are generally considered to be substantially smaller than the comparable
forces that would be associated with a major earthquake. Therefore, structures should be able to:
(1) resist minor earthquakes without damage, (2) resist moderate earthquakes without structural
damage but with some nonstructural damage, and (3) resist major earthquakes without collapse
but with some structural as well as nonstructural damage. Conformance to the current building
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code recommendations does not constitute any kind of guarantee that significant structural
damage would not occur in the event of a maximum magnitude earthquake; however, it is
reasonable to expect that a well-designed and well-constructed structure will not collapse or
cause loss of life in a major earthquake (SEAOC, 1996).
3.2.3
Liquefaction
Soil liquefaction results from loss of strength during cyclic loading, such as imposed by
earthquakes. Soils most susceptible to liquefaction are clean, loose, saturated, uniformly graded,
fine-grained sands. The deep sands encountered in our borings were generally medium to very
dense. In addition, groundwater was not encountered within the 51½ foot depth of our borings.
For these reasons and based upon engineering judgment, it is our opinion that the potential for
liquefaction at the site is low during seismic shaking.
3.2.4
Ground Lurching
Ground lurching is a result of the rolling motion imparted to the ground surface during energy
released by an earthquake. Such rolling motion can cause ground cracks to form in weaker soils.
The potential for the formation of these cracks is considered greater at contacts between deep
alluvium and bedrock. Such an occurrence is possible at the site, but based on the site location, it
is our opinion that the offset is expected to be very minor.
3.3
EXPANSIVE SOIL
We observed potentially expansive clay near the ground surface in some of the borings. Our
laboratory testing indicates that these soils exhibit low to high shrink/swell potential with
variations in moisture content.
Expansive soils change in volume with changes in moisture. They can shrink or swell and cause
heaving and cracking of slabs-on-grade, and structures founded on shallow foundations.
To reduce the potential for damage to the planned improvements, we recommend that the upper
18 inches of the building and equipment pad extending at least 10 feet laterally beyond building
areas, be underlain by non-expansive fill. Due to the relatively flat nature of the site, selective
grading to mitigate expansive soil may not be a practical alternative and imported fill may be
required. In lieu of importing non-expansive fill, it may be cost effective to lime treat the upper
18 inches of the building pad to reduce the expansion potential of the on-site soil.
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3.4
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2007 CBC SEISMIC DESIGN PARAMETERS
We provide the 2007 California Building Code (CBC) seismic parameters in 2 below.
Table 2
2007 CBC
Parameter
3.5
Design Value
Site Class
0.2 second Spectral Response Acceleration, SS
1.0 second Spectral Response Acceleration, S1
Site Coefficient, FA
Site Coefficient, FV
Maximum considered earthquake spectral response accelerations for
short periods, SMS
Maximum considered earthquake spectral response accelerations
for 1-second periods, SM1
Design spectral response acceleration at short periods, SDS
D
1.49
0.48
1.0
1.52
1.49
Design spectral response acceleration at 1-second periods, SD1
Long period transition-period, TL
0.48
0.78
0.99
12
SOIL CORROSION POTENTIAL
We submitted select soil samples to an analytical lab for determination of pH, resistivity, sulfate,
and chloride. The majority of the sulfate lab test results indicate the sulfate exposure may be
categorized as “Negligible” in accordance with Table 19-A-4 of the California Building Code.
For “Negligible” sulfate exposure, the CBC indicates that either Type I or Type II Portland
Cement may be used for concrete mix designs.
One sample from boring B-14 at a depth of 4 feet, indicates the sulfate exposure may be
categorized as “Moderate” in accordance with Table 19-A-4 of the California Building Code. For
“Moderate” sulfate exposure, the CBC indicates that Type II Portland Cement with a water
content ratio of less than 0.50 may be used for concrete mix designs.
The samples tested had low resistivities, indicating that they are moderately to highly corrosive to
buried metal.
We recommend further corrosion testing be preformed to better characterize the site. We present
the analytical lab test results in Appendix B.
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CLIMATE AND FROST/HEAVE CONDITIONS
The site is in the Coast Range, inland of the coast, but has some ocean influence that keeps
temperatures from hitting more extreme highs and lows. Seasons are sharply defined with hot
and dry summers with large daily temperature swings. Winters are cool, but not severe. The
average summer high temperature in nearby Hollister is 82 degrees and an average winter high of
61 degrees. On average August is the warmest month and December is the coolest month.
Average annual rainfall is approximately 10 inches. Snow is rare, except for the higher
elevations. Due to the climate of the region and elevation of the site, we do not anticipate frost
heave affecting the proposed improvements.
3.7
EXCAVATABILITY
Based on our exploration and the geologic setting of Panoche Valley, conventional grading and
backhoe equipment will likely be able to excavate the soil deposits.
3.8
ON-SITE AGGREGATE SOURCES
We observed gravel and cobble that could potentially be suitable for on-site aggregate sources within
the portion of Los Aguilas Creek channel mapped as Young Alluvial Deposits (see Figure 2). Borings
near these deposits encountered sand with gravel within the Franciscan Alluvial Fan region, however
due to the high fines content and highly weathered nature of the material, we do not consider this
material suitable as an on-site aggregate source.
3.9
HORIZONTAL DIRECTIONAL DRILLING
We understand horizontal directional drilling may be considered for installation of underground
electrical transmission lines. Based on our subsurface exploration program, it appears that
directional drilling is a feasible construction method.
For general planning purposes we recommend using our boring logs and geologic map in this
report to anticipate subsurface conditions. However, for the purposes of developing a baseline of
anticipated subsurface conditions for bidding, we suggest you consider additional subsurface
exploration in the areas of proposed horizontal drilling.
4.0
CONSTRUCTION MONITORING
Our experience and that of our profession clearly indicates that the risk of costly design,
construction, and maintenance problems can be significantly lowered by retaining the design
geotechnical engineering firm to:
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1. Review the final grading and foundation plans and specifications prior to construction to
determine whether our recommendations have been implemented, and to provide additional
or modified recommendations, if necessary. This also allows us to check if any changes have
occurred in the nature, design or location of the proposed improvements and provides the
opportunity to prepare a written response with updated recommendations.
2. Perform construction monitoring to check the validity of the assumptions we made to prepare
this report. All earthwork operations should be performed under the observation of our
representative to check that the site is properly prepared, the selected fill materials are
satisfactory, and that placement and compaction of the fills has been performed in accordance
with our recommendations and the project specifications. Sufficient notification to us prior to
earthwork is essential.
If we are not retained to perform the services described above, then we are not responsible for
any party’s interpretation of our report (and subsequent addenda, letters, and verbal discussions).
5.0
EARTHWORK RECOMMENDATIONS
Earthwork recommendations are intended for use in structural areas that will support
improvements such as the substation, equipment pads and roads. For the solar array areas, we
understand the panels will generally follow existing topography with very little or no grading.
We define “structural areas” as any area sensitive to settlement of compacted soil. These areas
include, but are not limited to equipment pads, buildings, and pavement areas. Solar array areas
where piles will be driven into undisturbed native soils are not considered structural areas for
earthwork purposes. However, if minor grading is necessary within array areas and compacted
fill will be used to support pile foundations, then these should be considered structural areas and
the earthwork recommendations presented below would apply.
The relative compaction and optimum moisture content of soil, rock, and aggregate base referred
to in this report are based on the most recent ASTM D1557 test method. Compacted soil is not
acceptable if it is unstable. It should exhibit only minimal flexing or pumping, as determined by
an ENGEO representative.
As used in this report, the term “moisture condition” refers to adjusting the moisture content of
the soil by either drying if too wet or adding water if too dry.
5.1
GENERAL AREA CLEARING
Clear structural areas, of surface and subsurface deleterious materials including existing building
foundations, slabs, buried utility and irrigation lines, pavements, debris, and designated trees,
shrubs, and associated roots. Clean and backfill excavations extending below the planned
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finished site grades with suitable material compacted to the recommendations presented in
Section 5.5. Retain ENGEO to observe and test all backfilling.
Following clearing, strip structural areas to remove surface organic materials. Strip organics from
the ground surface to a depth of at least 1 to 2 inches below the surface. Remove strippings from
the site or, if considered suitable by the landscape architect and owner, use them in landscape fill.
It may also be feasible to mulch organics in place, depending on the amount and type of
vegetation present at the time of grading as well as the proposed mulching method. If desired,
ENGEO can evaluate site vegetation at the time of grading to determine the feasibility of
mulching organics in place.
5.2
BUILDING AND EQUIPMENT PAD OVEREXCAVATION
In order to avoid expansive clay and mitigate possibly disturbed surface soil, we recommend
overexcavation of building and equipment pads. These areas should be overexcavated a minimum
of 18 inches. The excavation should be backfilled in accordance with Section 5.3 and 5.5.
5.3
ACCEPTABLE FILL
On-site soil material is suitable as fill material provided it is processed to remove concentrations
of organic material, debris, and particles greater than 8 inches in maximum dimension.
Fill within 18 inches of finished grade in building and equipment pad areas should be non
expansive with a plasticity index less than 12, as determined by an ENGEO field representative.
Imported fill materials should meet the above requirements and have a plasticity index less than
12. Allow ENGEO to sample and test proposed imported fill materials at least 72 hours prior to
delivery to the site.
5.4
OVER-OPTIMUM SOIL MOISTURE CONDITIONS
The contractor should anticipate encountering excessively over-optimum (wet) soil moisture
conditions during winter or spring grading, or during or following periods of rain. Wet soil can
make proper compaction difficult or impossible. Wet soil conditions can be mitigated by:
1.
2.
3.
4.
Frequent spreading and mixing during warm dry weather;
Mixing with drier materials;
Mixing with a lime, lime-flyash, or cement product; or
Stabilizing with aggregate, geotextile stabilization fabric, or both.
Options 3 and 4 should be evaluated and approved by ENGEO prior to implementation.
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5.5
FILL COMPACTION
5.5.1
Grading in Structural Areas
8924.000.000
March 26, 2010
Perform subgrade compaction prior to fill placement, following cutting operations, and in areas
left at grade as follows.
1. Scarify to a depth of at least 8 inches;
2. Moisture condition soil to at least 1 percentage point above the optimum moisture content;
and
3. Compact the subgrade to at least 90 percent relative compaction. Compact the upper 6-inches
of finish pavement subgrade to at least 95 percent relative compaction prior to aggregate base
placement.
After the subgrade soil has been compacted, place and compact acceptable fill (defined in
Section 5) as follows:
1. Spread fill in loose lifts that do not exceed 8 inches;
2. Moisture condition lifts to at least 1 percentage point above the optimum moisture content;
and
3. Compact fill to a minimum of 90 percent relative compaction; Compact the upper 6 inches of
fill in pavement areas to 95 percent relative compaction prior to aggregate base placement.
5.5.2
Underground Utility Backfill in Structural Areas
The contractor is responsible for conducting all trenching and shoring in accordance with
CALOSHA requirements. Project consultants involved in utility design should specify pipe
bedding materials.
Place and compact trench backfill as follows:
1. Trench backfill should have a maximum particle size of 6 inches;
2. Moisture condition trench backfill to at least 1 percentage point above the optimum moisture
content. Moisture condition backfill outside the trench;
3. Place fill in loose lifts not exceeding 12 inches; and
4. Compact fill to a minimum of 90 percent relative compaction (ASTM D1557).
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Jetting of backfill is not an acceptable means of compaction. We may allow thicker loose lift
thicknesses based on acceptable density test results, where increased effort is applied to rocky
fill, or for the first lift of fill over pipe bedding.
5.5.3
Underground Utility Backfill in Non-Structural Areas
Process, place and compact fill in accordance with Section 5.5.2, except compact to at least
85 percent relative compaction (ASTM D1557).
5.6
SLOPES GRADIENTS
Construct final slope gradients to 2:1 (horizontal:vertical) or flatter. The contractor is responsible
to construct temporary construction slopes in accordance with CALOSHA requirements.
6.0
FOUNDATION RECOMMENDATIONS
We developed foundation recommendations using data obtained from our field exploration,
laboratory test results, and engineering analysis. As previously mentioned, the alternatives
proposed for solar array panes are use of a single driven steel pipe, H-pile, or precast concrete.
Support for buildings and equipment include conventional footings with slabs-on-grade.
6.1
PILE FOUNDATIONS
The proposed solar arrays can be supported on piles (steel pipe, H beam, or precast concrete)
driven into competent native materials. Pile depth and size should be determined based on the
design criteria presented below. As a minimum, we recommend pile foundations for the solar
arrays extend at lest 6 feet below lowest surrounding grade.
6.1.1
Lateral Pile Capacity
We developed soil profile criteria for use in design of pile foundations based on our boring logs
and laboratory testing. These parameters are intended for use with the computer program
LPILE5. Due to the large size of the site and the three generally distinct geologic units, we have
placed lateral pile design criteria into three general categories corresponding to the least
favorable conditions in each mapped geologic units shown on Figure 3. We tabulate
recommended design parameters for these profiles in Tables 3 through 5 below.
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Table 3
LPILE Parameters – Panoche Alluvial Fans
(Clayey Soil Profile)
Depth
(feet)
Unit
weight
(pci)
Cohesion
(psi)
K static
(pci)
E50
Silty Clay (CL) (modeled as
soft clay - Matlock)
0-2
0.063
2
50
0.02
Silty Clay (CL) (modeled as stiff
clay w/o free water- Reese)
2-15
0.063
14
750
0.006
Layer
Table 4
LPILE Parameters – Franciscan Alluvial Fans
(Sandy Soil Profile)
Layer
Depth
(feet)
Unit
weight
(pci)
Friction
angle
(degrees)
K static
(pci)
Medium Dense Silty/Clayey Sand
(SM/SC) (modeled as Reese Sand)
0-5
0.067
30
90
Dense Silty/Clayey Sand (SM/SC)
(modeled as Reese Sand)
5-15
0.069
34
225
Table 5
LPILE Parameters – Fluvial Deposits
(Loose Sand Profile)
Depth
(feet)
Unit
weight
(pci)
Friction
angle
(degrees)
Loose Sand (SM)
(modeled as Reese Sand)
0-13
0.061
28
--
20
--
Silty Clay (CL) (modeled as stiff
clay w/o free water- Reese)
13-20
0.063
--
14
750
0.006
Layer
Cohesion K static
(psi)
(pci)
E50
Depending on how the ground surface is prepared prior to driving piles, there is a potential for
disturbance and loss of contact in the upper 1 foot of the pile. In addition, some areas of the site
may be capped by a surficial expansive clay layer that can experience some desiccation during
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seasonal dry periods. We recommend that you consider some loss of support in the upper 1 foot
of the driven pile and include this in the overall structural design of the foundation system.
6.1.2
Vertical Pile Capacity
Piles should be designed to resist anticipated vertical dead and live loads. We developed vertical
pile capacity criteria using both skin friction and end bearing for downward resistance and skin
friction only for uplift resistance. We suggest the following average values be used in design for
driven piles.
For downward capacity, we recommend an average end bearing value of 3,000 psf and an
average skin friction value of 400 psf. For resistance to uplift forces, we recommend an average
skin friction value of 200 psf.
Increase the above criteria by one-third for the short-term effects of wind or seismic. The upper
1 foot of the pile should be neglected in design when determining vertical capacity to account for
surface disturbance or soil desiccation.
6.2
CONVENTIONAL FOOTINGS WITH SLAB-ON-GRADE
The proposed equipment structures and support buildings can be supported on continuous or
isolated spread footings bearing in competent native soil or compacted fill. As described in
Section 5.2 and 5.3, building and equipment pad areas should be underlain by at least 18 inches
of non-expansive fill.
6.2.1
Footing Dimensions and Allowable Bearing Capacity
We provide minimum footing dimensions for lightly loaded structures as follows in the Table 6
below.
Table 6
Minimum Footing Dimensions
*Minimum
Footing Type
Depth (in.)
Minimum Width (in.)
Continuous
12
12
Isolated
18
24
*below lowest adjacent pad grade
Minimum footing depths shown above are taken from lowest adjacent pad grade. The cold joint
between the exterior footing and slab-on-grade should be located at least 4 inches above adjacent
exterior grade.
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Design foundations recommended above for a maximum allowable bearing pressure of
2,500 pounds per square foot (psf) for dead plus live loads. Increase this bearing capacity by onethird for the short-term effects of wind or seismic loading
The maximum allowable bearing pressure is a net value; the weight of the footing may be
neglected for design purposes. All footings located adjacent to utility trenches should have their
bearing surfaces below an imaginary 1:1 (horizontal:vertical) plane projected upward from the
bottom edge of the trench to the footing.
6.2.2
Reinforcement
The structural engineer should design footing reinforcement to support the intended structural
loads without excessive settlement. Reinforce all continuous footings with top and bottom steel
to provide structural continuity and to permit spanning of local irregularities. At a minimum,
design continuous footings to structurally span a clear distance of 5 feet.
6.2.3
Foundation Lateral Resistance
Lateral loads may be resisted by friction along the base and by passive pressure along the sides of
foundations. The passive pressure is based on an equivalent fluid pressure in pounds per cubic
foot (pcf). We recommend the following allowable values for design:
Passive Lateral Pressure: 300 pcf
Coefficient of Friction: 0.30
The above allowable values include a factor of safety of 1.5. Increase the above values by onethird for the short-term effects of wind or seismic loading.
Passive lateral pressure should not be used for footings on or above slopes.
6.2.4
Settlement
Provided our report recommendations are followed, and given the proposed construction
(Section 1.3), we estimate total and differential foundation settlements will be less than
approximately ¾ and ½-inch, respectively.
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7.0
SLABS-ON-GRADE
7.1
INTERIOR CONCRETE FLOOR SLABS
7.1.1
Minimum Design Section
We recommend the following minimum design:
1. Provide a minimum concrete thickness of 5 inches.
2. Place minimum steel reinforcing of No. 3 rebar on 18-inch centers each way within the
middle third of the slab to help control the width of shrinkage cracking that inherently occurs
as concrete cures.
The structural engineer should provide final design thickness and additional reinforcement, as
necessary, for the intended structural loads.
7.1.2
Slab Moisture Vapor Reduction
When buildings are constructed with concrete slab-on-grade, water vapor from beneath the slab
will migrate through the slab and into the building. This water vapor can be reduced but not
stopped. Vapor transmission can negatively affect floor coverings and lead to increased moisture
within a building. When water vapor migrating through the slab would be undesirable, we
recommend the following to reduce, but not stop, water vapor transmission upward through the
slab-on-grade.
1. Construct a moisture retarder system directly beneath the slab on-grade that consists of the
following:
a) Vapor retarder membrane sealed at all seams and pipe penetrations and connected to all
footings. Vapor retarders shall conform to Class A vapor retarder per ASTM E 1745-97
“Standard Specification for Plastic Water Vapor Retarders used in Contact with Soil or
Granular Fill under Concrete Slabs”. The vapor retarder should be underlain by
b) 4 inches of clean crushed rock. Crushed rock should have 100 percent passing the ¾-inch
sieve and less than 5 percent passing the No. 4 Sieve.
2. Use a concrete water-cement ratio for slabs-on-grade of no more than 0.50.
3. Provide inspection and testing during concrete placement to check that the proper concrete
and water cement ratio are used.
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4. Moist cure slabs for a minimum of 3 days or use other equivalent curing specified by the
structural engineer.
The structural engineer should be consulted as to the use of a layer of clean sand or pea gravel
(less than 5 percent passing the U.S. Standard No. 200 Sieve) placed on top of the vapor retarder
membrane to assist in concrete curing.
7.1.3
Subgrade Modulus for Structural Slab Design – Equipment Pads
Provided the site earthwork is conducted in accordance with the recommendations of this report,
a subgrade modulus of 150 psi/in can be used for structural slab design. The project structural
engineer should design thickness and reinforcement of structural slabs to accommodate the
proposed loads. We recommend a minimum concrete compressive strength of 3,000 psi.
7.2
TRENCH BACKFILL
Backfill and compact all trenches below slabs-on-grade and to 5 feet laterally beyond any edge in
accordance with Section 5.5.2.
8.0
PAVEMENT DESIGN
8.1
FLEXIBLE PAVEMENTS
We obtained bulk samples of the surface soil from the site and performed R-value tests to
provide data for pavement design. The results of the test are included in Appendix B and indicate
R-values of 10 and 7. Because surface soils vary across the site, and due to expansion pressure
variability, we judged an R-value of 5 to be applicable for design. Using estimated traffic indices
for various pavement loading requirements, we developed the following recommended pavement
sections using Procedure 608 of the Caltrans Highway Design Manual (including the asphalt
factor of safety), presented in Table 7 and 8 below.
Table 7
Recommended Asphalt Concrete Pavement Sections
Section
Traffic Index
Asphalt Concrete (in.)
Class 2 Aggregate Base (in.)
5
2½
11
6
3
14
7
4
16
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Table 8
Recommended Asphalt Concrete Pavement Sections, with 12 inches of Lime Treated Subgrade*
Section
Traffic Index
Asphalt Concrete
Class 2 Aggregate
Lime Treated
(in.)
Base (in.)
Subgrade (in.)
5
2½
4
12
6
3
4
12
7
4
4
12
* See Section 8.4 for lime treatment recommendations
The project civil engineer should determine the appropriate traffic indices based on the estimated
equivalent single axle load frequency at specific areas on site.
8.2
AGGREGATE ROADS
Aggregate base maintenance roads subject to occasional use by lightly loaded vehicles should
consist of a minimum of 20 inches of Class 2 AB placed directly on prepared subgrade. If the
structural section includes 12 inches of lime treated subgrade as outlined in Section 8.3, the AB
section may be reduced to 10 inches. These recommendations are consistent with a TI of 6.
8.3
SUBGRADE AND AGGREGATE BASE COMPACTION
Compact finish subgrade in accordance with Section 5.4. Aggregate Base should meet the
requirements for ¾ -inch maximum Class 2 AB per section 26-1.02a of the latest Caltrans
Standard Specifications. Compact the Class 2 AB section to at least 95 percent relative
compaction (ASTM D1557). Moisture condition aggregate base to or slightly above the optimum
moisture content prior to compaction.
8.4
CHEMICALLY TREATED SUBGRADE
Chemical treatment of fine grained soils may be utilized to improve pavement subgrade
performance. If selected, we recommend uniformly mixing the subgrade soil with 4 percent high
calcium lime by dry weight. The soil should be moisture conditioned to at least 3 percentage
points above the optimum moisture content before mixing. The mixing should be performed in
accordance with the current version of Caltrans Standard Specifications with the following
exceptions:
1. Following mixing, the treated soils should be allowed to fully hydrate prior to compaction.
2. Following hydration, the treated soil should be compacted according to ASTM D-1557 to not
less than 95 percent relative compaction at a moisture content at least 2 percentage points
above the optimum to a non-yielding surface.
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LIMITATIONS AND UNIFORMITY OF CONDITIONS
This report presents geotechnical recommendations for design of the improvements discussed in
Section 1.3 for the Panoche Valley Solar Farm project. If changes occur in the nature or design of
the project, we should be allowed to review this report and provide additional recommendations,
if any. It is the responsibility of the owner to transmit the information and recommendations of
this report to the appropriate organizations or people involved in design of the project, including
but not limited to developers, owners, buyers, architects, engineers, and designers. The
conclusions and recommendations contained in this report are solely professional opinions and
are valid for a period of no more than 2 years from the date of report issuance.
We strived to perform our professional services in accordance with generally accepted
geotechnical engineering principles and practices currently employed in the area; no warranty is
expressed or implied. There are risks of earth movement and property damages inherent in
building on or with earth materials. We are unable to eliminate all risks or provide insurance;
therefore, we are unable to guarantee or warrant the results of our services.
This report is based upon field and other conditions discovered at the time of report preparation.
We developed this report with limited subsurface exploration data. We assumed that our
subsurface exploration data is representative of the actual subsurface conditions across the site.
Considering possible underground variability of soil, rock, stockpiled material, and groundwater,
additional costs may be required to complete the project. We recommend that the owner establish
a contingency fund to cover such costs. If unexpected conditions are encountered, notify ENGEO
immediately to review these conditions and provide additional and/or modified
recommendations, as necessary.
Our services did not include excavation sloping or shoring, soil volume change factors, flood
potential, or a geohazard exploration. In addition, our geotechnical exploration did not include
work to determine the existence of possible hazardous materials. If any hazardous materials are
encountered during construction, then notify the proper regulatory officials immediately.
This document must not be subject to unauthorized reuse that is, reusing without written
authorization of ENGEO. Such authorization is essential because it requires ENGEO to evaluate
the document’s applicability given new circumstances, not the least of which is passage of time.
Actual field or other conditions will necessitate clarifications, adjustments, modifications or
other changes to ENGEO’s documents. Therefore, ENGEO must be engaged to prepare the
necessary clarifications, adjustments, modifications or other changes before construction
activities commence or further activity proceeds. If ENGEO’s scope of services does not include
on-site construction observation, or if other persons or entities are retained to provide such
services, ENGEO cannot be held responsible for any or all claims arising from or resulting from
the performance of such services by other persons or entities, and from any or all claims arising
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from or resulting from clarifications, adjustments, modifications, discrepancies or other changes
necessary to reflect changed field or other conditions.
We determined the lines designating the interface between layers on the exploration logs using
visual observations. The transition between the materials may be abrupt or gradual. The
exploration logs contain information concerning samples recovered, indications of the presence
of various materials such as clay, sand, silt, rock, existing fill, etc., and observations of
groundwater encountered. The field logs also contain our interpretation of the subsurface
conditions between sample locations. Therefore, the logs contain both factual and interpretative
information. Our recommendations are based on the contents of the final logs, which represent
our interpretation of the field logs.
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FIGURES
Figure 1:
Figure 2:
Figure 3:
Figure 4:
Figure 5:
Figure 6:
Vicinity Map
Regional Faulting and Seismicity
Site Plan
Franciscan Alluvial Fan Borings
Panoche Alluvial Fan Borings
Fluvial Deposit Borings
F
I
G
U
R
E
S
N
SA
S
RA
VE
LA
CA
RIO
EGO
GR
K
EE
CR
E
I LL
NV
EE
GR
ER
LV
SI
S AN
SE
JO
N
SA
RR
Santa Clara
AL
OC
TA
LI
GA
TI
OR
BE
ES
EL
RG
VE
EN
UI
BE
SA
Y
RE
Y
BA
SA
S
ITO
RC
LA
TU
RIO
EGO
GR
-
N
TO
R
IZ
EL
N
SA
S
EA
DR
AN
RI
A
AD
ON
NC
N
SA
S
EA
DR
AN
RI
O
NC
DA
NA
NIC
EA
OC
San Benito
NI
BE
S
S
EA
RE
DR
VA
AN
LA
N
CA
SA
Fresno
RE
L IZ
TA
LI
GA
TI
OR
Q
E
NT
MO
SAN
RA
DO
LO
CO
PA
LO
AS
AN
DR
E
SA
N
Santa Cruz
Madera
Merced
S
EA
DR
AN
SA
RG
EN
T
AN
TE
ZAY
SH
AN
NO
N
ST
A
VI
ON
TE
M
Mariposa
Stanislaus
UI
N
JO
AQ
SA
N
Monterey
Kings
B-14
B-4
ER-3
B-3
B-15
B-10
ER-1
B-5
B-2
ER-5
ELECTRICAL RESISTIVITY SURVEY
B-13
B-1
B-16
B-10
ER-1
B-6
B-11A
B-11
B-12
B-21
B-9
ER-4
B-22
B-8
B-20
B-17
B-7
ER-2
B-18
B-19
B-3
B-3
B-2
B-1
B-12
B-13
B-2
B-13
B-1
B-12
B-15
B-4
B-14
B-5
B-16
B-4
B-15
B-5
B-16
B-6
B-17
B-7
B-18
B-6
B-17
B-7
B-18
B-22
B-9
B-11
B-11A
B-10
B-11
B-21
B-9
B-22
B-8
B-20
B-19
B-10
B-21
B-8
B-20
B-19
APPENDIX A
Key to Boring Logs
Exploration Logs
A
P
P
E
N
D
I
X
A
KEY TO SOIL LOGS
COARSE-GRAINED SOILS MORE THAN
HALF OF MAT'L LARGER THAN #200
SIEVE
MAJOR TYPES
GRAVELS
MORE THAN HALF
COARSE FRACTION
IS LARGER THAN
NO. 4 SIEVE SIZE
DESCRIPTION
GW - Well graded gravels or gravel-sand mixtures
CLEAN GRAVELS WITH
LESS THAN 5% FINES
GP - Poorly graded gravels or gravel-sand mixtures
GM - Silty gravels, gravel-sand and silt mixtures
GRAVELS WITH OVER
12 % FINES
SANDS
MORE THAN HALF
COARSE FRACTION
IS SMALLER THAN
NO. 4 SIEVE SIZE
GC - Clayey gravels, gravel-sand and clay mixtures
SW - Well graded sands, or gravelly sand mixtures
CLEAN SANDS WITH
LESS THAN 5% FINES
SP - Poorly graded sands or gravelly sand mixtures
SM - Silty sand, sand-silt mixtures
FINE-GRAINED SOILS MORE
THAN HALF OF MAT'L SMALLER
THAN #200 SIEVE
SANDS WITH OVER
12 % FINES
SC - Clayey sand, sand-clay mixtures
ML - Inorganic silt with low to medium plasticity
SILTS AND CLAYS LIQUID LIMIT 50 % OR LESS
CL - Inorganic clay with low to medium plasticity
OL - Low plasticity organic silts and clays
MH - Elastic silt with high plasticity
SILTS AND CLAYS LIQUID LIMIT GREATER THAN 50 %
CH - Fat clay with high plasticity
OH - Highly plastic organic silts and clays
PT - Peat and other highly organic soils
HIGHLY ORGANIC SOILS
For fine-grained soils with 15 to 29% retained on the #200 sieve, the words "with sand" or "with gravel" (whichever is predominant) are added to the group name.
For fine-grained soil with >30% retained on the #200 sieve, the words "sandy" or "gravelly" (whichever is predominant) are added to the group name.
GRAIN SIZES
U.S. STANDARD SERIES SIEVE SIZE
200
SILTS
AND
CLAYS
10
40
CLEAR SQUARE SIEVE OPENINGS
4
3/4 "
SAND
FINE
3"
MEDIUM
COARSE
FINE
COARSE
VERY LOOSE
LOOSE
MEDIUM DENSE
DENSE
VERY DENSE
COBBLES
BOULDERS
CONSISTENCY
RELATIVE DENSITY
SANDS AND GRAVELS
12"
GRAVEL
SILTS AND CLAYS
BLOWS/FOOT
(S.P.T.)
0-4
4-10
10-30
30-50
OVER 50
VERY SOFT
SOFT
MEDIUM STIFF
STIFF
VERY STIFF
HARD
STRENGTH*
0-1/4
1/4-1/2
1/2-1
1-2
2-4
OVER 4
MOISTURE CONDITION
SAMPLER SYMBOLS
Modified California (3" O.D.) sampler
DRY
MOIST
WET
Dusty, dry to touch
Damp but no visible water
Visible freewater
California (2.5" O.D.) sampler
LINE TYPES
S.P.T. - Split spoon sampler
Solid - Layer Break
Shelby Tube
______
Dashed - Gradational or approximate layer break
Continuous Core
Bag Samples
Grab Samples
NR No Recovery
GROUND-WATER SYMBOLS
Groundwater level during drilling
Stabilized groundwater level
(S.P.T.) Number of blows of 140 lb. hammer falling 30" to drive a 2-inch O.D. (1-3/8 inch I.D.) sampler
* Unconfined compressive strength in tons/sq. ft., asterisk on log means determined by pocket penetrometer
LOG OF BORING B-1
Geotechnical Exploration
Panoche Valle Solar Farm
San Benito County, California
8924.000.000
DATE DRILLED: 3/8/2010
HOLE DEPTH: Approx. 16 ft.
HOLE DIAMETER: 4.0 in.
SURF ELEV (msl):
LOGGED / REVIEWED BY:
DRILLING CONTRACTOR:
DRILLING METHOD:
HAMMER TYPE:
P. Cottingham / MMG
West Coast Exploration
Solid Flight Auger
140 lb. Rope and Cathead
CLAYEY SAND (SC), dark reddish brown, medium dense,
moist, fine- to coarse-grained sand, trace gravel, 30% fines,
weather rock fragment in sampler shoe
Soil corrosion: pH 5.97; minimum resistivity 4.82 ohm-cm
(x1000); chloride 7.0 ppm; sulfate 0.3 ppm.
1
Very dense, with rust staining
12.1
23
76/8"
23
5
2
10
Grades to tan, slightly moist
65/3"
Clay coating on gravel
54/6"
3
LOG - GEOTECHNICAL 8924.000.000 EXPLORATION DATABASE.GPJ ENGEO INC.GDT 3/26/10
4
15
91/11"
Boring terminated at approximately 16 feet. No groundwater
encountered.
6.8
Unconfined Strength
(tsf) *field approx
Dry Unit Weight
(pcf)
Moisture Content
(% dry weight)
Fines Content
(% passing #200 sieve)
Plasticity Index
Plastic Limit
Liquid Limit
Blow Count/Foot
Water Level
DESCRIPTION
Log Symbol
Sample Type
Depth in Meters
Depth in Feet
Atterberg Limits
LOG OF BORING B-2
Geotechnical Exploration
Panoche Valle Solar Farm
San Benito County, California
8924.000.000
DATE DRILLED: 3/8/2010
HOLE DEPTH: Approx. 16 ft.
HOLE DIAMETER: 4.0 in.
SURF ELEV (msl):
LOGGED / REVIEWED BY:
DRILLING CONTRACTOR:
DRILLING METHOD:
HAMMER TYPE:
P. Cottingham / MMG
West Coast Exploration
Solid Flight Auger
140 lb. Rope and Cathead
1
Clay coating on gravel
8.5
120.7
76
5.9
84/9"
3.2
5
2
10
Grades to tan, slightly moist
3
75/10"
LOG - GEOTECHNICAL 8924.000.000 EXPLORATION DATABASE.GPJ ENGEO INC.GDT 3/26/10
4
15
Increasing gravel; mottled with reddish-brown, moist matrix
Boring terminated at approximately 16 feet. No groundwater
encountered.
77/12"
Unconfined Strength
(tsf) *field approx
Dry Unit Weight
(pcf)
Fines Content
(% passing #200 sieve)
Plasticity Index
Plastic Limit
Liquid Limit
Blow Count/Foot
13
Moisture Content
(% dry weight)
CLAYEY SAND (SC), reddish brown, medium dense, moist,
medium- to coarse-grained sand, trace gravel, maximum gravel
size 1.25 inches
Water Level
DESCRIPTION
Log Symbol
Sample Type
Depth in Meters
Depth in Feet
Atterberg Limits
LOG OF BORING B-3
Geotechnical Exploration
Panoche Valle Solar Farm
San Benito County, California
8924.000.000
DATE DRILLED: 3/8/2010
HOLE DEPTH: Approx. 21 ft.
HOLE DIAMETER: 4.0 in.
SURF ELEV (msl):
LOGGED / REVIEWED BY:
DRILLING CONTRACTOR:
DRILLING METHOD:
HAMMER TYPE:
P. Cottingham / MMG
West Coast Exploration
Solid Flight Auger
140 lb. Rope and Cathead
SANDY CLAY (CL), dark brown, stiff, moist, low plasticity, trace
gravel, 40% medium- to coarse-grained sand
Resistance value: 7
5
10.3
Grades to brown, stiff
1
CLAYEY SAND (SC), light reddish brown, dense, damp
Soil corrosion: pH 7.46; minimum resistivity 5.63 ohm-cm
(x1000); chloride 8.0 ppm; sulfate 5.0 ppm.
26
Grades to very dense
67
5
2
10
3
63
LOG - GEOTECHNICAL 8924.000.000 EXPLORATION DATABASE.GPJ ENGEO INC.GDT 3/26/10
4
15
Increasing gravel
83
5
20
6
73/12"
Boring terminated at approximately 21 feet. No groundwater
encountered.
4.5
Unconfined Strength
(tsf) *field approx
Dry Unit Weight
(pcf)
Moisture Content
(% dry weight)
Fines Content
(% passing #200 sieve)
Plasticity Index
Plastic Limit
Liquid Limit
Blow Count/Foot
Water Level
DESCRIPTION
Log Symbol
Sample Type
Depth in Meters
Depth in Feet
Atterberg Limits
1.5*
2.25*
LOG OF BORING B-4
Geotechnical Exploration
Panoche Valle Solar Farm
San Benito County, California
8924.000.000
DATE DRILLED: 3/8/2010
HOLE DEPTH: Approx. 16½ ft.
HOLE DIAMETER: 4.0 in.
SURF ELEV (msl):
LOGGED / REVIEWED BY:
DRILLING CONTRACTOR:
DRILLING METHOD:
HAMMER TYPE:
P. Cottingham / MMG
West Coast Exploration
Solid Flight Auger
140 lb. Rope and Cathead
Dry Unit Weight
(pcf)
13.9
107.3
Unconfined Strength
(tsf) *field approx
Moisture Content
(% dry weight)
Fines Content
(% passing #200 sieve)
Plasticity Index
Plastic Limit
Liquid Limit
Blow Count/Foot
Water Level
DESCRIPTION
Log Symbol
Sample Type
Depth in Meters
Depth in Feet
Atterberg Limits
SILTY SAND (SM), brown, loose, moist, fine- to coarse-grained
sand, trace gravel, with rust staining
5
SANDY SILT (ML), brown, hard, moist, 45% fine-grained sand
1
Grades to damp, light brown
4.5*
7
5
2
10
3
Trace vessicles, (old roots), weak cementation, carbonate
20
SILTY CLAY WITH SAND (CL), light brown, hard, damp, low
plasticity, 40% fine-grained sand, carbonate
40
LOG - GEOTECHNICAL 8924.000.000 EXPLORATION DATABASE.GPJ ENGEO INC.GDT 3/26/10
4
4.5*
29
19
10
7.3
4.5+*
Hard drilling
15
Increasing sand
5
Boring terminated at approximately 16.5 feet. No groundwater
encountered.
29
4.5+*
LOG OF BORING B-5
Geotechnical Exploration
Panoche Valle Solar Farm
San Benito County, California
8924.000.000
DATE DRILLED: 3/8/2010
HOLE DEPTH: Approx. 21½ ft.
HOLE DIAMETER: 4.0 in.
SURF ELEV (msl):
LOGGED / REVIEWED BY:
DRILLING CONTRACTOR:
DRILLING METHOD:
HAMMER TYPE:
P. Cottingham / MMG
West Coast Exploration
Solid Flight Auger
140 lb. Rope and Cathead
1
12.6
Unconfined Strength
(tsf) *field approx
17
Dry Unit Weight
(pcf)
18
Moisture Content
(% dry weight)
Plasticity Index
35
Fines Content
(% passing #200 sieve)
Plastic Limit
Blow Count/Foot
8
Liquid Limit
SILTY CLAY (CL), olive brown, stiff, moist, low to medium
plasticity, with fine-grained sand
Expansion Index: 59.1 (medium expansion potential)
Grades to decreasing moisture
Water Level
DESCRIPTION
Log Symbol
Sample Type
Depth in Meters
Depth in Feet
Atterberg Limits
3.0*
Carbonate and rust staining, trace medium-grained sand
Soil corrosion: pH 7.67; minimum resistivity 0.67 ohm-cm
(x1000); chloride 59.2 ppm; sulfate 675.8 ppm.
23
4.5+*
5
2
10
27
11.7
96.4
4.5+*
3
30
13.1
4.5+*
LOG - GEOTECHNICAL 8924.000.000 EXPLORATION DATABASE.GPJ ENGEO INC.GDT 3/26/10
4
15
Increasing carbonate
75
4.5+*
5
20
6
74
Boring terminated at approximately 21.5feet. No groundwater
encountered.
4.5+*
LOG OF BORING B-6
Geotechnical Exploration
Panoche Valle Solar Farm
San Benito County, California
8924.000.000
DATE DRILLED: 3/8/2010
HOLE DEPTH: Approx. 21 ft.
HOLE DIAMETER: 4.0 in.
SURF ELEV (msl):
LOGGED / REVIEWED BY:
DRILLING CONTRACTOR:
DRILLING METHOD:
HAMMER TYPE:
P. Cottingham / MMG
West Coast Exploration
Solid Flight Auger
140 lb. Rope and Cathead
Unconfined Strength
(tsf) *field approx
Dry Unit Weight
(pcf)
Moisture Content
(% dry weight)
Fines Content
(% passing #200 sieve)
Plasticity Index
Plastic Limit
Liquid Limit
Blow Count/Foot
Water Level
DESCRIPTION
Log Symbol
Sample Type
Depth in Meters
Depth in Feet
Atterberg Limits
SILTY CLAY (CL), dark olive brown, stiff, moist, low plasticity,
trace fine-grained sand
55
2.0*
4.5+*
Grades to hard, weakly cemented, white angular clasts
1
With carbonate
79/12"
13.2
104.8
4.5+*
5
2
10
41
4.5+*
3
76/12"
4.5+*
LOG - GEOTECHNICAL 8924.000.000 EXPLORATION DATABASE.GPJ ENGEO INC.GDT 3/26/10
4
Gravel lense at 12 1/2 feet
15
84/11"
5
20
6
68/12"
Boring terminated at approximately 21 feet. No groundwater
encountered.
4.5+*
LOG OF BORING B-7
Geotechnical Exploration
Panoche Valle Solar Farm
San Benito County, California
8924.000.000
DATE DRILLED: 3/8/2010
HOLE DEPTH: Approx. 26 ft.
HOLE DIAMETER: 4.0 in.
SURF ELEV (msl):
LOGGED / REVIEWED BY:
DRILLING CONTRACTOR:
DRILLING METHOD:
HAMMER TYPE:
P. Cottingham / MMG
West Coast Exploration
Solid Flight Auger
140 lb. Rope and Cathead
14
18.9
19.1
Unconfined Strength
(tsf) *field approx
18
Dry Unit Weight
(pcf)
Plasticity Index
4
Moisture Content
(% dry weight)
Plastic Limit
32
SILTY CLAY (CL), dark olive brown, stiff, moist, low to medium
plasticity, with 10% fine-grained sand
Fines Content
(% passing #200 sieve)
Liquid Limit
Blow Count/Foot
Water Level
DESCRIPTION
Log Symbol
Sample Type
Depth in Meters
Depth in Feet
Atterberg Limits
92.7
1.25*
1
Grades to light brown, abundant small vessicles (old roots)
13
10.9
82.3
4.5*
5
2
10
3
SANDY CLAY (CL), light brown, hard, moist, 40% fine-grained
sand
22
4.5+*
SILTY CLAY (CL), yellowish brown, hard, moist, low plasticity,
trace carbonates, with fine-grained sand
21
9.7
4.5+*
LOG - GEOTECHNICAL 8924.000.000 EXPLORATION DATABASE.GPJ ENGEO INC.GDT 3/26/10
4
15
Grades to medium plasticity, weakly cemented
25
4.5+*
5
Gravel at 18 feet
20
6
Grades to with sand and gravel
41
9.5
81.2
4.5+*
7
25
Grades to with no gravel, carbonate
Boring terminated at approximately 26 feet. No groundwater
encountered.
82/9"
4.5+*
LOG OF BORING B-8
Geotechnical Exploration
Panoche Valle Solar Farm
San Benito County, California
8924.000.000
DATE DRILLED: 3/8/2010
HOLE DEPTH: Approx. 15½ ft.
HOLE DIAMETER: 4.0 in.
SURF ELEV (msl):
LOGGED / REVIEWED BY:
DRILLING CONTRACTOR:
DRILLING METHOD:
HAMMER TYPE:
P. Cottingham / MMG
West Coast Exploration
Solid Flight Auger
140 lb. Rope and Cathead
SANDY CLAY (CL), dark olive brown, very stiff, moist, 40%
fine-grained sand
SILTY SAND (SM), brown, medium dense, moist, fine- to
medium-grained sand
Grades to damp, weakly cemented
16
Grades to clayey
8
Unconfined Strength
(tsf) *field approx
Dry Unit Weight
(pcf)
Moisture Content
(% dry weight)
Fines Content
(% passing #200 sieve)
Plasticity Index
Plastic Limit
Liquid Limit
Blow Count/Foot
Water Level
DESCRIPTION
Log Symbol
Sample Type
Depth in Meters
Depth in Feet
Atterberg Limits
3.5*
47
1
5
SILTY CLAY (CL), brown, very stiff, moist, medium plasticity,
with fine-grained sand
2
10
22
3.75*
3
Grades to cemented, carbonates
Soil corrosion: pH 7.98; minimum resistivity 1.13 ohm-cm
(x1000); chloride 118.4 ppm; sulfate 762.3 ppm.
4
LOG - GEOTECHNICAL 8924.000.000 EXPLORATION DATABASE.GPJ ENGEO INC.GDT 3/26/10
9.7
77
SILTY SAND (SM), light brown, very dense, moist, medium- to
coarse-grained sand, with rust-staining
15
50/5"
Boring terminated at approximately 15.5 feet. No groundwater
encountered.
4.5+*
LOG OF BORING B-9
Geotechnical Exploration
Panoche Valle Solar Farm
San Benito County, California
8924.000.000
DATE DRILLED: 3/8/2010
HOLE DEPTH: Approx. 51 ft.
HOLE DIAMETER: 4.0 in.
SURF ELEV (msl):
LOGGED / REVIEWED BY:
DRILLING CONTRACTOR:
DRILLING METHOD:
HAMMER TYPE:
P. Cottingham / MMG
West Coast Exploration
Solid Flight Auger
140 lb. Rope and Cathead
Dry Unit Weight
(pcf)
13
94.1
Unconfined Strength
(tsf) *field approx
Moisture Content
(% dry weight)
Fines Content
(% passing #200 sieve)
Plasticity Index
Plastic Limit
Liquid Limit
Blow Count/Foot
Water Level
DESCRIPTION
Log Symbol
Sample Type
Depth in Meters
Depth in Feet
Atterberg Limits
SANDY SILT (ML), dark brown, stiff, moist, 45% fine- to
medium-grained sand
7
2.5*
1
22
51
5
2
Grades to with coarse-grained sand and subangular gravel
74/12"
4.9
SILTY GRAVEL (GM), gray and brown, dense, damp
10
3
Weathered sandstone fragments
50/1"
LOG - GEOTECHNICAL 8924.000.000 EXPLORATION DATABASE.GPJ ENGEO INC.GDT 3/26/10
4
15
Subangular gravel (from cuttings), maximum 1 inch
5
20
SILTY CLAY (CL), olive brown, hard, moist, low plasticity, 10%
fine-grained sand
6
25
7
25
8
POORLY GRADED GRAVEL WITH SILT (GP-GM), gray,
dense, moist, subangular to subrounded gravel, maximum size
1 inch
30/1"
23.5
4.25*
LOG OF BORING B-9
Geotechnical Exploration
Panoche Valle Solar Farm
San Benito County, California
8924.000.000
DATE DRILLED: 3/8/2010
HOLE DEPTH: Approx. 51 ft.
HOLE DIAMETER: 4.0 in.
SURF ELEV (msl):
LOGGED / REVIEWED BY:
DRILLING CONTRACTOR:
DRILLING METHOD:
HAMMER TYPE:
P. Cottingham / MMG
West Coast Exploration
Solid Flight Auger
140 lb. Rope and Cathead
POORLY GRADED GRAVEL WITH SILT (GP-GM), gray,
dense, moist, subangular to subrounded gravel, maximum size
1 inch
9
30
10
35
11
SILTY SAND (SM), brown, very dense, damp, medium- to
coarse-grained sand, with gravel, weak cementation, with rust
staining
12
LOG - GEOTECHNICAL 8924.000.000 EXPLORATION DATABASE.GPJ ENGEO INC.GDT 3/26/10
40
81/12"
8.3
84/12"
12.1
13
45
14
15
50
Grades to tan, fine- to medium-grained sand
Boring terminated at approximately 51 feet. No groundwater
encountered.
Unconfined Strength
(tsf) *field approx
Dry Unit Weight
(pcf)
Moisture Content
(% dry weight)
Fines Content
(% passing #200 sieve)
Plasticity Index
Plastic Limit
Liquid Limit
Blow Count/Foot
Water Level
DESCRIPTION
Log Symbol
Sample Type
Depth in Meters
Depth in Feet
Atterberg Limits
LOG OF BORING B-10
Geotechnical Exploration
Panoche Valle Solar Farm
San Benito County, California
8924.000.000
DATE DRILLED: 3/8/2010
HOLE DEPTH: Approx. 51½ ft.
HOLE DIAMETER: 4.0 in.
SURF ELEV (msl):
LOGGED / REVIEWED BY:
DRILLING CONTRACTOR:
DRILLING METHOD:
HAMMER TYPE:
P. Cottingham / MMG
West Coast Exploration
Solid Flight Auger
140 lb. Rope and Cathead
1
5
2
SANDY CLAY (CL), olive brown, stiff, moist, low to medium
plasticity, 20% fines
Expansion Index: 48.5 (low expansion potential); Resistance
value: 10
SILTY CLAY (CL), light olive brown, hard, moist, low plasticity,
trace fine-grained sand
Increasing silt, trace rust staining, grades to tough, medium
plasticity, less silt, olive-brown
Soil corrosion: pH 7.97; minimum resistivity 0.99 ohm-cm
(x1000); chloride 32.7 ppm; sulfate 134.6 ppm.
Unconfined Strength
(tsf) *field approx
Dry Unit Weight
(pcf)
Moisture Content
(% dry weight)
9
2.5*
4.5+*
12.6
18
75
4.5+*
SILTY SAND (SM), olive brown, very dense, moist, fine- to
medium-grained sand, with gravel
85/9"
49
Grades to coarse-grained sand
10
Fines Content
(% passing #200 sieve)
Plasticity Index
Plastic Limit
Liquid Limit
Blow Count/Foot
Water Level
DESCRIPTION
Log Symbol
Sample Type
Depth in Meters
Depth in Feet
Atterberg Limits
3
Medium dense, fine- to medium grained sand, with gravel
23
24
LOG - GEOTECHNICAL 8924.000.000 EXPLORATION DATABASE.GPJ ENGEO INC.GDT 3/26/10
4
SILTY CLAY WITH SAND (CL), brown, hard, moist, low
plasticity, 20% fine-grained sand
15
62
26
16
10
4.5+*
12.3
5
Notably softer at 17 feet
20
6
Increasing silt and fine-grained sand, low plasticity
23
7
25
8
POORLY GRADED SAND WITH SILT (SP-SM), grayish brown,
dense, moist, fine- to coarse-grained sand, trace gravel, well
rounded sand
38
15.3
103.7
4.0*
LOG OF BORING B-10
Geotechnical Exploration
Panoche Valle Solar Farm
San Benito County, California
8924.000.000
DATE DRILLED: 3/8/2010
HOLE DEPTH: Approx. 51½ ft.
HOLE DIAMETER: 4.0 in.
SURF ELEV (msl):
LOGGED / REVIEWED BY:
DRILLING CONTRACTOR:
DRILLING METHOD:
HAMMER TYPE:
P. Cottingham / MMG
West Coast Exploration
Solid Flight Auger
140 lb. Rope and Cathead
Unconfined Strength
(tsf) *field approx
Dry Unit Weight
(pcf)
Moisture Content
(% dry weight)
Fines Content
(% passing #200 sieve)
Plasticity Index
Plastic Limit
Liquid Limit
Blow Count/Foot
Water Level
DESCRIPTION
Log Symbol
Sample Type
Depth in Meters
Depth in Feet
Atterberg Limits
SILTY SAND (SM), brown, medium dense, moist, fine- to
medium-grained sand, 20% silt
9
30
POORLY GRADED SAND WITH GRAVEL (SP), gray, dense,
moist, coarse-grained sand, 5% silt
47
Grades to medium dense, some rust staining
24
10
35
11
4.5+*
SANDY CLAY (CL), olive brown, hard, moist, fine-grained
sand, with rust staining
12
LOG - GEOTECHNICAL 8924.000.000 EXPLORATION DATABASE.GPJ ENGEO INC.GDT 3/26/10
40
Grades to with coarse-grained sand
SILTY CLAY (CL), olive brown, medium stiff, moist, with rust
staining, 10% fine-grained sand
1.75*
4.0*
20
13
SILTY SAND (SM), brown, medium dense, moist, fine- to
coarse-grained sand, with gravel, 15% silt
45
14
23
5.4
40
14.4
Grades to fine-grained sand, 40% silt, trace clay
SANDY CLAY (CL), reddish brown, medium stiff, wet, fine- to
medium-grained sand, trace gravel
15
50
Boring terminated at approximately 51.5 feet. No groundwater
encountered.
0.75*
LOG OF BORING B-11
Geotechnical Exploration
Panoche Valle Solar Farm
San Benito County, California
8924.000.000
DATE DRILLED: 3/15/2010
HOLE DEPTH: Approx. 26½ ft.
HOLE DIAMETER: 4.0 in.
SURF ELEV (msl):
LOGGED / REVIEWED BY:
DRILLING CONTRACTOR:
DRILLING METHOD:
HAMMER TYPE:
P. Cottingham / MMG
West Coast Exploration
Solid Flight Auger
140 lb. Rope and Cathead
Dry Unit Weight
(pcf)
6.8
90.2
Unconfined Strength
(tsf) *field approx
Moisture Content
(% dry weight)
Fines Content
(% passing #200 sieve)
Plasticity Index
Plastic Limit
Liquid Limit
Blow Count/Foot
Water Level
DESCRIPTION
Log Symbol
Sample Type
Depth in Meters
Depth in Feet
Atterberg Limits
CLAYEY SAND (SC), brown, loose, moist, fine- to
medium-grained sand, 35% fines
Soil corrosion: pH 7.76; minimum resistivity 2.28 ohm-cm
(x1000); chloride 17.3 ppm; sulfate 19.7 ppm.
1
5
SANDY SILT (ML), light brown, medium stiff, damp, fine- to
medium-grained sand, trace vessicles
10
49
SILTY SAND (SM), light brown, loose, damp, fine- to
medium-grained sand, 30% fines
2
10
8
7
9.1
3
7
LOG - GEOTECHNICAL 8924.000.000 EXPLORATION DATABASE.GPJ ENGEO INC.GDT 3/26/10
4
SANDY CLAY (CL), brown, hard, moist, low plasticity, trace
carbonates, 40% fine- to medium-grained sand
15
18
5
20
6
59
7
Gravel lense
25
31
8
Boring terminated at approximately 26.5 feet. No groundwater
encountered.
10.8
4.5*
LOG OF BORING B-11A
Geotechnical Exploration
Panoche Valle Solar Farm
San Benito County, California
8924.000.000
DATE DRILLED: 3/15/2010
HOLE DEPTH: Approx. 11½ ft.
HOLE DIAMETER: 4.0 in.
SURF ELEV (msl):
LOGGED / REVIEWED BY:
DRILLING CONTRACTOR:
DRILLING METHOD:
HAMMER TYPE:
P. Cottingham / MMG
West Coast Exploration
Solid Flight Auger
140 lb. Rope and Cathead
SILTY SAND (ML), light brown, medium stiff, damp, fine- to
medium-grained sand, 25% silt
1
8
49
17
72
5
2
Gravel lense
10
3
SANDY CLAY (CL), brown, very stiff, moist, low plasticity
LOG - GEOTECHNICAL 8924.000.000 EXPLORATION DATABASE.GPJ ENGEO INC.GDT 3/26/10
Boring terminated at approximately 11.5 feet. No groundwater
encountered.
Unconfined Strength
(tsf) *field approx
Dry Unit Weight
(pcf)
Moisture Content
(% dry weight)
Fines Content
(% passing #200 sieve)
Plasticity Index
Plastic Limit
Liquid Limit
Blow Count/Foot
Water Level
DESCRIPTION
Log Symbol
Sample Type
Depth in Meters
Depth in Feet
Atterberg Limits
LOG OF BORING B-12
Geotechnical Exploration
Panoche Valle Solar Farm
San Benito County, California
8924.000.000
DATE DRILLED: 3/15/2010
HOLE DEPTH: Approx. 25½ ft.
HOLE DIAMETER: 4.0 in.
SURF ELEV (msl):
LOGGED / REVIEWED BY:
DRILLING CONTRACTOR:
DRILLING METHOD:
HAMMER TYPE:
P. Cottingham / MMG
West Coast Exploration
Solid Flight Auger
140 lb. Rope and Cathead
1
5
2
73/11"
With rust staining
3
87
LOG - GEOTECHNICAL 8924.000.000 EXPLORATION DATABASE.GPJ ENGEO INC.GDT 3/26/10
4
15
Increasing clay, moist
32
Completely weathered, 1.5-inch diameter siltstone fragments,
subrounded 2.5-inch diameter gravel
40
5
20
13.5
6
7
25
67
Boring terminated at approximately 25.5 feet. No groundwater
encountered.
4.4
Unconfined Strength
(tsf) *field approx
Dry Unit Weight
(pcf)
14
Moisture Content
(% dry weight)
14
Fines Content
(% passing #200 sieve)
Plasticity Index
28
CLAYEY SAND WITH GRAVEL (SC), yellowish red, very
dense, damp, 35% fines
63
10
Plastic Limit
Blow Count/Foot
9
Liquid Limit
SILTY CLAY WITH SAND (CL), reddish brown, very stiff, moist,
low to medium plasticity, trace gravel, 15% medium- to
coarse-grained sand
Water Level
DESCRIPTION
Log Symbol
Sample Type
Depth in Meters
Depth in Feet
Atterberg Limits
2.25*
LOG OF BORING B-13
Geotechnical Exploration
Panoche Valle Solar Farm
San Benito County, California
8924.000.000
DATE DRILLED: 3/15/2010
HOLE DEPTH: Approx. 26 ft.
HOLE DIAMETER: 4.0 in.
SURF ELEV (msl):
LOGGED / REVIEWED BY:
DRILLING CONTRACTOR:
DRILLING METHOD:
HAMMER TYPE:
P. Cottingham / MMG
West Coast Exploration
Solid Flight Auger
140 lb. Rope and Cathead
SILTY SAND (SM), brown, loose, moist, medium- to
coarse-grained sand, with gravel, 25% fines
12
5.3
1
Grades to 15% fines, fine- to coarse-grained sand
13
3.5
CLAYEY SAND (SC), light brown, medium dense, damp,
fine-grained sand, 40% fines
5
2
POORLY GRADED SAND WITH GRAVEL (SP), light brown,
dense, damp, medium- to coarse-grained sand
66
SILTY SAND WITH GRAVEL (SM), light olive, dense, damp,
fine- to coarse-grained sand
10
3
44
LOG - GEOTECHNICAL 8924.000.000 EXPLORATION DATABASE.GPJ ENGEO INC.GDT 3/26/10
4
15
Grades to fine-grained sand, dark reddish-brown, trace gravel
32
5
CLAYEY SAND (SC), light brown, very dense, damp, fine- to
coarse-grained sand, with gravel
20
6
72
7
25
76/12"
Boring terminated at approximately 26 feet. No groundwater
encountered.
17
Unconfined Strength
(tsf) *field approx
Dry Unit Weight
(pcf)
Moisture Content
(% dry weight)
Fines Content
(% passing #200 sieve)
Plasticity Index
Plastic Limit
Liquid Limit
Blow Count/Foot
Water Level
DESCRIPTION
Log Symbol
Sample Type
Depth in Meters
Depth in Feet
Atterberg Limits
LOG OF BORING B-14
Geotechnical Exploration
Panoche Valle Solar Farm
San Benito County, California
8924.000.000
DATE DRILLED: 3/15/2010
HOLE DEPTH: Approx. 26½ ft.
HOLE DIAMETER: 4.0 in.
SURF ELEV (msl):
LOGGED / REVIEWED BY:
DRILLING CONTRACTOR:
DRILLING METHOD:
HAMMER TYPE:
P. Cottingham / MMG
West Coast Exploration
Solid Flight Auger
140 lb. Rope and Cathead
Unconfined Strength
(tsf) *field approx
Dry Unit Weight
(pcf)
Moisture Content
(% dry weight)
Fines Content
(% passing #200 sieve)
Plasticity Index
Plastic Limit
Liquid Limit
Blow Count/Foot
Water Level
DESCRIPTION
Log Symbol
Sample Type
Depth in Meters
Depth in Feet
Atterberg Limits
SILTY CLAY (CL), dark brown, very stiff, moist, medium
plasticity, trace fine-grained sand
28
Grades to hard, with carbonates
1
Grades to dark yellowish-brown, damp, 20% sand and gravel
2
58
3
71
POORLY GRADED SAND WITH SILT AND GRAVEL (SP-SM),
yellowish brown, medium dense, damp, fine- to coarse-grained
sand, 30% gravel, 8% fines
27
SILTY SAND (SM), light reddish brown, medium dense, damp,
fine- to medium-grained sand, 40% silt
LOG - GEOTECHNICAL 8924.000.000 EXPLORATION DATABASE.GPJ ENGEO INC.GDT 3/26/10
4
15
Grades to with coarse-grained sand and gravel
34
Grades to trace coarse-grained sand and gravel, trace
carbonates
48
5
20
3.0*
4.5+*
Soil corrosion: pH 7.65 minimum resistivity 1.13 ohm-cm
(x1000); chloride 176.3 ppm; sulfate 653.7 ppm.
5
10
16.2
6
7
25
8
Grades to with coarse-grained sand and gravel, trace clay, 20%
fines
Boring terminated at approximately 26.5 feet. No groundwater
encountered.
59
7.6
4.5+*
LOG OF BORING B-15
Geotechnical Exploration
Panoche Valle Solar Farm
San Benito County, California
8924.000.000
DATE DRILLED: 3/15/2010
HOLE DEPTH: Approx. 21½ ft.
HOLE DIAMETER: 4.0 in.
SURF ELEV (msl):
LOGGED / REVIEWED BY:
DRILLING CONTRACTOR:
DRILLING METHOD:
HAMMER TYPE:
P. Cottingham / MMG
West Coast Exploration
Solid Flight Auger
140 lb. Rope and Cathead
Unconfined Strength
(tsf) *field approx
Dry Unit Weight
(pcf)
Moisture Content
(% dry weight)
Fines Content
(% passing #200 sieve)
Plasticity Index
Plastic Limit
Liquid Limit
Blow Count/Foot
Water Level
DESCRIPTION
Log Symbol
Sample Type
Depth in Meters
Depth in Feet
Atterberg Limits
SANDY SILT (ML), dark brown, stiff, moist, fine-grained sand,
trace rootlets
5
1.5*
4.0*
Grades to yellowish-brown, no rootlets, very stiff
1
SILTY CLAY (CL), yellowish brown, very soft, moist, low
plasticity, trace carbonates, 10% fine-grained sand, trace
vessicles
14
3.5*
5
2
10
25% fine-grained sand, vessicles continue
15
7.2
97
4.5+*
3
19
8.4
4.5+*
7.8
4.5+*
LOG - GEOTECHNICAL 8924.000.000 EXPLORATION DATABASE.GPJ ENGEO INC.GDT 3/26/10
4
15
45
5
20
6
Increasing carbonates, weak cementation
Boring terminated at approximately 21.5 feet. No groundwater
encountered.
75
4.5*
LOG OF BORING B-16
Geotechnical Exploration
Panoche Valle Solar Farm
San Benito County, California
8924.000.000
DATE DRILLED: 3/15/2010
HOLE DEPTH: Approx. 23 ft.
HOLE DIAMETER: 4.0 in.
SURF ELEV (msl):
LOGGED / REVIEWED BY:
DRILLING CONTRACTOR:
DRILLING METHOD:
HAMMER TYPE:
P. Cottingham / MMG
West Coast Exploration
Solid Flight Auger
140 lb. Rope and Cathead
Unconfined Strength
(tsf) *field approx
Dry Unit Weight
(pcf)
Moisture Content
(% dry weight)
Fines Content
(% passing #200 sieve)
Plasticity Index
Plastic Limit
Liquid Limit
Blow Count/Foot
Water Level
DESCRIPTION
Log Symbol
Sample Type
Depth in Meters
Depth in Feet
Atterberg Limits
SANDY CLAY (CL), dark brown, very stiff, moist, low plasticity,
trace rootlets, 40% fine-grained sand
8
Hard, no rootlets
1
Trace vessicles, 45% fine-grained sand, damp
10
14.6
2.25*
4.5*
8.3
3.75*
4.5+*
5
2
10
12
10
78.7
4.5+*
3
Vessicles continue, increase carbonates, medium plasticity
19
Trace gravel
21
Grades to moist
36
4.5+*
LOG - GEOTECHNICAL 8924.000.000 EXPLORATION DATABASE.GPJ ENGEO INC.GDT 3/26/10
4
15
4.5+*
5
20
6
24
7
Boring terminated at approximately 23 feet. No groundwater
encountered.
4.5*
LOG OF BORING B-17
Geotechnical Exploration
Panoche Valle Solar Farm
San Benito County, California
8924.000.000
DATE DRILLED: 3/15/2010
HOLE DEPTH: Approx. 21½ ft.
HOLE DIAMETER: 4.0 in.
SURF ELEV (msl):
LOGGED / REVIEWED BY:
DRILLING CONTRACTOR:
DRILLING METHOD:
HAMMER TYPE:
P. Cottingham / MMG
West Coast Exploration
Solid Flight Auger
140 lb. Rope and Cathead
1
SILTY CLAY WITH SAND (CL), dark yellowish brown, very stiff,
moist, trace gravel
Grades to damp, light yellowish-brown, trace vessicles and
carbonate
Soil corrosion: pH 7.51; minimum resistivity 1.96 ohm-cm
(x1000); chloride 58.7 ppm; sulfate 8.5 ppm.
Cobble encountered at 2.5 feet maximum dimension
23
22
Grades to with gravel (2-inch maximum diameter)
Unconfined Strength
(tsf) *field approx
Dry Unit Weight
(pcf)
Moisture Content
(% dry weight)
Fines Content
(% passing #200 sieve)
Plasticity Index
Plastic Limit
Liquid Limit
Blow Count/Foot
Water Level
DESCRIPTION
Log Symbol
Sample Type
Depth in Meters
Depth in Feet
Atterberg Limits
3.5*
4.5+*
7.3
3.5*
5
2
10
With carbonates, trace fine-grained sand, no gravel
32
Grades to low plasticity
29
Trace gravel
53
4.5+*
3
7.4
4.5+*
LOG - GEOTECHNICAL 8924.000.000 EXPLORATION DATABASE.GPJ ENGEO INC.GDT 3/26/10
4
15
5
SILTY SAND (SM), yellowish brown, dense, damp, fine- to
medium-grained sand, trace carbonates
20
6
40
Boring terminated at approximately 21.5 feet. No groundwater
encountered.
4.5+*
LOG OF BORING B-18
Geotechnical Exploration
Panoche Valle Solar Farm
San Benito County, California
8924.000.000
DATE DRILLED: 3/15/2010
HOLE DEPTH: Approx. 15½ ft.
HOLE DIAMETER: 4.0 in.
SURF ELEV (msl):
LOGGED / REVIEWED BY:
DRILLING CONTRACTOR:
DRILLING METHOD:
HAMMER TYPE:
P. Cottingham / MMG
West Coast Exploration
Solid Flight Auger
140 lb. Rope and Cathead
Unconfined Strength
(tsf) *field approx
Dry Unit Weight
(pcf)
Moisture Content
(% dry weight)
Fines Content
(% passing #200 sieve)
Plasticity Index
Plastic Limit
Liquid Limit
Blow Count/Foot
Water Level
DESCRIPTION
Log Symbol
Sample Type
Depth in Meters
Depth in Feet
Atterberg Limits
SILTY SAND (SM), brown, loose, moist, fine- to
medium-grained sand, 30% fines
8
SANDY CLAY (CH), brown, hard, moist, low plasticity, 35%
fine- to medium-grained sand
4.5*
1
Grades to medium plasticity, with carbonates, weak
cementation, trace vessicles, yellowish-brown
76/12"
54
22
32
12.6
5
2
10
CLAYEY SAND (SC), yellowish brown, very dense, damp, fineto medium-grained sand, trace carbonates, 30% fines
80/9"
Trace gravel
50/6"
Abundant carbonate, moderate cementation
Boring terminated at approximately 15.5 feet. No groundwater
encountered.
63/6"
3
LOG - GEOTECHNICAL 8924.000.000 EXPLORATION DATABASE.GPJ ENGEO INC.GDT 3/26/10
4
15
7.9
4.5+*
LOG OF BORING B-19
Geotechnical Exploration
Panoche Valle Solar Farm
San Benito County, California
8924.000.000
DATE DRILLED: 3/15/2010
HOLE DEPTH: Approx. 26½ ft.
HOLE DIAMETER: 4.0 in.
SURF ELEV (msl):
LOGGED / REVIEWED BY:
DRILLING CONTRACTOR:
DRILLING METHOD:
HAMMER TYPE:
P. Cottingham / MMG
West Coast Exploration
Solid Flight Auger
140 lb. Rope and Cathead
Unconfined Strength
(tsf) *field approx
Dry Unit Weight
(pcf)
Moisture Content
(% dry weight)
Fines Content
(% passing #200 sieve)
Plasticity Index
Plastic Limit
Liquid Limit
Blow Count/Foot
Water Level
DESCRIPTION
Log Symbol
Sample Type
Depth in Meters
Depth in Feet
Atterberg Limits
SILTY CLAY (CL), dark brown, stiff, moist, low plasticity, trace
fine-grained sand
14
Grades to damp, brown
21.9
2.0*
1
Hard, trace vessicles
24
Grades to medium plasticity
18
Grades to moist
23
Grades to low plasticity
19
Increasing carbonates
13
12.2
84.1
2.25*
4.5+*
5
2
10
4.5+*
3
4.5+*
LOG - GEOTECHNICAL 8924.000.000 EXPLORATION DATABASE.GPJ ENGEO INC.GDT 3/26/10
4
15
4.5+*
5
20
6
7
25
25
8
Boring terminated at approximately 26.5 feet. No groundwater
encountered.
4.5*
LOG OF BORING B-20
Geotechnical Exploration
Panoche Valle Solar Farm
San Benito County, California
8924.000.000
DATE DRILLED: 3/15/2010
HOLE DEPTH: Approx. 51½ ft.
HOLE DIAMETER: 4.0 in.
SURF ELEV (msl):
LOGGED / REVIEWED BY:
DRILLING CONTRACTOR:
DRILLING METHOD:
HAMMER TYPE:
P. Cottingham / MMG
West Coast Exploration
Solid Flight Auger
140 lb. Rope and Cathead
Unconfined Strength
(tsf) *field approx
Dry Unit Weight
(pcf)
Moisture Content
(% dry weight)
Fines Content
(% passing #200 sieve)
Plasticity Index
Plastic Limit
Liquid Limit
Blow Count/Foot
Water Level
DESCRIPTION
Log Symbol
Sample Type
Depth in Meters
Depth in Feet
Atterberg Limits
SILTY SAND (SM), brown, very loose, moist, fine- to
medium-grained sand, 25% fines
3
1
SILTY CLAY WITH SAND (CL), yellowish brown, hard, damp,
trace carbonates, 15% fine- to medium grained sand
Soil corrosion: pH 7.67; minimum resistivity 1.02 ohm-cm
(x1000); chloride 25.3 ppm; sulfate 86.8 ppm.
17
4.5+*
5
2
10
CLAY (CH), yellowish brown, hard, damp, high plasticity, with
carbonates, 5% find-grained sand
79
23
30
14.7
4.5+*
3
15% fine- to medium-grained sand
4
LOG - GEOTECHNICAL 8924.000.000 EXPLORATION DATABASE.GPJ ENGEO INC.GDT 3/26/10
53
15
82/9"
4.5+*
SILTY CLAY WITH SAND (CL), yellowish brown, hard, damp,
low plasticity, 15% fine- to medium grained sand
Weak cementation, abundant carbonates
57/6"
5
20
6
Very stiff, mottled with olive-brown, medium plasticity, moist,
15% fine-grained sand
25
7
SILTY SAND (SM), light brown, dense, damp, fine- to
medium-grained sand, trace gravel, 25% fines
25
38
8
19.2
3.25*
LOG OF BORING B-20
Geotechnical Exploration
Panoche Valle Solar Farm
San Benito County, California
8924.000.000
DATE DRILLED: 3/15/2010
HOLE DEPTH: Approx. 51½ ft.
HOLE DIAMETER: 4.0 in.
SURF ELEV (msl):
LOGGED / REVIEWED BY:
DRILLING CONTRACTOR:
DRILLING METHOD:
HAMMER TYPE:
P. Cottingham / MMG
West Coast Exploration
Solid Flight Auger
140 lb. Rope and Cathead
Unconfined Strength
(tsf) *field approx
Dry Unit Weight
(pcf)
Moisture Content
(% dry weight)
Fines Content
(% passing #200 sieve)
Plasticity Index
Plastic Limit
Liquid Limit
Blow Count/Foot
Water Level
DESCRIPTION
Log Symbol
Sample Type
Depth in Meters
Depth in Feet
Atterberg Limits
SILTY SAND (SM), light brown, dense, damp, fine- to
medium-grained sand, trace gravel, 25% fines
9
30
Grades to with silty clay lenses, olive-brown with rust staining
68
10
35
11
Increasing moisture
12
LOG - GEOTECHNICAL 8924.000.000 EXPLORATION DATABASE.GPJ ENGEO INC.GDT 3/26/10
40
Gravel lense, perched groundwater
Grades to 45% fines
Grades to 12% fines, trace, gravel, very dense
80/12"
13
45
14
SANDY CLAY (CL), olive brown, hard, moist, medium
plasticity, 35% sand, with rust staining
15
50
56
Boring terminated at approximately 51.5 feet. Perched
groundwater encountered at approximately 39 feet.
4.5*
LOG OF BORING B-21
Geotechnical Exploration
Panoche Valle Solar Farm
San Benito County, California
8924.000.000
DATE DRILLED: 3/15/2010
HOLE DEPTH: Approx. 21½ ft.
HOLE DIAMETER: 4.0 in.
SURF ELEV (msl):
LOGGED / REVIEWED BY:
DRILLING CONTRACTOR:
DRILLING METHOD:
HAMMER TYPE:
P. Cottingham / MMG
West Coast Exploration
Solid Flight Auger
140 lb. Rope and Cathead
Unconfined Strength
(tsf) *field approx
Dry Unit Weight
(pcf)
Moisture Content
(% dry weight)
Fines Content
(% passing #200 sieve)
Plasticity Index
Plastic Limit
Liquid Limit
Blow Count/Foot
Water Level
DESCRIPTION
Log Symbol
Sample Type
Depth in Meters
Depth in Feet
Atterberg Limits
SILTY CLAY (CL), dark brown, very stiff, moist, trace
fine-grained sand
13
SILTY SAND (SM), dark brown, loose, moist, fine- to
medium-grained sand
3.75*
1
8
43
5
2
10
SILTY CLAY (CL), yellowish brown, hard, damp, low plasticity,
trace sand
14
Grades to medium plasticity, trace vessicles, trace carbonates
18
4.5+*
3
4.5+*
LOG - GEOTECHNICAL 8924.000.000 EXPLORATION DATABASE.GPJ ENGEO INC.GDT 3/26/10
4
15
Mottled reddish-brown and olive-brown
80/12"
4.5+*
5
20
6
Grades to low plasticity
Boring terminated at approximately 21.5 feet. No groundwater
encountered.
62
4.5+*
LOG OF BORING B-22
Geotechnical Exploration
Panoche Valle Solar Farm
San Benito County, California
8924.000.000
DATE DRILLED: 3/15/2010
HOLE DEPTH: Approx. 16½ ft.
HOLE DIAMETER: 4.0 in.
SURF ELEV (msl):
LOGGED / REVIEWED BY:
DRILLING CONTRACTOR:
DRILLING METHOD:
HAMMER TYPE:
P. Cottingham / MMG
West Coast Exploration
Solid Flight Auger
140 lb. Rope and Cathead
Unconfined Strength
(tsf) *field approx
Dry Unit Weight
(pcf)
Moisture Content
(% dry weight)
Fines Content
(% passing #200 sieve)
Plasticity Index
Plastic Limit
Liquid Limit
Blow Count/Foot
Water Level
DESCRIPTION
Log Symbol
Sample Type
Depth in Meters
Depth in Feet
Atterberg Limits
SANDY SILT (ML), dark brown, stiff, moist, fine- to
medium-grained sand
1
Grades to with 15% fine- to medium-grained sand
14
SILTY CLAY (CL), yellowish brown, hard, moist, medium
plasticity, trace carbonates
13
2.0*
4.5+*
5
2
16
9
92.1
4.5+*
12
10
3
LOG - GEOTECHNICAL 8924.000.000 EXPLORATION DATABASE.GPJ ENGEO INC.GDT 3/26/10
4
15
Grades to very stiff
5
Boring terminated at approximately 16.5 feet. No groundwater
encountered.
16
3.25*
APPENDIX B
LABORATORY TEST DATA
Liquid and Plastic Limits Test Report
Unconfined Compression Test
Particle Size Distribution Report
R-Value Test Reports
Analytical Results of Soil Corrosion
Thermal Analysis
A
P
P
E
N
D
I
X
B
#200
#140
#100
#60
#40
#30
#20
#10
#4
3/8 in.
½ in.
¾ in.
1 in.
1½ in.
2 in.
3 in.
6 in.
Particle Size Distribution Report
100
90
80
PERCENT FINER
70
60
50
40
30
20
10
0
100
10
1
0.1
0.01
0.001
GRAIN SIZE - mm.
% Gravel
Coarse
Fine
% +3"
0.0
19.3
Coarse
20.2
13.3
PERCENT
SPEC.*
PASS?
SIZE
FINER
PERCENT
(X=NO)
1-1/2"
1"
3/4"
1/2"
3/8"
#4
#8
#16
#30
#50
#100
#200
100.0
91.0
80.7
74.0
70.3
60.5
49.4
41.8
37.6
33.0
27.4
23.4
SIEVE
% Sand
Medium
11.7
% Fines
Fine
Silt
12.1
Clay
23.4
Soil Description
Clayey Sand
PL=
D85= 21.5585
D30= 0.2091
Cu=
USCS=
Atterberg Limits
LL=
PI=
Coefficients
D60= 4.5934
D50= 2.4582
D15=
D10=
Cc =
Classification
AASHTO=
Remarks
* (no specification provided)
Sample No.: B1@3.0'
Source of Sample: GEX
Location: Panoche Valley Solar Farm
ENGEO, Inc.
Rocklin, CA
Date:
Elev./Depth: 3.0'
Client: Solargen Energy Inc.
Project: Panoche Valley Solar Farm
Project No: 8924.000.000
Figure
#200
#140
#100
#60
#40
#30
#20
#10
#4
3/8 in.
½ in.
¾ in.
1 in.
1½ in.
2 in.
3 in.
6 in.
Particle Size Distribution Report
100
90
80
PERCENT FINER
70
60
50
40
30
20
10
0
100
10
1
0.1
0.01
0.001
GRAIN SIZE - mm.
% Gravel
Coarse
Fine
% +3"
0.0
0.0
Coarse
0.0
0.1
PERCENT
SPEC.*
PASS?
SIZE
FINER
PERCENT
(X=NO)
1-1/2"
1"
3/4"
1/2"
3/8"
#4
#8
#16
#30
#50
#100
#200
100.0
100.0
100.0
100.0
100.0
100.0
99.9
99.8
99.4
94.1
72.3
47.1
SIEVE
% Sand
Medium
1.5
% Fines
Fine
Silt
51.3
Clay
47.1
Soil Description
Silty Sand
PL=
D85= 0.2143
D30=
Cu=
USCS=
Atterberg Limits
LL=
PI=
Coefficients
D60= 0.1072
D50= 0.0812
D15=
D10=
Cc =
Classification
AASHTO=
Remarks
* (no specification provided)
Sample No.: B8@1.5'
Source of Sample: GEX
Location: Panoche Valley Solar Farm
ENGEO, Inc.
Rocklin, CA
Date:
Elev./Depth: 1.5'
Client: Solargen Energy Inc.
Project: Panoche Valley Solar Farm
Project No: 8924.000.000
Figure
#200
#140
#100
#60
#40
#30
#20
#10
#4
3/8 in.
½ in.
¾ in.
1 in.
1½ in.
2 in.
3 in.
6 in.
Particle Size Distribution Report
100
90
80
PERCENT FINER
70
60
50
40
30
20
10
0
100
10
1
0.1
0.01
0.001
GRAIN SIZE - mm.
% Gravel
Coarse
Fine
% +3"
0.0
0.0
Coarse
2.4
1.4
PERCENT
SPEC.*
PASS?
SIZE
FINER
PERCENT
(X=NO)
1-1/2"
1"
3/4"
1/2"
3/8"
#4
#8
#16
#30
#50
#100
#200
100.0
100.0
100.0
100.0
100.0
97.6
96.4
95.7
94.7
89.2
71.8
51.0
SIEVE
% Sand
Medium
3.0
% Fines
Fine
Silt
42.2
Clay
51.0
Soil Description
Silty Sand
PL=
D85= 0.2435
D30=
Cu=
USCS=
Atterberg Limits
LL=
PI=
Coefficients
D60= 0.1010
D50=
D15=
D10=
Cc =
Classification
AASHTO=
Remarks
* (no specification provided)
Sample No.: B9@4.0'
Source of Sample: GEX
Location: Panoche Valley Solar Farm
ENGEO, Inc.
Rocklin, CA
Date:
Elev./Depth: 4.0'
Client: Solargen Energy Inc.
Project: Panoche Valley Solar Farm
Project No: 8924.000.000
Figure
#200
#140
#100
#60
#40
#30
#20
#10
#4
3/8 in.
½ in.
¾ in.
1 in.
1½ in.
2 in.
3 in.
6 in.
Particle Size Distribution Report
100
90
80
PERCENT FINER
70
60
50
40
30
20
10
0
100
10
1
0.1
0.01
0.001
GRAIN SIZE - mm.
% Gravel
Coarse
Fine
% +3"
0.0
0.0
Coarse
11.4
7.2
PERCENT
SPEC.*
PASS?
SIZE
FINER
PERCENT
(X=NO)
1-1/2"
1"
3/4"
1/2"
3/8"
#4
#8
#16
#30
#50
#100
#200
100.0
100.0
100.0
97.3
93.9
88.6
82.8
77.4
72.3
65.9
57.1
48.5
SIEVE
% Sand
Medium
12.0
% Fines
Fine
Silt
20.9
Clay
48.5
Soil Description
Silty Sand w/Gravel
PL=
D85= 3.0586
D30=
Cu=
USCS=
Atterberg Limits
LL=
PI=
Coefficients
D60= 0.1869
D50= 0.0847
D15=
D10=
Cc =
Classification
AASHTO=
Remarks
* (no specification provided)
Sample No.: B10@7.0'
Source of Sample: GEX
Location: Panoche Valley Solar Farm
ENGEO, Inc.
Rocklin, CA
Date:
Elev./Depth: 7.0'
Client: Solargen Energy Inc.
Project: Panoche Valley Solar Farm
Project No: 8924.000.000
Figure
#200
#140
#100
#60
#40
#30
#20
#10
#4
3/8 in.
½ in.
¾ in.
1 in.
1½ in.
2 in.
3 in.
6 in.
Particle Size Distribution Report
100
90
80
PERCENT FINER
70
60
50
40
30
20
10
0
100
10
1
0.1
0.01
0.001
GRAIN SIZE - mm.
% Gravel
Coarse
Fine
% +3"
0.0
0.0
Coarse
10.3
15.2
PERCENT
SPEC.*
PASS?
SIZE
FINER
PERCENT
(X=NO)
1-1/2"
1"
3/4"
1/2"
3/8"
#4
#8
#16
#30
#50
#100
#200
100.0
100.0
100.0
100.0
93.7
89.7
77.8
64.2
49.5
38.4
29.8
22.8
SIEVE
% Sand
Medium
31.1
% Fines
Fine
Silt
20.6
Clay
22.8
Soil Description
Silty Sand w/Gavel
PL=
D85= 3.3678
D30= 0.1527
Cu=
USCS=
Atterberg Limits
LL=
PI=
Coefficients
D60= 0.9708
D50= 0.6144
D15=
D10=
Cc =
Classification
AASHTO=
Remarks
* (no specification provided)
Sample No.: B10@10.0'
Source of Sample: GEX
Location: Panoche Valley Solar Farm
ENGEO, Inc.
Rocklin, CA
Date:
Elev./Depth: 10.0'
Client: Solargen Energy Inc.
Project: Panoche Valley Solar Farm
Project No: 8924.000.000
Figure
#200
#140
#100
#60
#40
#30
#20
#10
#4
3/8 in.
½ in.
¾ in.
1 in.
1½ in.
2 in.
3 in.
6 in.
Particle Size Distribution Report
100
90
80
PERCENT FINER
70
60
50
40
30
20
10
0
100
10
1
0.1
0.01
0.001
GRAIN SIZE - mm.
% Gravel
Coarse
Fine
% +3"
0.0
0.0
Coarse
1.1
0.5
PERCENT
SPEC.*
PASS?
SIZE
FINER
PERCENT
(X=NO)
1-1/2"
1"
3/4"
1/2"
3/8"
#4
#8
#16
#30
#50
#100
#200
100.0
100.0
100.0
100.0
100.0
98.9
98.5
98.0
97.0
93.2
82.3
49.0
SIEVE
% Sand
Medium
2.9
% Fines
Fine
Silt
46.5
Clay
49.0
Soil Description
Silty Sand
PL=
D85= 0.1644
D30=
Cu=
USCS=
Atterberg Limits
LL=
PI=
Coefficients
D60= 0.0914
D50= 0.0763
D15=
D10=
Cc =
Classification
AASHTO=
Remarks
* (no specification provided)
Sample No.: B11@3.5'
Source of Sample: GEX
Location: Panoche Valley Solar Farm
ENGEO, Inc.
Rocklin, CA
Date:
Elev./Depth: 3.5'
Client: Solargen Energy Inc.
Project: Panoche Valley Solar Farm
Project No: 8924.000.000
Figure
#200
#140
#100
#60
#40
#30
#20
#10
#4
3/8 in.
½ in.
¾ in.
1 in.
1½ in.
2 in.
3 in.
6 in.
Particle Size Distribution Report
100
90
80
PERCENT FINER
70
60
50
40
30
20
10
0
100
10
1
0.1
0.01
0.001
GRAIN SIZE - mm.
% Gravel
Coarse
Fine
% +3"
0.0
0.0
Coarse
0.0
0.1
PERCENT
SPEC.*
PASS?
SIZE
FINER
PERCENT
(X=NO)
1-1/2"
1"
3/4"
1/2"
3/8"
#4
#8
#16
#30
#50
#100
#200
100.0
100.0
100.0
100.0
100.0
100.0
99.9
99.8
99.5
97.7
88.0
72.1
SIEVE
% Sand
Medium
0.7
% Fines
Fine
Silt
27.1
Clay
72.1
Soil Description
Sandy Clay
PL=
D85= 0.1297
D30=
Cu=
USCS= SP
Atterberg Limits
LL=
PI=
Coefficients
D60=
D50=
D15=
D10=
Cc =
Classification
AASHTO=
Remarks
* (no specification provided)
Sample No.: B11A@10.0'
Source of Sample: GEX
Location: Panoche Valley Solar Farm
ENGEO, Inc.
Rocklin, CA
Date:
Elev./Depth: 10.0'
Client: Solargen Energy Inc.
Project: Panoche Valley Solar Farm
Project No: 8924.000.000
Figure
#200
#140
#100
#60
#40
#30
#20
#10
#4
3/8 in.
½ in.
¾ in.
1 in.
1½ in.
2 in.
3 in.
6 in.
Particle Size Distribution Report
100
90
80
PERCENT FINER
70
60
50
40
30
20
10
0
100
10
1
0.1
0.01
0.001
GRAIN SIZE - mm.
% Gravel
Coarse
Fine
% +3"
0.0
0.0
Coarse
1.0
0.9
PERCENT
SPEC.*
PASS?
SIZE
FINER
PERCENT
(X=NO)
1-1/2"
1"
3/4"
1/2"
3/8"
#4
#8
#16
#30
#50
#100
#200
100.0
100.0
100.0
100.0
100.0
99.0
98.2
97.5
95.6
87.6
75.2
49.0
SIEVE
% Sand
Medium
5.9
% Fines
Fine
Silt
43.2
Clay
49.0
Soil Description
Silty Sand
PL=
D85= 0.2469
D30=
Cu=
USCS=
Atterberg Limits
LL=
PI=
Coefficients
D60= 0.0973
D50= 0.0768
D15=
D10=
Cc =
Classification
AASHTO=
Remarks
* (no specification provided)
Sample No.: B11A@3.0'
Source of Sample: GEX
Location: Panoche Valley Solar Farm
ENGEO, Inc.
Rocklin, CA
Date:
Elev./Depth: 3.0'
Client: Solargen Energy Inc.
Project: Panoche Valley Solar Farm
Project No: 8924.000.000
Figure
#200
#140
#100
#60
#40
#30
#20
#10
#4
3/8 in.
½ in.
¾ in.
1 in.
1½ in.
2 in.
3 in.
6 in.
Particle Size Distribution Report
100
90
80
PERCENT FINER
70
60
50
40
30
20
10
0
100
10
1
0.1
0.01
0.001
GRAIN SIZE - mm.
% Gravel
Coarse
Fine
% +3"
0.0
11.7
Coarse
20.8
13.5
PERCENT
SPEC.*
PASS?
SIZE
FINER
PERCENT
(X=NO)
1-1/2"
1"
3/4"
1/2"
3/8"
#4
#8
#16
#30
#50
#100
#200
100.0
90.8
88.3
85.4
78.0
67.5
56.6
45.9
36.6
27.6
20.7
16.8
SIEVE
% Sand
Medium
22.0
% Fines
Fine
Silt
15.2
Clay
16.8
Soil Description
Silty Sand w/Gravel
PL=
D85= 12.4611
D30= 0.3627
Cu=
USCS=
Atterberg Limits
LL=
PI=
Coefficients
D60= 2.8892
D50= 1.5555
D15=
D10=
Cc =
Classification
AASHTO=
Remarks
* (no specification provided)
Sample No.: B13@10.0'
Source of Sample: GEX
Location: Panoche Valley Solar Farm
ENGEO, Inc.
Rocklin, CA
Date:
Elev./Depth: 10.0'
Client: Solargen Energy Inc.
Project: Panoche Valley Solar Farm
Project No: 8924.000.000
Figure
#200
#140
#100
#60
#40
#30
#20
#10
#4
3/8 in.
½ in.
¾ in.
1 in.
1½ in.
2 in.
3 in.
6 in.
Particle Size Distribution Report
100
90
80
PERCENT FINER
70
60
50
40
30
20
10
0
100
10
1
0.1
0.01
0.001
GRAIN SIZE - mm.
% Gravel
Coarse
Fine
% +3"
0.0
0.0
Coarse
0.5
0.6
PERCENT
SPEC.*
PASS?
SIZE
FINER
PERCENT
(X=NO)
1-1/2"
1"
3/4"
1/2"
3/8"
#4
#8
#16
#30
#50
#100
#200
100.0
100.0
100.0
100.0
100.0
99.5
99.0
98.7
98.3
90.8
65.1
43.1
SIEVE
% Sand
Medium
2.3
% Fines
Fine
Silt
53.5
Clay
43.1
Soil Description
Silty Sand
PL=
D85= 0.2487
D30=
Cu=
USCS=
Atterberg Limits
LL=
PI=
Coefficients
D60= 0.1302
D50= 0.0950
D15=
D10=
Cc =
Classification
AASHTO=
Remarks
* (no specification provided)
Sample No.: B21@3.0'
Source of Sample: GEX
Location: Panoche Valley Solar Farm
ENGEO, Inc.
Rocklin, CA
Date:
Elev./Depth: 3.0'
Client: Solargen Energy Inc.
Project: Panoche Valley Solar Farm
Project No: 8924.000.000
Figure
Unconfined Compression Test
ASTM Test Method D2166
1400
1200
Axial pressure (psf)
1000
800
600
400
200
0
0
2
4
6
8
10
12
Percent Strain
Unconfined Compressive Strength:
1250 psi
0.6 tsf
Sample Description: (ML) Brown Sandy Silt
Initial Diameter:
Initial Height:
Strain Rate:
Total Strain:
EN GEO
INCORPORATED
2.42
4.41
1.15
2.49
in.
in.
%/min
%
Sample Number:
Boring Number:
Dry Unit Weight:
Moisture Content:
Depth of Sample:
Panoche Valley Solar Farm
Panoche Valley, CA
B4-6.5
B4
89.8 pcf
7.4 %
6.5 ft.
Job
No.: 8924.000.000
Sample
B4-6.5
Number:
Date:
3/11/2010
Figure
No.
Unconfined Compression Test
ASTM Test Method D2166
1400
1200
Axial pressure (psf)
1000
800
600
400
200
0
0
2
4
6
8
10
12
Percent Strain
Unconfined Compressive Strength:
1160 psi
0.6 tsf
Sample Description: (ML) Brown Sandy Silt
Initial Diameter:
Initial Height:
Strain Rate:
Total Strain:
EN GEO
INCORPORATED
2.42
5.50
0.72
4.18
in.
in.
%/min
%
Sample Number:
Boring Number:
Dry Unit Weight:
Moisture Content:
Depth of Sample:
Panoche Valley Solar Farm
Panoche Valley, CA
B9-1
B9
98.4
15.2
1.0
pcf
%
ft.
Job
No.: 8924.000.000
Sample
B9-1
Number:
Date:
3/11/2010
Figure
No.
Unconfined Compression Test
ASTM Test Method D2166
2500
Axial pressure (psf)
2000
1500
1000
500
0
0
2
4
6
8
10
12
Percent Strain
Unconfined Compressive Strength:
2200 psi
1.1 tsf
Sample Description: (ML) Dark Brown Sandy Silt
Initial Diameter:
Initial Height:
Strain Rate:
Total Strain:
EN GEO
INCORPORATED
2.42
4.20
1.27
5.71
in.
in.
%/min
%
Sample Number:
Boring Number:
Dry Unit Weight:
Moisture Content:
Depth of Sample:
Panoche Valley Solar Farm
Panoche Valley, CA
B15-1.5
B15
99.7 pcf
14.3 %
1.5 ft.
Job
8924.000.000
No.:
Sample
B15-1.5
Number:
Date:
3/19/2010
Figure
No.
Unconfined Compression Test
ASTM Test Method D2166
2000
1800
1600
Axial pressure (psf)
1400
1200
1000
800
600
400
200
0
0
2
4
6
8
10
12
Percent Strain
Unconfined Compressive Strength:
1750 psi
0.9 tsf
Sample Description: (CL) Dark Brown Sandy Clay
Initial Diameter:
Initial Height:
Strain Rate:
Total Strain:
EN GEO
INCORPORATED
2.42
4.95
2.00
3.64
in.
in.
%/min
%
Sample Number:
Boring Number:
Dry Unit Weight:
Moisture Content:
Depth of Sample:
Panoche Valley Solar Farm
Panoche Valley, CA
B16-4
B16
91.7 pcf
7.3 %
4.0 ft.
Job
8924.000.000
No.:
Sample
B16-4
Number:
Date:
3/19/2010
Figure
No.
LIQUID AND PLASTIC LIMITS TEST REPORT
60
O
H
Dashed line indicates the approximate
upper limit boundary for natural soils
CH
or
50
O
L
30
or
20
CL
PLASTICITY INDEX
40
10
CL-ML
4
7
0
0
10
ML or OL
20
30
40
MH or OH
50
60
LIQUID LIMIT
70
80
90
100
110
SOIL DATA
SYMBOL
NATURAL
WATER
CONTENT
(%)
PLASTIC
LIMIT
(%)
LIQUID
LIMIT
(%)
PLASTICITY
INDEX
(%)
1.5'
10.3
13
25
12
CL
B4@11.0'
11.0'
7.3
19
29
10
CL
GEX
B5@1.5'
1.5'
12.6
18
35
17
CL
GEX
B7@1.5'
1.5'
19.1
18
32
14
CL
GEX
B10@16.0'
16.0'
12.3
16
26
10
CL
SOURCE
SAMPLE
NO.
DEPTH
GEX
B3@1.5'
GEX
ENGEO, Inc.
Client: Solargen Energy Inc.
Project: Panoche Valley Solar Farm
Rocklin, CA
Project No.: 8924.000.000
Figure
USCS
LIQUID AND PLASTIC LIMITS TEST REPORT
60
Dashed line indicates the approximate
upper limit boundary for natural soils
50
PLASTICITY INDEX
CH
OH
or
40
30
L
rO
o
CL
20
10
CL-ML
ML or OL
4
7
MH or OH
0
0
10
20
30
40
50
60
LIQUID LIMIT
70
80
90
100
SOIL DATA
NATURAL
WATER
CONTENT
(%)
PLASTIC
LIMIT
(%)
LIQUID
LIMIT
(%)
SOURCE
SAMPLE
NO.
DEPTH
GEX
B12@1.5'
1.5'
13.5
14
28
14
0.0
CL
GEX
B18@4.0'
4.0'
12.6
22
54
32
-0.3
CH
GEX
B20@7.0'
7.0'
14.7
23
53
30
-0.3
CH
ENGEO, Inc.
Rocklin, CA
PLASTICITY LIQUIDITY
INDEX
INDEX
(%)
Client: Solargen Energy Inc.
Project: Panoche Valley Solar Farm
Project No.: 8924.000.000
Figure
USCS
110
R VALUE TEST REPORT
CAL-301
90
85
80
75
70
65
60
55
45
R-Value
50
40
35
30
25
20
15
10
5
0
900
800
700
600
500
400
300
200
100
0
Exudation Pressure (psi)
Date:
Project Name:
Project Number:
Sample:
Description:
3/19/10
Panoche Valley Solar Farm
8924.000.000
B3 (0-1')
(CL) Brown Sandy Clay w/gravel
Specimen
Exudation Pressure, p.s.i.
Expansion dial (.0001")
Expansion Pressure, p.s.f.
Resistance Value, "R"
% Moisture at Test
Dry Density at Test, p.c.f.
"R" Value at 300 p.s.i., Exudation Pressure
A
743
5
22
38
8.6
140.3
B
311
0
0
8
10.8
134.4
7
C
208
0
0
0
12.1
131.2
R VALUE TEST REPORT
CAL-301
90
85
80
75
70
65
60
55
45
R-Value
50
40
35
30
25
20
15
10
5
0
900
800
700
600
500
400
300
200
100
0
Exudation Pressure (psi)
Date:
Project Name:
Project Number:
Sample:
Description:
3/19/10
Panoche Valley Solar Farm
8924.000.000
B10 (0-1')
(CL) Brown Sandy Clay
Specimen
Exudation Pressure, p.s.i.
Expansion dial (.0001")
Expansion Pressure, p.s.f.
Resistance Value, "R"
% Moisture at Test
Dry Density at Test, p.c.f.
"R" Value at 300 p.s.i., Exudation Pressure
A
795
178
771
48
15.1
117.9
B
677
120
520
33
16.9
111.6
10
C
287
0
0
10
20.6
104.4
GeothermUSA
http://www.geotherm.net
6354 Clark Ave.
Dublin, CA 94568
Tel:
925-999-9232
Fax: 925-999-8837
info@geothermusa.com
March 20, 2010
ENGEO
2213 Plaza Drive
Rocklin, CA 95765
ATTN: Dana Tolar
Re: Thermal Analysis of Native Soil Samples
Panoche Valley Solar Project – Job No. 8924.000.000
The following is the report of thermal dryout characterization tests conducted on the two (2)
native soil samples from the referenced project. These were undisturbed tube samples.
Test Procedure and Equipment:
The tests included the measurement of moisture content, density and thermal dryout
characterization (thermal resistivity as a function of moisture content). A laboratory
type thermal probe was installed central and vertical in each samples and a series of
measurements were made in stages, with moisture contents ranging from the ‘natural’
to the totally dry condition. The tests were conducted in accordance with the IEEE
standard.
The results are tabulated below and the thermal dryout curves are
presented in Figure 1.
Sample ID, Description, Moisture Content, Dry Density and Thermal Resistivity
Thermal
Resistivity
(°C-cm/W)
Wet
Dry
Location
#
Depth
(ft)
Visual Description
B-3
4
Clayey Sand with gravel
79
B-10
6.5
Silty Sand with trace
gravel
88
Moisture
Content
(%)
Dry
Density
(pcf)
147
6
112
189
6
109
COOL SOLUTIONS FOR UNDERGROUND POWER CABLES
THERMAL SURVEYS, CORRECTIVE BACKFILLS & INSTRUMENTATION
Serving the electric power industry since 1978
GeothermUSA
Comments
The thermal characteristic depicted in Figure 1 will apply only if the soils are at dry
densities of not less than the test values.
Please contact us if you have any questions, wish to discuss any part of this report or if
we can be of further assistance.
Geotherm USA
Nimesh Patel
Please Note: All samples will be disposed of after 5 days from date of report
2
GeothermUSA
3
GeothermUSA
http://www.geotherm.net
6354 Clark Ave.
Dublin, CA 94568
Tel:
925-999-9232
Fax: 925-999-8837
info@geothermusa.com
March 24, 2010
ENGEO
2213 Plaza Drive
Rocklin, CA 95765
Attn: Dana Tolar
Re: Thermal Analysis of Native Soil Sample
Panoche Valley Solar Project – Job No. 8924.000.000
The following is the report of thermal dryout characterization tests conducted on the one (1)
native soil sample from the referenced project. This was an undisturbed tube sample.
Test Procedure and Equipment:
The tests included the measurement of moisture content, density and thermal dryout
characterization (thermal resistivity as a function of moisture content). A laboratory
type thermal probe was installed central and vertical in the sample and a series of
measurements were made in stages, with moisture contents ranging from the ‘natural’
to the totally dry condition. The tests were conducted in accordance with the IEEE
standard. The results are tabulated below and the thermal dryout curve is presented
in Figure 1.
Sample ID, Description, Moisture Content, Dry Density and Thermal Resistivity
Location
#
Depth
(ft)
Visual Description
B-15
4
Silty CLAY with trace fine
sand
Thermal
Resistivity
(°C-cm/W)
Wet
Dry
151
288
Moisture
Content
(%)
Dry
Density
(pcf)
7.3
94
COOL SOLUTIONS FOR UNDERGROUND POWER CABLES
THERMAL SURVEYS, CORRECTIVE BACKFILLS & INSTRUMENTATION
Serving the electric power industry since 1978
GeothermUSA
Comments
The thermal characteristic depicted in Figure 1 will apply for the soil at dry density of
not less than the test values.
Please contact us if you have any questions, wish to discuss any part of this report or if
we can be of further assistance.
Geotherm USA
Nimesh Patel
Please Note: All samples will be disposed of after 5 days from date of report
2
GeothermUSA
3
APPENDIX C
NORCAL Geophysical
Electrical Resistivity Test Data
A
P
P
E
N
D
I
X
C