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Geotechnical • Geologic • Environmental
5741 Palmer Way • Carlsbad, California 92008 • (760) 438-3155 • FAX (760) 931-0915
October 11, 2000
W.0. 2929-A-SC
Mr. David Bentley
7 449 Magellan Street
Caflsbad, California 92009
Subject: Limited Geotechoical Evaluation, Holly Springs Project, Carlsbad, San Diego
County, California
Reference: "Holly Springs, 56-R-1 Lots, 1 Multifamily Lot, 3 Opeh Space Lots," sheets 1
and 2, Job L-1061, undated, by Ladwig Design Group. ·
Dear Mr. Bentley:
In accordance with the request of Mr. Bob Ladwig (Ladwig Design Group), and your
authorization, GeoSoils, Inc. (GSI) has performed a limited geotechnical evaluation of the
subject site with regard to the proposed development. The purpose of our investigation
was to evaluate geotechnical conditions of the site and present preliminary
recommendations for grading and foundation design and construction for the proposed
.. development. The client should note that additional geotechnical studies will likely be
warranted as detailed grading plans are available.
EXECUTIVE SUMMARY
Based on our review of the available data (Appendix A), field exploration, laboratory
testing, and limited geologic and engineering analysis, the proposed development appears
to be feasible from a geotechnical viewpoint, provided the recommendations presented
in the text of this report are properly incorporated into-the design and construction of the
project. The most significant elements of this study are summarized below:
•
•
Preliminary laboratory test results indicate that site materials have a negligible
potential for corrosion to concrete (i.e., $Ulfate content) and a severely high
potential for corrosion to exposed ferrous materials (i.e., saturated resistivity).
Our preliminary laboratory test results and field observations indicate that soils with
a very low to possibly high expansion potential underlie the site. Foundation design
and construction recommendationsare provided herein, based on these conditions.
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•
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All alluvial and topsoil/colluvial soils, and the .. upper ± 1 to ±3 feet of weathered
bedrock are generally soft and potentially compressible and/or do not meet the
current industry minimum standard of 90 percent (or greater) relative compaction
and will require removal and recompaction. Based upon our limited subsurface
evaluation, combined removal· depths are estimated to range between ± 1 to ± 7
feet below existing grade in areas proposed for settlement sensitive improvements.
Qverall, the majority of the property is underlain by volcanic/metavolcanic bedrock
of the Santiago Peak Volcanics intruded by a suit of granitic rock belonging to the
southern California batholith. In the southwesterly portion of the property, however,
a sedimentary unit consisting of the Santiago Formation was encountered. Based
upon the anticipated, west-sloping contact between the younger sedimentary
formation with the underlying granitic/Volcanic bedrock, westerly-facing slopes may
require stabilization in the vicinity of the multi-family area (i.e., Lot 1). Further
evaluation is recommended once 40-scale grading plans become available.
In additi_on to backhoe test pits, a limited seismic refraction survey was performed
to assess the rippability ·of bedrock materials. Results of the seismic refraction
survey suggested dense to very dense, non-rippable bedrock materials exist at a
depth, locally, of ±15 to ±30 feet. The rippability of the bedrock within the . .
proposed grading limits is expected to be highly variable. For budgetary purposes,
however, surface rock, hard layers and floaters (isolated hard zones and/or
boulders) will likely be encountered that will be difficult to excavate with
conventional grading equipment, and may require blasting from the surface.
• The bulk of the materials derived from the weathered portion of the dense, hard
.. . bedrock are anticipated to disintegrate to approximately 12-to 24-inch diameters
and smaller. Fills should be well-graded mixtures of fines with rock no larger than
12 inches in diameter. Rocks larger than 12 inches will require special handling for
use in fills. For preliminary planning purposes, it can be assumed at least 50% -of
materials excavated from granitic and/or volcanic areas will generate oversized rock
(i.e., 12 inches or· greater) requiring special handling. However, such an estimate
should be used with caution, and not without consulting a grading contractor
experienced with residential development in hard rock terranes. Further evaluation
is recommended once 40-scale grading plans become available.
• Subsurface. water is not anticipated to affect site development, providing that the
recommendations contained in this report are incorporated into final design and
construction and that prudent surface and subsurface drainage practices are
incorporated into the construction plans. Perched groundwater conditions along
zones of contrasting permeabilities should not be precluded from occurring in the
future due to site irrigation, poor drainage conditions, or damaged utilities. Should
perched groundwater conditions develop, this office could assess the affected
area(s) and provide the appropriate recommendations to mitigate. the observed
groundwater conditions. Subdrains may be recommended during grading.
Mr. David Bentley
File:e:\wp7\2900\2929a.lge
GeoSoils, Inc.
W.O. 2929-A-SC
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• The preliminary geotechnical design parameters provided herein should be
considered during construction by the project structural engineer and/or architect.
The opportunity to be of service is greatly appreciated. If you have any questions
concerning this report or if we may be of further assistance, please do not hesitate to
contact any of the undersigned.
Respectfully submitted,
Mr. David Bentley
File:e:\wp7\2900\2929a.lge
GeoSoils, lne.
W.O. 2929-A-SC
Page Three
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TABLE OF CONTENTS
SCOPE OF SERVICES ................................................... 1
SITE DESCRIPTION AND PROPOSED DEVELOPMENT ...................... ; .. 1
FIELD EXPLORATION .................................................... 3
REGIONAL GEOLOGY ................................................... 3
EARTH MATERIALS ................................ · ...................... 4
Topsoil/Colluvium (Not Mapped) ...................................... 4
Santiago Formation (Map Symbol -Tsa) ................................ 4
· · Granitics/Santiago Peak Volcanics (Map Symbols -Kgr/Jsp) ............... 4
GROUNDWATER ............. , ............................. : ·:.'. .···: ......... 5
FAUL TING AND REGIONAL SEISMICITY ..................................... 5
Se1sm1c1ty ................ · . . . . . . . . . . . • . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Seismic Shaking Parameters ......................................... 8
PRELIMINARY ROCK HARDNESS EVALUATION .. : ........................... 9
Rock Disposal ......................... ~ . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
LABORATORY TESTING .................. ~ .............................. 10
General ....................•.................................... 1 O
Classification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 o
· Laboratqry Standard-Maximum Dry Density ~ . ~ • . . . . . . . . . . . . . . . . . . . . . . . . 1 o
Expansion Potential . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 O
Atterberg Limits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 o
Soluble Sulfates/pH Resistivity .... .-................... ·. . . . . . . . . . . . . . 11
CONCLUSIONS AND RECOMMENDATIONS ................................ 11
General .......................................................... 11
Earth Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Topsoil/Colluvium (No Map Symbol) ............................ 12
Santiago Formation (Map Symbol -Tsa), Granitic Bedrock (Map Symbol -
Kgr), and Volcanic/Metavolcanic Bedrock (Map Symbol-Jsp) ... 12
Preliminary Rock Hardness ....................... .-. . . . . . . . . . . . . . . . . 12
Expansion Potential ...... : . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Subsurface and Surface Water . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Regional Seismic Activity ........... ~ 1 • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • 13
Slope Considerations and Slope Design · . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
EARTHWORK CONSTRUCTION RECOMMENDATIONS ....................... 14
General ............. ~ . ~ ....................... : . . . . . . . . . . . . . . . . . 14
Demolition/Grubbing .............................................. ·14
Treatment of Existing Ground .-. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
GeoSoils, .Irie.
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Fill Placement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Overexcavation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Erosion Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
RECOMMENDATIONS-FOUNDATIONS ..................... · ............. :. 16
Bearing Value ................. · . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Lateral Pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Footing Setbacks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Construction . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Very Low to Low Expansion Potential (Expansion Index O to 50) . . . . . . . . . . . 18
Medium Expansion Potential (Expansion Index 51 to ·90) ................. 19
High Expansion Potential (Expansion Index 91 to 130)/Preliminary Post-Tensioned
Slab Foundation Systems ..................................... 20
CORROSION ....... : ...... ; ......................•.................... 22
CONVENTIONAL RETAINING WALL RECOMMENDATIONS .................... 22
General ............ : . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Restrained Walls . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Cantilevered Walls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Wall Backfill and Drainage ................. .-. . . . . . . . . . . . . . . . . . . . . . . . 24
Retaining Wall Footing Transitions ._ .................................. 24
RECOMMENDATIONS-POST EARTHWORK ................................. 25
Planting and Landscape Maintenance ................................ 25
Additional Site Improvements ....................................... 25
__ Footing Trench Excavation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Drainage .............. _ .......................................... 26
TRENCH BACKFILL ..................................................... 26
PLAN REVIEW . :·: ....................................................... 26
INVESTIGATION LIMITATIONS .............................. · .............. 27
FIGURES:
Figure 1 -Site Location .Map ......................................... 2
Figure 2 -California Fault Map ........................................ 6
ATTACHMENTS:
Appendix A -References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Rear of Text
Appendix 8 -Test Pit Logs .......... '.-: ..... · ................. Rear of Text
Appendix C -Seismic Data .......... ~ . . . . . . . . . . . . . . . . . . . . . . Rear of Text
Appendix D -General Earthwork and Grading Guidelines ......... Rear of Text
Plates 1 and 2 .. Geotechnical Maps ......... -......... Rear of Text in Pocket
Mr. David. Bentley
File: e\wp7\2900\2929a.lge
GeoSoils, lne.
Table of Contents
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LIMITED GEOTECHNICAL EVALUATION
HOLLY SPRINGS PROJECT
CARLSBAD, SAN DIEGO COUNTY, CALIFORNIA
SCOPE OF SERVICES
The scope of our services has included the following:
1. · Review of readily available published literature . and maps of the vicinity
(Appendix A).
2. Limited subsurface exploration consisting of eleven exploratory test pits to evaluate
the existing soil conditions.
3. Limited seismic refraction survey consisting of four seismic lines to evaluate rock.
hardness.
4. Limited laboratory testing of representative soil samples collected during our
subsurface exploration program.
5. General areal site seismicity and slope stability evaluation.
6. Preparation of a preliminary geotechnical report for the subject site that includes
seismic evaluation, and recommendations for anticipated remedial site grading to
mitigate identified geologic hazards. Since detailed development plans (i.e.,
·· building locations, building types, etc.) for the site are not available at this time,
specific foundation design and construction details should be provided as plans
become available.
SITE DESCRIPTION AND PROPOSED DEVELOPMENT
The generally undeveloped property is located in northeastern Carlsbad, north of El
Camino Real and the Rancho Carlsbad/Sintorosa Golf Course, and directly west of the
southwesterly portion of Leisure Village/Ocean Hills in San Diego, County, California (see
Site Location Map, Figure 1). Access to the subject property is via the northern, recently
improved extension of Calaveras Drive (north of Cannon Road and El Camino Real
intersection). Overall, the property is covered with what appears to be native vegetation;
however, portions of the south-central property (and farmland to the south) are currently
developed for agricultural purposes. A few structures are readily visible in a main
·compound area, situated within Open Space Lot 58; however, a number of .cultivated
banana trees currently exist west of the compound, within areas proposed for grading and
development.
The site is bounded on the north and south by agriclJltural development mixed with
predominantly undeveloped open space areas consisting of ridges and westerly-flowing
GeoSoils_, lne.
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Ba.se Map: San Luis Rey Quadrangle, California--San Diego C_o., 7.5 Minute Series (Topographic),'
1968 (revised 1975), by· USGs·, 1 .. :2000'
0 1/2 1
Scale Miles N
Re.produced with permlaalon granted by Tho,naa Bto1. Mapa. Thia map la ·copyrighted by Thomas Bros, Mapa, It 11 unlawful to copy or repro-cluce 111 or any part thereof, wt,ether for.
personal UH or resale, without permission, All ,right• reserved,
;
All Locations Are -Approximate . .
w.o.
2929-A-SC
SITE LOCATION MAP
Figure 1
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intermittent natural drainages. The eastern edge of the property is bounded by Leisure
Village. A vehicle storage area and agricultural plots associated with a trailer park exist
to the west. The south central portion of the property is currently developed for agricultural
purposes, with farm support structures and an irrigation system.
Overall, the site slopes in a westerly direction toward Calaveras Creek; however, the
southern edge of the property slopes in a south to southwest direction. Based upon a 100-
scale topographic map/conceptual developmental plan of Holly Springs (by Ladwig Design
Group, ·tnc.), elevations onsite range from ±420 fe~t Mean Sea Level (MSL) in the eastern
area to roughly ± 70 feet MSL in the western area. At the time of our field reconnaissance
the site in covered predominantly with native grasses and brush. Surface rock outcrops
are locally common within the higher elevations of the property.
The aforementioned plans for the subject property (by Ladwig Design Group, Inc.)
indicates that 1 multi-family lot (Lot 1), 56 single-family Jots (Lots 2-57),with 3 open space
.lots (Lots 58, 59, and 60) and interior roads are planned for the property. Although.
construction plans are not available, it is likeiy that residential structures will use
continuous footings and slab-on-grade floors with wood-frame and/or masonry block
construction. Building loads are assumed to be typical for this type of relatively light
structure. The need for import soil (i.e., fill materials) is not known at this time.
FIELD EXPLORATION
Subsurface conditions were explored for this study by excavating eleven (11) exploratory
backhoe test pits to depths ranging from about ±2 to ± 1 o feet below existing grade. Field
·· work· for the test pits was performed on September 19, 2000 by a GSI geologist, who
logged the trenches, obtained samples of representative materials for laboratory testing
and reviewed the site conditions. Logs of the test pits are presented in Appendix B. The
approximate locations of exploratory test pits are indicated on the Preliminary Geotechnical
Mc1-ps (Plates 1 and 2), which. utilize a 100-scale developmental map as a base map.
In addition, four (4) seismic refraction lines were conducted on the property to assess the
rippability of _the bedrock materials. The seismic lines were completed on September 19,
2000 by a GSI staff geologist and field technician. Graphic sections of the four lines, along
with interpretations, are provided in Appendix C. The approximate locations are indicated
on the 100-scale Geotechnical Maps (Plates 1 and 2).
REGIONAL GEOLOGY
The site is located in Peninsular Ranges geomorphic province of California. The
Peninsular Ranges are characterized by northwest-trending, steep, elongated ranges and
valleys. The Peninsular Ranges extend north to the base of the San Gabriel Mountains and
Mr. David Bentley
Holly Springs, Carlsbad
File: e\wp7\2900\292_9a.lge
. .
GeoSoils, Inc.
W.O. 2929-A-SC
October 11, 2000
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south into Mexico to Baja California. The province is bounded by the east-west trending
Transverse Ranges geomorphic province to the north and northeast, by the Colorado
Desert geomorphic province to the southeast, and by the Continental Borderlands
geomorphic province to the west. In the Peninsular Ranges, sedimentary and volcanic
units discontinuously mantle the crystalline bedrock, alluvial deposits have filled in the
lower valley areas, ·and young marine sediments are currently being deposited/eroded in
the coastal and beach areas.
EARTH MATERIALS
Earth materials encountered on the site consist of topsoil/colluvium, sediments of the
Eocene-age Santiago Formation, granitic bedrock of the southern California Batholith, and
volcanic/metavolcanic bedrock of the Jurassic-age Santiago Peak Volcanics. Mappable
units are shown on the Geotechnical Maps, Plates 1 and 2. the earth units encountered
are described below, from youngest to oldest.
Topsoil/Colluvium (Not Mapped)
Quaternary-age. topsoil/colluvium (i.e., surficial deposits) was observed overlying the site.
Topsoil/colluvium, as encountered onsite, consists of dry, red brown to gray, loose, silty
· sand with occasionally common gravel, that is compressible. These sediments were
encountered typically to a depth of ± 1 to ±3 foot; however, colluvium was encountered
to a depth of 5 to 7 feet overlying the Santiago formation in Lot 1. These materials are
considered unsuitable for support of settlement sensitive improvements in their existing
condition.
Santiago Formation (Map Symbol -Tsa)
Underlying the surficial deposits in the extreme westerly portion of the property is· a
formational unit, consisting of sediments belonging to the Eocene-age Santiago Formation.
These sediments, as encountered onsite, consist of moist, medium dense, yellow-brown
sandstones with interbedded siltstone and claystone beds: These materials are considered
suitable for support of settlement sensitive improvements, provided the upper weathered
portion of the unit is removed and/or reproce~sed.
· Granitics/Santlago Peak Volcanics (Map Symbols -Kgr/Jsp)
Underlying the. property as a whole, as well as exposed locally at the surface in the form
of outcrops, are intrusions of granitic bedrock of the Cretaceous-age southern California
Batholith (Kgr) into volcanic/metavolcanic bedrock of the Jurassic-age Santiago Peak
Volcanics. Where encountered onsite, there materials consisted of brown to gray to red
brown, dense to very dense and hard bedrock that typically excavated to silty sands and
silty sandy gravels. Although this material was found to be decomposed and massive,
Mr. David Bentley
Holly Springs, Carlsbad
File: e\wp7\2900\2929a.lge
. GeoSoils, lne.
W.O. 2929-A-SC
October 11, 2000
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practical refusal was achieved at depths between 3½ and 7 feet. Difficult excavation
operations should be anticipated below a depth of ±5 feet with conventional grading
equipment, or from the surface where rock outcrops exist. The need for blasting to achieve
design grade{s) may not be precluded, and should be anticipated. This bedro_ck is
considered suitable for support of settlement sensitive improvements, provided the upper
weathered portion of this unit is removed and/or reprocessed.
GROUNDWATER
Subsurface water was not encountered in any of the excavations completed during this
study. Subsurface water is not anticipated to adversely affect site development, provided
that the recommendations contained in this report are incorporated into final design and
construction, and that prudent surface and subsurface drainage practices are incorporated
into the construction plans. These observations reflect site conditions at the time of our
investigation and _do not preclude future changes in local groundwater conditions from
exces_sive irrigation, precipitation, or that were not obvious, at the time of our investigation.
Seeps, springs, or other indications of a high groundwater level were not noted on the
subject property during the time of our field investigation. However, seepage may occur
locally {due to heavy precipitation or irrigation) in areas where fill soils overlie silty or clayey
. soils. Such soils may be encountered in the earth ~nits that exist onsite.
Perched groundwater conditions along fill/bedrock contacts and along zones of
contrasting permeabilities should not be precluded from -occurring in the future due to site
irrigation, poor drainage conditions, or damaged utilities. Should perched groundwater
-· conditions develop, this office could assess .the affected area(s) and provide the
appropriate· recommendations to mitigate the observed groundwater conditions.
Subdrains may be recommended during grading based on the conditions exposed.
FAULTING AND REGIONAL SEISMICITY
The site is situated in an area of active as well as potentially-active faults. Our review
indicates that there are no known active faults crossing the site within the areas proposed
for development {Jennings, 1994), and the site is not within an Earthquake Fault Zone
(Hart and Bryant, 1997). · No evidence of faulting was encountered in our subsurface
investigation.
There are a number of faults in the southern California area which are considered active
and. would have an effect on the site in the form of ground shaking, should they be the
source of an earthquake. These include, but are not limited to: the San Andreas fault, the
San Jacinto fault, the Elsinore fault, the Coronado Bank fault zone and the Rose Canyon -
Newport-Inglewood {RCNI) fault zone .. The approximate location of these and other major
Mr. David Bentley
Holly Springs, Carlsbad
File: e\wp7\2900\2929a.lge
GeoSoils, ·Ine.
W.O. 2929-A-SC
October 11, 2000
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SAN FRANCISCO
SITE LOCAIION ( + )': ----·--,----
Latitude -33.1530 N
Longitude -11 7 .2810 W
HOLLY SPRINGS
W .0. 2929-A-SC
CALIFORNIA
0 50 100
SCALE
Figure 2
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faults relative to the site are presented in Figure 2. The possibility of ground acceleration,
or shaking, at the site may be considered as approximately similar to the southern
California region as a whole.
The acceleration-attenuation relations of Idriss (1994), and Campbell and Bozorgnia
(1994) have been incorporated into EQFAULT (Blake, 1997). EQFAULT is a computer
program used for the deterministic evaluation of horizontal accelerations from digitized
California faults.
The following table lists the major faults and fault zones in s.outhern California that could
have a significant effect on the site should they experience significant activity.
1-~:~\~sa·F«Ev1Ar~o r=AuL·f~iAMe.r_..l .. ~P-~Rox,MitE;ois,-ANcE··Mii1i {KM}· I
Coronado Bank-Aaua Blanca 23(37.0)
Elsinore 22(35.4)
La Nacion 23(37.0)
-
Newport-Inglewood-Offshore 11(17.7)
Rose Canyon 7(11.3)
. San Diego Trough-Bahia Sol. 33(53.1)
Seismlcity
The acceleration-attenuation relations of Idriss (1994) and Campbell and Bozorgnia (1994)
have been incorporated into EQFAULT (Blake, 1997). For this study, peak horizontal
ground accelerations anticipated at the site were determined based on the random mean
attenuation curves developed by Idriss (1994) and Campbell and Bozorgnia (1994). These
ac9eleration-attenuation relations have been incorporated in EQFAULT, a co·mputer
program by Thomas F. Blake (1997), which performs deterministic seismic hazard analyses
using up to 150 digitized California faults as earthquake sources.
The program estimates the closest distance between each fault and a user-specified file.
If a fault is found to be within a user-selected radius, the program estimates peak horizontal
ground acceleration that may occur at the site from the 11upper bound" (maximu~ credible)
and 11maximum probable11 earthquakes on that fault. Site acceleration (g) is computed by
any of the 14 user-selected acceleration-attenuation relations that are contained in
EQFAULT. Based on the above, peak horizontal ground accelerations from an upper
bound event may be on the order of 0.451 g to 0.493 g, and a maximum probable event
may be on the order of 0.246 g to 0.262 g, assuming an upper bound (maximum credible)
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Holly Springs, Carlsbad
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and maximum probable event of magnitude about 6.9, on the Rose Canyon fault zone,
located approximately 7 miles west from the subject site.
Seismic Shaking Parameters
Based on the site conditions, Chapter 16 of the Uniform Building Code {International
Conference of Building Officials, 1997) and Peterson and others (1996), the following
seismic parameters are provided.
Seismic zone (per Figure 16-2*) 4
Seismic Zone Factor (per Table 16-1*) 0.40
Soil Profile Type (per Table 16-J*) S6 **, S/**, S0 ****
Seismic Coefficient c. (per Table 16-Q*) 0.40 N.
Seismic Coefficient Cv (perTable 16-R*) 0.56 Nv
Near Source Factor N. (per Table 16-S*) 1.0
Near Source Factor Nv (per Table 16-T*) 1.2
Seismic Source Type (per Table 16-U*) B
Distance to Seismic Source 7 mi. (11.2 km)
Upper Bound Earthquake Mw6.9
* Figure and table references from ,Chapter 16 of the Uniform Building Code (1997).
** S6 may be used for lots underlain by bedrock (Granitics/Santiago Peak Volcanics)
*** Sc may be used for lots by bedrock (Granitics/Santiago Peak Volcanics), where fills are more than
1 O feet below the bottom of the footings.
**** S0 may be used for lots underlain by formational sediments (Santiago Formation), or for lots wher!3
fills have been placed on formational sediments.
It should be noted that the parameters above are provided for the average soil properties
for the top 100 feet of the soil profile. The S8 parameters are reasonably and
conservatively justified for competent rock with moderate fracturing and weathering based
on an estimated shear wave Velocity (a "S" wave) of greater than 2,500 feet per second
{fps) in the top 100 feet of the soil profile, as contrasted to the velocities used in our
seismic refraction studies {a "P" wave). The estimate S wave velocities are about 0.58 of
P wave velocities measured in our seismic refractions studies (Das, 1992; Hunt, 1986; and
Griffiths and King, 1976). Accordingly, in accordance with the 1997 UBC, it is reasonably
estimated that the shear wave velocity for the average soil profile of the top 100 feet of the
soil profile exceeds 2,500 fps in granitic/volcanic bedrock.
Mr. David Bentley
Holly Springs, Carlsbad
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PRELIMINARY ROCK HARDNESS EVALUATl'ON
A limited subsurface investigation, consisting of 4 seismic refraction survey lines was
pe·rformed to assess the rippability of the bedrock materials. The results of the limited
seismic refraction survey are provided in Appendix C. The ·Iocations of the seismic lin·es
are shown on the Preliminary Geotechnical Maps, Plates 1 and 2.
For the purposes of this discussion, approximate cut-off seismic velocities of 6000 feet per
second were used as a basis for non-rippable bedroc~. Approximate cut-off seismic
velocities of 3800 feet per second should be used as a basis for non-rippable tren·ching.
Rippability of bedrock within the proposed grading limits is expected to be highly variable.
Generally, excavations will likely require· blasting below depths of ± 15 to ±30 feet.
Bedrock appears to be rippable with heavy grading equipment at shallower depths;
however, in these "rippable" areas, surface rock outcrops, hard layers, and floaters
(isolated hard zones and/or boulders) will be encountered that will be difficult to excavate
with conventional grading ·equipment, and may require blasting. A more detailed rock
hardness evaluation is recommended as 401-scale grading plans become available.
Rock Disposal
· The bulk of the materials derived from the weathered portion of the bedrock (up to and
including the 3000-4500+ fps cut-off) are anticipated to disintegrate to approximately 12-
to 24-inch diameters and smaller: Fills should be well-graded mixtures of fines with rock
no larger than 12 inches in diameter. Rocks ·Iarger than 12 inches will require special
handling for use in fills. Typically, oversized rocks are placed in rock blankets, rock
· windrows, and/or pits for individual rocks. The major constraints to rock disposal on the
subject site are the limited areas suitable for rock disposal and the availability of fines
required for filling rock fill voids. Oversized rock should be held below the range of
foundations, utilities, or other underground excavations to facilitate trenching, and held-at
least 15± ·feet away from slope faces, so as not to adversely affect slope stability.
For preliminary planning purposes, it can be assumed at least 50% of materials excavated
will generate oversized· rock (i.e., 12 inches or greater) requiring special handling.
However, such an estimate should be used with caution, and not without consulting a
grading contractor experienced with residential development in hard rock terranes.
Mr. David Bentley
Holly Springs, Carlsbad
File: e\wp7\2~00\2929a.lge
GeoSoils, lne.
W.O. 2929-A-SC
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LABORATORY TESTING
General
Laboratory tests were performed on representative samples of the onsite earth materials
in order to evaluate their physical characteristics. Test procedures used and results
obtained are presented below. ·
Classification
Soils were classified visually according to the Unified Soils Classification System. The soil
classifications are shown on the test pit logs iri Appendix B.
Laboratory Standard-Maximum Dry Density
To determine the compaction characteristics of representative samples of onsite soil,
laboratory testing was performed in accordance with ASTM test method D-1557. Test
.results are presented in the following table: ·
TP-2@0-1' 129.0 10.0
Expansion Potential
Expansion index tests were performed on a representative sample of site soil in general
accordance with Standard 18-2 of the Uniform Building Code. Results are presented in the
following table. · -
! <5 ! Very Low I
Atterberg Limits
To help determine the consistency and plasticity of fine grained soils on the site, a selective
sample was chosen and tested for their Atterberg Limits. Testing was completed pursuant
to post-tensioned foundation design requirements presented in the 1997 Uniform Building
Code (UBC). The testing was performed in accordance with ASTM Test Method D-4318.
The results are presented in the following table:
Mr. David Bentley
Holly Springs, Carlsbad
File: e\wp7\2900\2929a.lge
GeoSoils, Ine,
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SAMPLE LOCATION I. . LIQUID LIMIT I PLASTICITY INDEX
TP-2@0-1' I Non Plastic I Non Plastic
Soluble Sulfates/pH Resistivity
A sample of the thicker colluvial materials were analyzed for soluble sulfate content and
corrosion to ferrous metals. The results are as follows:
l·"iocATION">-1 :soLUBLE SULFATES.(mgikg) l,'pH·· r_,-RESISTIVl'rf-SATURATED (oh.ms-cm) 1
I TP-10 @5-7' I 50 I 7.0 I 780 I
CONCLUSIONS AND RECOMMENDATIONS
General
Based on our field exploration, laboratory testing and geotechnical engineering analysis,
-it is our opinion that the site appears suitable for. the proposed development from a
geotechnical engineering and geologic viewpoint, provided that the recommendations
presented in the following sections are incorporated into the design and construction
phases of site development. The primary geotechnical concerns with respect to the
proposed development are:
•
•
Earth materials characteristics and depth to competent bearing material.
Expansion and corrosion potential of site soils .
•
•
•
Potential for drill and shoot/bl~sting .
Regional seismic activity .
Subsurface water and potential for perched water .
The recommendations presented herein consider these as well as other aspects of the site.
In the event that any significant changes are made to proposed site development, the
conclusions and recommendations contained in this report shall not be considered valid
unless the changes are reviewed and the recommendations of this report verified or
modified in writing by this office. Additional subsurface studies, including rock hardness
evaluation, are recommended as more detailed plans are available. Foundation design
parameters are considered preliminary until the foundation design, layout, and structural
loads are provided to this office for review.
Mr. David Bentley
Holly Springs, Carlsbad
File: e\wp7\2900\2~29a.lge
GeoSoils, Jne.
W.O. 2929-A-SC
October 11, 2000
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Earth Materials
Topsoil/Colluvium (No Map Symbol)
Topsoil/colluvial materials are generally moist and loose and/or do not meet the current
industry minimum standard of 90 percent (or greater) relative compaction.
Recommendations for the treatment of topsoil/colluvium are presented in the earthwork
section of this report.
Santiago Formation (Map Symbol -Tsa), Granitic Bedrock (Map Symbol -Kgr), and
Volcanic/Metavolcanic Bedrock (Map Symbol-Jsp)
Formational and bedrock materials will be encountered during site earthwork. These
materials are considered competent to support settlement-sensitive structures in their
existing state, provided the upper highly weathered portions are reprocessed and moisture
conditioned. The Santiago Formation should be excavated with conventional heavy
grading equipment. Difficulty should be anticipated below a depth of ±5 feet where
granitic and/or volcanic/metavolcanic bedrock is encountered. The need for blasting may
not be precluded, and should be locally anticipated.
Preliminary Rock Hardness
The results of the seismic refraction survey suggested dense to very dense, non-rippable
bedrock materials exist at a depth, locally, of ±15 to ±30 feet. The rippability of the
bedrock within the proposed grading limits is expected to be highly variable. For
budgetary purposes, however, surface rock outcrops, hard layers, and floaters (isolated
hard zones and/or boulders) will likely be encountered that will be difficult to excavate with
conventional grading equipment, and may require blasting.
Expansion· Potential
Based upon our experience in the area, as well as upon review of laboratory test results
indicate that soils with a very low to possibly high expansion potential underlie the site.
Field observations of the siltstone and claystone interbeds of the Santiago formation
suggest that they may have a medium to high expansion potential. This should be
-considered during project desig_n. Foundation design and construction recommendations
_ are provided herein for very low to high expansion potential classifications.
Subsurface and Surface Water
Subsurface and surface waters, as discussed previously, are not anticipated to affect site
development, provided that the recommendations contained in this report are incorporated
into final design and construction, and that prudent surface and subsurface drainage
practices are incorporated into the construction plans.
Mr. David Bentley
Holly Springs, Carlsbad
File: e\wp7\2900\2929a.lge
GeoSoils, Ine.
W.O. 2929-A-SC
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Perched groundwater conditions along fill/formational contacts and along zones of
contrasting permeabilities should not be precluded from occurring in the future due to site
irrigation, poor drainage conditions, or damaged utilities. Should perched groundwater
conditions develop, this office could assess the affected area(s) and provide· the
appropriate recommendations to mitigate the observed groundwater conditions.
Subdrains may be recommended during grading.
The groundwater conditions observed. and opinions generated were those at the time of
our investigation. Conditions may change with the introduction of irrigation, rainfall, or
other factors that were not obvious at the time of our investigation.
Regional Seismic Activity
The seismic acceleration values provided herein should be considered during the design
of the proposed development.
Slope Considerations and Slope Design
All slopes should be designed and constructed irt accordance with the minimum
requirements of the City of Carlsbad, the recommendations in Appendix D, and the
. following:
1. Fill slopes should be designed and constructed at a 2:1 (horizontal to vertical)
gradient or flatter, and should not exceed 20 feet in height without additional slope
stability analysis. Fill slopes should be properly built and compacted to a minimum
.. relative compaction of 90 percent throughout, including the slope surfaces.
2.
3.
Guidelines for slope construction are presented in Appendix D.
Cut slopes should be designed at gradients of 2:1 (horizontal to vertical), and
should not exceed 1 o feet in height without additional slope stability analysis. While
stabilization of such slopes is not anticipated, locally adverse geologic conditions
(i.e., daylighted joints/fractures or severely weathered bedrock) may be
encountered which may require remedial grading or laying back of the slope to an
angle flatter than the adverse geologic condition.
Based upon the information collected as a part of this study, there are no graded
slopes that require buttressing; however, based on the impermeability (i.e., seepage
potential) and high expansion potential encountered locally in the clayey
topsoil/colluvial soils and siltstone/claystone bedrock, cut slopes associated with
Lot 1 (multi-family lot) may require a stabilization fill with backdrains.
Local areas of highly weathered bedrock may also be present within the property
as a whole. Should these materials be exposed in cut slopes, the potential for long
term maintenance or possible slope failure exists. Evaluation of cut slopes during
Mr. David Bentley
Holly Springs, Carlsbad
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grading would be necessary in order to identify any areas of severely weathered
rock or non-cohesive sands. Should any of these materials be exposed during
construction, the soils engineer/geologist, would assess the magnitude and extent
. of the materials and their potential affect on long-term maintenance or possible
slope failures. Recommendations would then be made at the time of the field
inspection. Further evaluation of slope stability should be conducted at the 40-scale
grading plan stage.
4. Cut slopes should be mapped by the project engineering geologist during grading
to allow amendments to the recommendations should exposed conditions warrant
alternation of the design or stabilization.
EARTHWORK CONSTRUCTION RECOMMENDATIONS
General
1. Soils engineering and compaction testing services should be provided during
grading operations to assist the contractor in removing unsuitable soils and in his
effort to compact the fill.
· 2. Geologic observations should ·be performed during grading to verify and/or further
evaluate geologic conditions. Although unlikely, if adverse geologic structures are
encountered, supplemental recommendations and earthwork may be warranted.
3. In general and based upon the available data to date, groundwater is not expected
.. to be a major factor in development of the site. However, due to the nature of the
site materials, local seasonal seepage may be encountered throughout the site
along with seasonal perched water within any drainage areas.
4. Current local and state/federal safety ordinances for subsurface trenching should
be enforced ..
5. General Earthwork and Grading·Guidelines are provided at the end of this report as
Appendix D. Specific recommendations are provided below.
Demolition/Grubbing
1. Any existing subsurface structures, major vegetation, and any miscellaneous debris
should be removed from the areas of proposed grading.
Mr. David Bentley
Holly Springs, Carlsbad
File: e\wp7\2900\2929a.lge ·
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W.O. 2929-A-SC
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2. The project soils engineer should be notified of any previous foundation, irrigation
lines, cesspools, or other subsurface structures that are uncovered during the
recommended removals, so that appropriate remedial recommendations can be
provided.
Treatment of Existing Ground
1. Existing vegetation and/or deleterious trash and debris should be stripped and
hauled offsite in the areas of proposed development.
2. Removals/reprocessing in areas planned for settlement-sensitive improvements
(including pavement areas) shall consist of all topsoil/colluvium, existing fill
materials (if any), and alluvium. These materials should be removed, moisture
conditioned to at least optimum moisture content, and recompacted and/or
processed in place to a minimum relative compaction of 90 percent of the
laboratory standard (ASTM D-1557). These conditions should be tested by a
representative of our firm.
3. Topsoil/colluvium, existing fill (if any), and alluvium may be reused as compacted
fill provided that major concentrations of vegetation and miscellaneous debris are
removed prior to or during fill placement.
Fill Placement
1. Fill materials should be brought to at least optimum moisture, placed in thin 6-to
8-inch lifts and mechanically c9mpacted to obtain a minimum relative compaction
·· of 90 percent of the laboratory standard.
2. Fill materials should be cleansed of major vegetation and debris prior to placement.
3. Any oversized rock materials greater than 1'2 inches in diameter should not be
placed within the upper 3 feet of the proposed foundation, and the upper 12 inches
of finish grade materials on pads should consist of 6 inch and minus earth materials.
4. Any import materials should be observed and determined suitable by the soils
engineer prior to placement on the site. Foundation designs may be altered if
import materials have a greater expansion value than the onsite materials
encountered in this investigation.
5. Should significant amounts of rock be generated, recommendations for rock fills
can be provided .
Mr. David Bentley
Holly Springs, Carlsbad
File: e\wp7\2900\2929a.lge
GeoSoils, Jne.
W.O. 2929-A-SC
October 11, 2000
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Overexcavation
Proposed grading of the building sites may create a cut/fill transition in the building pad
area where bedrock is juxtaposed against proposed fill. In such areas, the bedrock should
be overexcavated to a depth of 3 feet, or the minimum depth as defined within the
removals section presented above, whichever is greater. Overexcavation should be
completed for a minimum lateral distance of 5 feet outside the extreme foundation
elements, or a 1: 1 projection from the bottom of the footing, whichever is greater. If footing
embedments are greater than 24 inches, the overexcavation should be increased to a
minimum of 2 feet below the bottom of the footing. Based on the conditions disclosed
during grading, overexcavation and laying back of subsurface slopes to an inclination of
3:1 {h:v) or flatter may be required. If the foundation envelopes (i.e., building footprints)
are not finalized as of the date of grading, the entire lot should be overexcavated.
Consideration may be given to overexcavation of hard rock areas to facilitate utility
construction in-street areas, and/or foundation excavation. This is not a geotechnical
~equirement, but should also be considered.
Erosion Control
Onsite soils and/or formational mat~rials have a moderate erosion potential. Use of hay
bales, silt-fehces, and/or sandbags should be considered, as appropriate. Temporary
· grades should be constructed to drain at 1 to 2 _ percent to a suitable temporary or
permanent outlet. Evaluation of cuts during grading will be necessary in order to identify
any areas of loose or non-cohesive materials. Should any significant zones be
encountered during earthwork construction remedial grading may be recommended;
however no remedial measures are anticipated at this time.
RECOMMENDATIONS -FOUNDATIONS
In the event that the information concerning the proposeq development plan (by Ladwig
Design Group) is not correct or any changes in the design, location, or loading conditions
of the proposed structures are made, the conclusions ~nd recommendations contained
in this report are for the subject site only and shall not be considered valid unless the
changes are reviewed and conclusions of this report are modified or approved in writing
by this office.
The information and recommendations presented in this section are considered minimums
and are not meant to supersede design{s) by the project structural engineer or civil
engineer specializing in structural design. Upon request, GSI could provide additional
consultation regarding soil parameters, as related to foundation design. They are
considered preliminary recommendations for proposed construction, in consideration of
our field investigation, and laboratory testing and engineering analysis.
Mr. David Bentley
Holly Springs, Carlsbad
File: e\wp7\2900\2929a.lge
GeoSoils, lne.
W.O. 2929-A-SC
October 11, 2000
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Our review, field work, and laboratory testing indicates that onsite soils have a very low
(expansion index Oto 20} to high expansion potential range (expansion index 91 to 130).
Preliminary recommendations for foundation design and construction are presented below.
Final foundation recommendations should be provided at the conclusion of grading based
on laboratory testing of fill materials exposed at finish grac;te.
Bearing Value
1. The foundation systems should be designed and constructed in accordance with
guidelines presented in the latest edition of the Uniform Building Code.
2. An allowable bearing value of 1,500 pounds per square foot may be used for design
of continuous footings 12 inches wide and 18 inches deep and for design of
isolated pad footings 24 inches square and 24 inches deep founded entirely into
compacted fill or competent formational material and connected by grade beam or
tie beam in at least one direction. This value may be increased by 20 percent for
each additional 12 inches in depth to a maximum value of 2,500 pounds per square
foot. The above values may be increased by one-third when considering short
duration seismic or wind loads. No increase in bearing for footing width is
recommended.
· Lateral Pressure
· 1. For lateral sliding resistance, a 0.35 coefficient of friction may be utilized for a
concrete to soil contact when multiplied by the dead load.
· 2. .. Passive earth pressure may be computed as an equivalent fluid having a density of
250 pounds per cubic foot with a maximum earth pressure of 2,500 pounds per
square foot
3. When combining passive pressure and frictional resistance, the passive pressure
component should be reduced by one-third. ·
Footing Setbacks
All footings should maintain a minimum 7-foot horizontal setback from the base of the
footing to any descending slope. This distance is measured from the footing face at the
bearing elevation. Footings should maintain a minimum horizontal setback of H/3
(H=slope height) from the base of the footing to the descending slope face and no less
than 7 feet nor need to be greater than 40 feet. Footings adjacent to unlined drainage
swales should be deepened to a minimum of 6 inches below the invert of the adjacent
unlined swale. Footings for structures adjacent to retaining walls should be deepened so
as to extend below a 1 :1 projection from the heel of the wall. Alternatively, walls may be
Mr. David Bentley
Holly Springs, Carlsbad
File: e\wp7\2900\2929a.lge
GeoSoils, lne.
W.O. 2929-A-SC
October 11, 2000
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designed to accommodate structural loads from buildings or appurtenances as described
in the retaining wall section of this report.
Construction
The following foundation construction recommendations are presented as a minimum
criteria from a soils engineering standpoint. The onsite soils expansion potentials are
generally in the very low range (expansion index Oto 20); however, bedrock materials from
the Santiago formation may range up to the high (expansion index 91 to 130) range.
Recommendations for very low to high expansive soils, there.fore, are presented herein for
your convenience.
. Recommendations by the project1s design-structural engineer or architect, which may
exceed the soils engine~r's recommendations, should take precedence over the following.
minimum requirements. Final foundation design will be provided based on the expansion
potential of the near surface soils encountered during grading.
Very Low to Low Expansion Potential (Expansion Index o to 50)
1. Exterior and interior footings should be founded at a minimum depth of 12 inches
for one-story floor loads, and 18 inches below the lowest adjacent ground surface
for two-story floor loads. All footings should be reinforced with two No. 4 reinforcing
bars, one placed near the top and one placed near the bottoni of the footing.
Footing widths should be as indicated in the Uniform Building Code (International
Conference of Building Officials, 1997).
.. 2. .. A grade beam, reinforced as above, and at least ~2 inches wide should be provided
across large (e.g. doorways) entrances. The base of the grade beam should be at
the same elevation as the bottom of adjoining footings.
Residential concrete slabs, where moisture condensation is undesirable; should be
underlain with a vapor barrier consisting of a minimum of 6 mil polyvinyl chloride or
equivalent membrane with all laps sealed. This membrane should be covered
above and below with a minimum of 2 inches of sand (total of 4 inches) to aid in
uniform curing of the concrete and to protect the membrane from puncture.
4. Residential concrete slabs should be a minimum of 4 inches thick, and should be
reinforced with No. 3 reinforcing bar at 18 inches on center in both directions, or 6x6
-W1 .4 x W1 .4 welded wire mesh. If welded wire mesh is selected, No. 3 reinforcing
·bar at 18 inches on center should be doweled between the exterior footing and 3
feet into the slab. All slab reinforcement should be supported to ensure placement
near the vertical midpoint of the concrete. 1Hooking11 the wire mesh is not
considered an acceptable method of positioning the reinforcement.
Mr. David Bentley
Holly Springs, Carlsbad
File: e\wp7\2900\2929a.lge
GeoSoils, lne.
W.0. 2929-A-SC
October 11, 2000
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5. Residential garage slabs should be reinforced as above and poured separately from
the structural footings and quartered with expansion joints or saw cuts. A positive
separation from the footings should be maintained with expansion joint material to
permit relative movement.
6. Presaturation is not required for these soil conditions. The moisture content of the
subgrade soils should be equal to or greater than optimum moisture content in the
slab areas. Prior to placing visqueen or reinforcement, soil moisture content should
. be verified by this office within 72 hours of pouring slabs.
Medium Expansion Potential (Expansion Index 51 to 90)
1. Exterior and interior footings should be founded at a minimum depth of 18 inches
for one-story loads, and 24 inches below the lowest adjacent ground surface for
two-story loads. All footings should be reinforced with two No. 4 reinforcing bars,
_one placed near the top and one placed near the bottom of the footing. Footing
· widths should be as indicated in . the Uniform Building Code (International
. Conference of Building Officials, 1997).
2. A grade beam, reinforced as above, and at least 12 inches wide should be provided
across large (e.g. doorways) entrances. The base of the grade beam should be at
the same elevation as the bottom of adjoining footings.
3. Concrete slabs, yvhere moisture condensation is undesirable, should be underlain
with a vapor barrier consisting of a minimum of 6 mil polyvinyl chloride or equivalent
membrane with all laps sealed. This membrane should be covered above and
.. below with a minimum of 2 inches of sand (total of 4 inches) to aid in uniform curing
of the concrete and to protect the membrane from puncture.
4. Concrete slabs should be a minimum of 4 inches thick, and should be minimally
reinforced with a No: 3 reinforcing bar at 18 inches on center. A No. 3 reinforcing
-bar at 18 inches on center should be doweled between the exterior footing and 3
feet into the slab. All slab reinforcement should be supported to ensure placement
near the vertical midpoint of the concrete. 11Hooking11 the wire mesh is not
considered an acceptable meth~d of positioning the reinforcement.
5. Garage slabs should be reinforced as above and poured separately from the
structural footings and quartered with expansion joints or saw cuts. A positive
separation from the footings should be maintained with expansion joint material to
permit relative movement.
6. Presaturation is recommended for these soil conditions. The moisture content of
the subgrade soils should be equal to or greater than 120 percent of optimum
moisture content to a depth of 18 inches below grade in the slab areas. Prior to
Mr. David Bentley
Holly Springs, Carlsbad
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placing visqueen or reinforcement, soil presaturation should be verified by this office
within 72 hours of pouring slabs.
High Expansion Potential (Expansion Index 91 to 130)/Preliminary Post-Tensioned
Slab Foundation Systems
Post.,tensioned (Pn slabs may be utilized for construction of typical one-and two-story
residential structures onsite. PT slabs are required for an expansion potential of 91 or
greater. The information and recommendations provided herein are not meant to
supersede design by a registered structural engineer or civil engineer familiar with PT slab
design.
From a soil expansion/shrinkage standpoint, a fairly common contributing factor to distress
of structures using post-tensioned slabs is a significant fluctuation in the moisture content
of soils underlying the perimeter of the slab, compared to the center, causing a "dishing"
or "arching" of the slabs. To mitigate this·possible phenomenon, a combination of soil
presaturation (if necessary, or after the project has been dormant.for a period of time),
and/or construction of a perimeter "cut off' wall grade beam should be employed.
For high (El 91 to 130) expansive soils, perimeter and mid-span beams should be a
minimum of 24 inches deep below lowest adjacent pad grade. The perimeter foundations
· may be integrated into the slab design or independent of the slab. The perimeter beams
should be a minimum of 12 inches in width .. In moisture sensitive slab areas, a vapor
barrier should be utilized and be of sufficient thickness to provide an adequate separation
of foundation from soils (6 mils thick). The vapor barrier should be lapped and sealed to
provide a continuous water-resistant barrier under the entire slab. The vapor barrier shou.ld
.. be sandwiched between two 2-inch thick layers of sand (SE>30} ..
Specific soil presaturation for slabs is required for ·high to very high expansive soils;
however, the moisture content of the subgrade soils should be. at or above the soils
optimum moisture content to a minimum depth of 24 inches below grade depending on
the footing embedment.
Post-tensioned slabs should be designed using sound engineering practice and be in
accordance with the Post-Tensioned Institute (PTI) local and/or national code criteria and
the recommendations of a structural or civil engineer qualified in a post-tensioned slab
design. Alternatives to PTI methodology may be used if equivalent systems can be
proposed which accommodate the angular distortions, expansion parameters, and
settlements noted for this project. If alternatives to PTI are suggested by the structural
consultant, consideration should be given for additional review by qualified structural PT
designer.
Mr. David Bentley
Holly Springs, Carlsbad
File: e\wp7\2900\2929a,lge
GeoSoils, Ine~
W.O. 2929-A-SC
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Perimeter Footing Embedment* 24"
Percent Clay 40%
Percent Passing #200 Sieve 85%
~llowable Bearing Value 1000 psf*
Modulus of Subgrade Reaction 75 psi/inch
Coefficient of Friction 0.30
Passive Pressure 225
* Internal bearing value within the perimeter of the
Post-Tensioned slab may be increased by 20%
(200 psf) for each foot of embedment (beyond 6"
surface subgrade) to a maximum value of 2000 psf.
The following table presents suggested minimum coefficients to be used in the Post-
Tensioning Institute design method:
,;<\:, >:~E$iq~,:~~r~oo:,,,tr;:-. --:M1~i~~~i.¢pl:i=fJ~IENT T9 BE USED.
Thornthwaite Moisture Index -20 inches/year
Correction Factor for Irrigation 20 Inches/year
Depth to Constant Soil Suction 5 (feet)
Constant Soil Suction 3.6
Based on the above parameters, the following values were obtained from figures or tables
.. of the Uniform Building Code (1997). The values may_not be appropriate to account for
possible differential settlement of the slab due to -other factors. If a stiffer slab is desired,
higher values of Ym may be warranted.
e~ center lift
em edge lift
Ym center lift
Mr. David Bentley
Holly Springs, Carlsbad
File: e\wp7\2900\2929a.lge
5_.0feet
2.5 feet
1.10 inches
0.35 inches
5.5 feet
2.7feet
2;0 inches
0.5 inches
GeoSoils, lne.·.
5.5feet
3.0 feet
2.5 inches
0.75 inches
5.5 feet
3.0 feet
4.0 inches
1.5 inches
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Perimeter grade beams should be incorporated into the design and should be a minimum
of 24 inches deep. Midspan beams (24 inches embedment) should be incorporated into
-the design of the post-tensioned slabs.
CORROSION
Limited laboratory testing for soluble. sulfates, pH, and corrosion to metals have been
completed. Preliminary laboratory test results indicate that site materials have a negligible
potential for corrosion to concrete (i.e., sulfate content) and a severely high potential for
corrosion to exposed steel (i.e., saturated resistivity). Specific test results were previously
provided in the Laboratory se~tion of this report.
Upon completion of grading, additional testing of soils (including import materials) is
recommended prior to the construction of utilities and foundations. Further evaluation by
a qualified corrosion engineer may be considered. Accordingly, the use of Type V
concrete with a modified water/cement ratio cannot be precluded.
CONVENTIONAL RETAINING WALL RECOMMENDATIONS
· General
The equivalent fluid pressure parameters provide for the use of very low expansive select
granular backfill to be utilized behind the proposed walls. The low expansive granular
backfill, should be provided behind the wall at a 1 :1 (h:v) projection from the heel of the
-· foundation system. Low expansive fill is Class 3 aggregate baserock or Class 2 permeable
rock or suitable site soils tested to be in the very low expansion range during backfilling.
Wall backfilling should be performed with relatively light equipment withi_n the same 1 : 1
projection (i.e., hand tampers, walk behind compactors). Expansive soils should not be
used to backfill any proposed walls. During construction, materials should not be
stockpil~d behind nor in front of walls for a distance of 2H where H is the height of the wall.
Foundation systems for any proposed retaining walls should be designed in accordance
with the recommendations presented in the Foundation Design section of this report.
There should be no increase in bearing for footing width. Building walls, below grade,
should be water-proofed or damp-proofed, depending on the degree of moisture
protection desired. All walls should be properly designed in accordance with the
recommendations presented below. Additional geotechnical design parameters will be
required for specialty walls O.e., Keystone, Leffel, Crib, Geogrid, etc.), and will be provided
upon request, based on their proposed evaluation and use.
Some movement of the walls constructed should be anticipated as soil strength
parameters are mobilized. This· movement could cause some cracking depending upon
the materials used·to construct the wall. To reduce the potential for wall cracking, walls
' '
Mr. David Bentley
Holly Springs, Carlsbad
File: e\wp7\2900\2929a.lge
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should be internally grouted and reinforced with steel. To mitigate this effect, the use of
vertical crack control joints and expansion joints, spaced at 20 feet or less along the walls
should be employed. Vertical expansion control joints should be infilled with a flexible
grout. Wall footings should be keyed or doweled across vertical expansion joints. Walls
should be internally grouted and reinforced with steel.
Restrained Walls
Any retaining walls that will be restrained prior to placing and compacting backfill material
or that have re-entrant or male corners, should be designed .for an at-rest equivalent fluid
pressures (EFP) of 65 pcf, plus any applicable surcharge loading. This restrained-wall,
earth pressure value is for select backfill material only. For areas of male or re-entrant
corners, the restrained wall design should extend a minimum distance of twice the height
of the wall laterally from the corner.
Building walls below grade or greater than 2 feet in height should be water-proofed or
damp-proofed., depending on the degree of moisture protection desired. The wall should
be drained as indicated in the following section. For structural footing loi;ids within the 1 : 1
zone of influence behind wall backfill, refer to the following section.
Cantilevered Walls
These recommendations are for cantilevered retaining walls up to 1 0 feet high. Active
. earth pressure may be used for retaining wall design, provided the top of the wall is not
restrained from minor deflections. An empirical equivalent fluid pressure approach may
be used to compute the·horizontal pressure against the wall. Appropriate fluid unit weights
are provided for specific: slope gradients of the retained material. These do not include
other superimposed loading conditions such as traffic, structures, seismic events,
expansive soils, or adverse geologic conditions.
If traffic is within a distance H behind any wall or a 1 : 1 projection from the heel of the wall
foundation a pressure of 100 psf per foot in the upper 5 feet should be used. Structural
loads from adjacent properties and their influence on site walls should be reviewed by the
structural engineer, if within a 1:1 projection behind any site wall. However, for preliminary
planning purposes, one third of the footing contact pressure should be added to the wall
in pounds per square foot below the bearing elevation and for a distance of three times the
footing width along the wall alignment. Alternatively, a deepened footing beyond the 1 :1
projection (up from the heel) behind the wall may be utilized.
Mr. David Bentley
Holly Springs, Carlsbad
File: e\wp7\2900\2929a.lge
GeoSoils, lne.
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SURFACE SLOPE OF RETAINED EQUIVALENT FLUID WEIGHT FOR
MATERIAL (horizontal to vertical) NON-EXPANSIVE SOIL*
Level** 38
2 to 1 55
*To be increased by traffic, structural surcharge and seismic loading as needed.
**Level walls are those where orades behind the wall are level for a distance of 2H.
Wall Backfill and Drainage
All retaining walls should be provided with an adequate backdrain and outlet system
(a minimum two outlets per wall and no greater than 100 feet apart), to prevent buildup of
hydrostatic pressures and be designed in accordance with minimum standards presented
herein. · The very low expansive granular backfill should be provided behind the wall at a
1 :1 (h:v) projection from the heel of the foundation element. Drain pipe should consist of
4-inch diameter perforated schedule 40 PVC pipe embedded in gravel. Gravel used in the
backdrain systems should be a minimum of? cubic feet per lineal foot of%-to 1-inch clean
crushed rock wrapped in filter fabric (Mirafi 140 or equivalent) and 12 inches thick behind
the wall. Where the void to be fitted is constrained by lot lines or property boundaries, the
use of panel drains (Mirafi 5000 or equivalent) may be considered with the approval of the
project geotechnical engineer. The surface of the backfill should be sealed by pavement
or the top 18 inches compacted to 90 percent relative compaction with native soil. Proper
surface drainage should also be provided. Weeping of the walls in lieu of a backdrain is
not recommended for walls greater than 2 feet in height. For walls 2 feet or less in height,
weepholes should be no greater than 6 feet on center in the bottom coarse of block and
above the landscape zone. .
A paved drainage channel {v-ditch or substitute), either concrete or asphaltic concrete,
behind th~ top of the walls with sloping backfill should be considered to reduce the
potential for surface wat~r penetration. For level backfill, the.grade should be sloped such
that drainage is toward a suitable outlet at 1 to 2 percent.
Retaining Wall Footing Transitions
Site walls are anticipated to be founded on footings designed ih accordance with the
recommendations in this report. Wall footings may transition from formational bedrock to
gravelly fill to select fill. If this condition is present the civil designer may specify either:
a) If transitions from rock fill to select fill transect the wall footing alignment at an angle
of less than 45 degrees (plan view), ther, ,he designer should perform a minimum
2-foot overexcavation for a distance of two.times the height of the wall and increase
overexcavation until such transition is between 45 and 90 degrees to the wall
alitinment.
Mr. David Bentley
Holly Springs, Carlsbad
File: e\wp7\2900\2929a.lge
W.O. 2929-A-SC
October 11, 2000
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b) Increase of the amount of reinforcing steel and wall detailing (i.e., expansion joints
or crack control joints) such that an angular distortion of 1 /360 for a distance of 2H
(where H =wall height in feet) on either side of the transition may be
accommodated. Expansion joints should be sealed with a flexible, non-shrink
grout.
c) Embed the footings entirely into a homogeneous fill.
RECOMMENDATIONS-POST EARTHWORK .
Planting and Landscape Maintenance
Graded slopes constructed within and/or exhibiting or exposing weathered formational
materials are considered erosive. Eroded debris may be minimized and surficial slope
stability enhanced by establishing and maintaining a suitable vegetation cover soon after
construction. ·
Plants selected by the project landscape architect should be light weight, deep-rooted
types that require little water and are capable of surviving the prevailing climate.
· Graded cut slopes exposing less weathered formational materials are expected to be
relatively non-erosive and will present difficulty for establishment of vegetation on the
dense formational materials. Jute-type matting or other fibrous covers may aid in allowing
the establishment of a sparse plant cover.
Water can weaken the inherent strength of all earth materials. Positive surface drainage
away from graded slopes should be maintained and only the amount of water necessary
to sustain plant life should be provided .for planted slopes. Overwatering should be
avoided as overwatering the landscape area could adversely affect the proposed site
improvements.
Additional Site Improvements
Recommendations for exterior concrete flat work design and construction can be provided
upon request,_ after site earthwork is complete. If, in the future, any additional
improvements are planned for the site in general or individual areas, recommendations
concerning the geological or geotechnical aspects of design and construction of said.
improvements may be provided upon request.
Footing Trench Excavation
All footing trench excavations should be observed by a representative of this office prior
to placing reinforcement. Footing trench spoil and any excess soils generated from utility
Mr. David Bentley
Holly Springs, Carlsbad
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trench excavations should be compacted to a minimum relative compaction of 90 percent
if not removed the site.
Drainage
Positive site drainage should be maintained at all times. Drainage should not flow
uncontrolled down any descending slope. Water should be directed away from
foundations and not allowed to pond and/or seep into the ·ground. Pad drainage should
be directed toward the street or other approved area. Due to the nature of on-site soils,
combined with the hardness and permeability of the formational materials, local areas of
seepage may develop due to irrigation or heavy rainfall. Minimizing irrigation will lessen
this potential. If areas of seepage develop, remedial recommendations for minimizing this
effect could be provided upon request.
TRENCH BACKFILL
1. All utility trench backfill in structural areas, slopes, and beneath hard scape features
should be brought to at least optimum moisture content and then compacted to
obtain a minimum relative compaction of 90 percent of the laboratory standard.
Flooding/jetting is not recommended for the site soil materials. As an alternative,
SE 30 or greater sand, may be flooded/jetted in shallow under-slab interior
. trenches.
2. Sand backfill should not be allowed in exterior trenches adjacent to and within an
area extending below a 1 :1 plane projected from the outside bottom edge of the
·· footing.
3. All trench excavations should conform to CAL-OSHA and local safety codes.
PLAN REVIEW
Project grading p!ans should be reviewed by this office as· they become. Based on our
review, supplemental recommendations and further geotechnical studies (i.e., rock
hardness evaluation) will likely be recommended. Further field work will require
disturbance and removal of vegetation.
Mr. David Bentley.
Holly Springs, Carlsbad
File: e\wp7\2900\2929a.lge
GeoSoils, lne.
W.0. 2929-A-SC
October 11, 2000
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INVESTIGATION LIMITATIONS.
Inasmuch as our study is based upon the site materials observed, selective laboratory
testing and limited engineering analysis, the conclusion and recommendations are
professional opinions. These opinions have been derived in accordance With current
standards of practice, and no warranty is expressed or implied. Standards of practice are
subject to change with time.
These opinions have been derived in accordance with current standards of practice, and
no warranty is expressed or implied. St~ndards of practice are subject to change with
time. GSI assumes no responsibility or liability for work or testing performed by others, for
our scope-of-work was expressly limited to the evaluation of the sediments/soils underlying
the proposed residence. In addition, this report may be subject to review by the controlling
authorities.
Mr. David Bentley
Holly Springs, Carlsbad
File: e\wp7\2900\2929a.lge
GeoSoils, lne.
W.O. 2929-A-SC
October 11, 2000
Page27
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APPENDIX A
REFERENCES
Blake, Thomas F., 1997, EQFAULT computer program and users manual for the
deterministic prediction of horizontal accelerations from digitized California faults.
Campbell, K.W. and Bozorgnia, Y., 1994, Near-source attenuation of peak horizontal
acceleration from worldwide accelrograms recorded from 1957 to 1993;
Proceedings, Fifth U.S. National Conference on Earthquake Engineering, volume
Ill, Earthquake Engineering Research Institute, pp 292-293.
Greensfelder, R. W., 1974, Maximum credible rock acceleration from earthquakes in
California: California Division of Mines and Geology, Map Sheet 23.
Hart, E.W., 1994, Fault-rupture hazard zones in California: California Department of
Conservation, Division of Mines and Geology, Special Publication 42.
Housner, G. W., 1 ~70, Strong ground motion in Earthquake Engineering, Robert Wiegel,
ed., Prentice-Hall.
· Idriss, I.M., 1994, Attenuation Coefficients for Deep and Soft Soil Conditions, personal
communication.
International Conference of Building Officials, 1997, Uniform building code: Whittier,
California.
Jennings, C.W., 1994, Fault activity map of California and adjacent areas: California
Division of Mines and Geology, Map Sheet No. 6, scale 1 :750,000.
Petersen, Mark D., Bryant, W.A., and Cramer, C.H., 1996, Interim table of fault parameters
used by the California Division of Mines and Geology to compile the probabilistic
seismic hazard maps of California.
Sowers and Sowers, 1970, Unified soil classification system (After U. S. Waterways
Experiment Station and ASTM 02487-667) in Introductory Soil Mechanics, New
York
Weber, F.H., 1982, Geologic Map of north-central coastal area of San Diego County,
California showing recent slope failures and pre-development landslides: California
Department of Conservation, Division of Mines and Geology, OFR 82-12 LA.
Wilson, K.L., 1972, Eocene and related geology of a portion of the San Luis Rey and
Encinitas quadrangles, San Diego County, California: unpublished masters thesis,
University of California, Riverside.
GeoS~ils, lne.
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UNIFIED SOIL CLASSIFICATION SYSTEM . I CONSISTENCY OR RELATIVE DENSITY
Major divisions I Croup symbols I T>'Pical uames I CRITERIA
-..l! cw Well-paded sravels md gravel-
~ -u sand mixtures. little or no bes a ,. .. :I -ti II ... -c.; .. Poorly ,raded gravels md --.. ~ > ; .§ .. :I GP sn,,el-und mixhires, little or no Standard Penetration Tee-I -;; ~ SU 0 '! : aJz ines Pen:tra.tion l! .. = -.. co 5: I Silty pavels, pavel-uncl-silt Resisuinc: 1' Relative -o ·t11 = "B c!Z CM en -8 8 .s .. miltl1ra {blows/ft) Density 'i IS II 1:! e . --. .:-s c~&:: Clayey gravels, pavel-und-clay l! = cc 0-4 Very loose t,ii miztures
ti 4-10 Loose
:; lit ... u SW Well-paded suds llld gravelly 10-30 Medium 818 0 > a: .. sacla. little or 110 iaes 30-SO Dense = u . .,, = ;.2,; "= II cl~ Very dense = .. 1.,.. Poorly .pded.amk aad gravelly >50
f! -g a~ o SP sands, little or 11G bes
0 ca: :z: :; II '" :I SM s~ suds, 11111d-a1t miltl1ra .. I .. -a.=; ~ r, ; j.5 • 1:1, ..
II.I "" SC. CJayay suds, smd-elay mixtures
-lDOl'pllil: silts, very be 1111ds, ML rock lour, silty or clayey ine .. sads
.. u j'== ..
> u!.! biorpDic clays o£ Jaw ta .. u -gi· a -CL medium plutic:ity, gravelly Standard Penetration Test
~1 ·=; clays, sandy clays, silty clays, -a! Penetrauon Unconfined Compressive
0 leuulays ·
en ci en Resistance N Strength "'B 2: = a OL Orpiic lilts md orpnic silty {blows/ft) Consistency (tons/ft')
~l clays oI law plutidty
0 ! lDorpaic silts. miclceoul. or <2 Very soft <0.25
.5 0 .. Ill MB diaomeceo'U Jme suds or silts, 2-4 Soft o~.so "-Ii ... -~=JB elutic silts 4-8 Medium O.S0-1.00 0 OJ Ii ll1l 8-15 Stiff' 1.00-2.00 i 1':S?'= Inorpaic clays of'hip plasticity, . = .. CH mt clays 15-30 Very stiff 2.00-4.00 !I C' u =:Ji ~30 Hard >4.00 en .. Orpnic clays o£ medium to Ill OH hish. pluticlty I I
..
Highly 0rpmc Soils Peat, mudc, and other highly FI' orpniclOil, i
3• 311.• •4 •,o •40 # . 200 U.S. Standard sieve . I Unified I I Gravel I . Sand . I Silt or Clay I sail ctosslf. Cobbles I coarse I fine · lcoars• I medium I fine 1. -
MOISTURE CONDITJ;ONS MATERAIL QUANTITY OTHER SYMBOLS
Dry &b•nce af' aatat; dullty, dry ta the toucn trace 0 -5 S C core 11111Utle
S119htly below opttaua aoiature content _few 5 -10 S s SPT auple
II0111t for ccmpac:1:icn
Motet near optia\a aoilltura cantant little 10 -zs s B Bulk UIIPl•
V~ry·1101at abOve optiaua aotlltura content --25 -<4!5 1' .w. Groundwater
Wet viaible frN .water, below water table
BASIC LOG FORMAT:
Or-auP naaae, arouo •Y•bol, (Grain aizel, Colar, Mo1111:ure, can•tatency or relative aenaity
Additional conN1nta: oder, preHnce of roota, m;ca, 9yp11U11, coar•• grained carticl••,•tc.
EXAMPLE:
Sand (SP), fine to .. diua 9ratned, brown., 110ist. looH, trace silt, little fine gravel
few cobble• up t~ 4M in atze, 11C1N hair roata and rootlet•
... ...
-------------------
TEST
PIT
NO.
TP-1
lP-2
•
LOG OF EXPLORATORY TEST PITS
w.o. 2929-A.:sc
Holly Springs
September 19, 2000
_·:.( . .. ' \\ ~x;~si:~·#L~J% IJ1JJ:If'.~~lD:'.1t~;: ;lf{~t~if~}!; }~s~;;~
DEPTH ·' _ .. GROUP,_ .:, ···r ,~E,f:)1'.J:i.;.:'' S.::' {);M~:?,f~'.!:,\,!-fl~;:~, :;1·,-c' }).~Y,.,.;~{t1:. :;<(f1fli,::-,;,,,,1, {ft.) : SYMBOL·:. .i' ·o 1-:,_.: (ft,),;,.-;?;\ ·;(:,f.if:t {%},;~;';"::-df":i rt DENSITY;?>' :(fsf;/>·',g;-\*1-·
.. :-,, .. (~~t{~1~~r~r~1:ti~:i~i~if 1f ~~t!i~;\:}::?;:1it··· ,. ·--DESCRIBTIOtl~i,,-;,'" ....... » · ,,,. ,.,.., .... , --,,.\,, ··
.... r,l~J~{f;ttJ~~lii&~i;1iff ,:{?f }lt
0-1 SM
1-2
2-3
0-3 SM
3-7
_,__ .... ··~_-:;../_,;;t::~f:._::fi;S2 ;;,;fl\:·.!;;_:,.z~/\?i:S/ :1/iJ ·~0·'·· J3l -~~~i~ii¾J;s;,;-_
BULK@0-1
BULK@3-4
COLLUVIUM/TOPSOIL: SIL TY SAND with cobbles and
boulders, reddish brown, dry, loose; roots.
WEATHERED GRANITICS: GRANITE, reddish brown, dry,
loose.
Refusal@3'
No groundwater encountered
Backfilled.9-19-00
COLLUVIUM/TOPSOIL: SILTY SAND, brown, dry, loose;
orous, blocky, roots and .rootl~ts.
DECOMPOSED GRANITE (Kgr): DECOMPOSED GRANITE,
yellowish brown, dry, medium dense; blocky, orang iron
oxide staining, dense with depth.
Refusal@?'
No groundwater encountered
PLATE B-1
----------~--------
TEST
PIT
NO.
TP-3
TP-4
. DEPTtt
(ft.)
0-2
2-8
8
0-1½
1½.
•
LOG OF EXPLORATORY TEST PITS
W.0. 2929-A-SC
Holly Springs
September 19, 2000 .
~~?{:' 1\~~1rf t l!Ji;iit~f ll!llill;A\f [ii~f !f ~iJI/I1f \::
SM
SM
COLLUVIUM/TOPSOIL: SILTY SAND, light brown to gray,
drv, loo~e; blocky, roots and rootlets.
DECOMPOSED GRANITE (Kgr): DECOMPOSED GRANITE,
ellowish brown, damp to moist, medium dense.
DECOMPOSED GRANITE, yellowish brown to gray, damp,
dense.
Total Depth = 81
No groundwater encountered
Backfilled 9-19-00
COLLUVIUM/TOPSOIL: SIL TY SAND, reddish brown, dry,
loose.
SANTIAGO PEAK VOLCANICS (Jsp): GRANITE, light
brown, dry, verv dense.
Refusal @ 1 ½'
No groundwater encountered
PLATE B-2
----=-;-, ---·-------------
TEST
PIT· . DEl>TH ..
NO. (ft.)
TP~S 1 0-2 I SM
2-3
TP-6 0-2½ SM
2½-5
•
LOG OF EXPLORATORY TEST PITS
W.O. 2929-A-SC
Holly Springs
September 19, 2000
COLLUVIUM/TOPSOIL: SILTY SAND, orange brown, dry,
loose; blocky, porous, roots and rootlets.
SANTIAGO PEAK VOLCANICS (Jsp): GRANITE, yellowish
brown, dry, verv dense.
Refusal@3'
No groundwater encountered
Backfilled 9-19-00
COLLUVIUM/TOPSOIL: SIL TY SAND with cobbles and
boulders, reddish brown, dry, loose.
SANTIAGO PEAK VOLCANICS (Jsp): GRANITE, light
brown to oray, dry, verv dense.
Refusal @ 2½'
No groundwater encountered
PLATE 8-3
-------------------
•
LOG OF EXPLORATORY TEST PITS
W.O. 2929-A-SC
Holly Springs
Septemper 19, 2000
!f 01iT~ .· ~iLi i !~1~i11 i~f iiZii~ill,t ~ itiiiiiitiii;itiiiiilt[~~;~;;:;;i
TP-7 I 0-2 I I I I I COLLUVIUM/TOPSOIL: SILTY SAND, brown, dry, loose;
2-3
TP-8 0-1
1-3
porous!J:>I~. roots and rootlets.
SANTIAGO PEAK VOLCANICS (Jsp): METAVOLCANICS,
light brown to gray, dry, very dense.
Refusal@3'
No groundwater encountered
Backfilled 9-19-00
COLLUVIUM/TOPSOIL: $ILTY SAND, brown, dry, loose;
bloc~ roots 1;tn.d rootlets.
SANTIAGO PEAK VOLCANICS (Jsp): GRANITE, yellowish
brown,_ dry_!_dens~_to vert_ dense.
Practical Refusal @ 31
Truck hoe may penetrate
i:t ..... lrfillon 9-19-nn
PLATE B-4
-------------------
••
TfST I .. L .\· .. :·
PIT
NO. I (ft.).
TP-9 I Q.:4 SM
4-7 SM
7-10
LOG OF EXPLORATORY TEST PITS
W.O. 2929-A-SC
Holly Springs
September 19, 2000
... ,:~~~:~:§~~~:~~i!~~{~re~r~t~~~~I~t~;2~I~f~~~tts~1iK~~l{;;?T\\:t:f ;,:
4':)i!;,~:.:;,~~"'.'11'"'"-:J'/.,r-,,DESCRIPTION·,:cr.: ,,. t· oJ,,;-:,.;;,-:.·-r:·,.:•: ;-,k -·~ ,·, <·:,
• " " > .•••• 1~!,~§4i~~¥:~~~:7:'.~'.~~·/~~~?'.:~::~;
COLLUVIUM/TOPSOIL: SIL TY SAND~ brown, dry, loose;
roots and rootlets, blocky, porous.
SIL TY SAND, yellowish brown, damp to moist, medium
dense; borous.
SANTIAGO FORMATION (Tsa): SANDSTONE, yellowish
brown to olive gray, moist, medium dense; interbedded
siltstone and clayston~.
Total Depth = 1 O'
No gi"oundwat~r encountered
PLATE B-5
--------------~----
TEST
PIT
NO.
TP-10
DEPTH.'
(ft.) :
0-4
4-5
5-10
•
LOG OF EXPLORATORY TEST PITS
W.O. 2929-A-SC
Holly Springs
September 19, 2000
·.··GROUP<· ·'7• : DEPTH,,.,,,,: .)MOISTURE'.'' h:1'"'ORY',..";,9 ".'}?°"'·"·"·'' ,;,,·.:·:,1:;;•co:',<~'-~~-'31'"'101T:; DESCRIPTION"'·-'('""''''',: s ,, .. ·· .. -..:, .,,,,._,,, ' ',.-:, . : ~. <;.· ~AM;Pt#}~-\,, ,~~~1/,:?i~2f}f :r::; :iji{~l~}1~ ~1lti?~¾~ t};Jiif ;f t~~~$.!f?:-:!.:iN¥Jf f:;iJJl\i.;~~~ir:l;::f)\11tJ. ;::·· .):f i~r:~ ~:i.
'.~YM~~L~:'_ ~:~;~,}~¥\~;f ~. i·'.;1'.~~~~i~' ~~~~lm~i ~r~iif f t~~tlf ~{~~~~f {f~~.i~:~~·i:§ir:H~1S·i~;:tc-;sw::::
Sm
SM
SP
COLLUVIUM/TOPSOIL: SILTY SAND, brown, dry, loose;
blocky; roots and rootlets.
SILTY SAND, reddish brown to olive brown, damp to moist,
loose; porous.
SANTIAGO FORMATION (Tsa): SANDSTONE, light brown
to olive brown, moist to wet, medium dense; interbedded
siltstone and cl~ystone.
Total Depth = 101
No Groundwater encountered
'---•~:U-..1 9-19-00
PLATE B-6
-----------------------
•
LOG OF EXPLORATORY TEST PITS
W.O. 2929-A-SC
Holly Springs
September 19, 2000
TEST . ,. . . ·.SAMPLE',., ,,. .. , ... , .... ·--·., .,, · ... ,, ,,,,.,.,FIELD' .... ,. ,,; , .. ~--:· , .. ,· ,.,;.t.-;,-;,,, ··"'.v:,,··.'··"'" ,,1::,·, f, ... , • " .,. .,.i, ,.-.,. ·' ,.,
PIT DEPTH : GR~u~ :_~Y ·:_--;-:\QEPI~:/~/ :;l~~i~i:~fl~::.~· ~ff:!;~~~ijvi~f:;: ¾:/~[jt:it}~)}t;{][~lii:i;~~§~~~(;i1·~~)~f:l~:J\/{.·:~_;'.:(;'.:,'
. ·.. . . Ii .. '. ',_ . .j-.... ~:,:. : ·~:-;I:,,:·.:·'.?:.:(::·. ·;<\:!'..l;;(.--· -'--; ._, ·.; . .,-:,;· ;ff .. ·.<f.1-,-> .;' :··;t·,.;, ·:;·\:;\,;;.,, ·.l:·;;:,--;:, . :. -·:~ ... ":<: ., ____ .. ·;.;·; , .... ::,_ ·;,:{.,-... ,.>t · "
NO (ft)· . SYMBOL·.'.' ~-·::< (ft y(:;_,_,:,; ·S-,,.' i.'(·'(%) ~"'"·< :."DENSITY'''· i;'.t-il!\~:P!,:lf,k;\;',,-;.","''~-:.::;~::'.;v:,1··',f;!,'ir,\,.~,·:'::,:,;;);,;i: ,, ; .. ; ,:,,::,.,;.-· :'' ', .:·: .,_ ':
. . ·· _.:, · · ·--~~~ ·L_:.:::<l~ .. ~ .... --,:}::·E-·· -~~--~:~-~£?::t:_i ~(::~~i~j: ·;_:~r~-t~n~:: !J.· t.~~:~~-;t::rn:;~-~:{~~trr~~J£i~j'::).;;~~~~~<~-~;;);:.;:~ry:·;:;r{:.-t,~:;-;::.: ·.
TP-11 I 0-2 I I I I I COLLUVIUM/TOPSOIL: SIL TY SAND, brown, dry, loose;
2-3
3-8
blockv, ~orous, roots.
SILTY SAND, reddish brown, moist, medium dense.
SANTIAGO FORMATION (Tsa): SANDSTONE, light
yellowish brown, moist, medium dense; int_erbedded siltstone
· and clavstone~
Total Depth = 8'
No groundwater encountered
PLATE B-7
,_,;
"-· ,_,
;i"'
·,._t f ,•:'
,. ..
'·.:·
( ..
;, .. _ .···''
;'
-, •••• ~ •·' i -• ' ' •
-,, :· . ,, .,
' • , >~
.. ~ . -;::-: ,.,
~'I-!'' :
,;
l ', -. ~-
' . ~ ~ } ~ .. •, ",•,\\,:I,
,'•', ',
·-:., . '~.' ' ;
_I .... ,
-,,· _ ..
··,, ,.
., . -,
·, .. ,
.,• .
•.tr·.:.
/,'
1,·,
. ', ~,
··'·.:;
-~ .. ' '','"
. -. ~ .
.• . ~·,
·,, ..
. , . .: -
''
"' '~
! -,:
'. I \.:
'}
__ ./·'
, '
',·
,_,.
·', ,-
,.
,,., ,, .
·.· ,,
.....
.,· ,,·
.. :_ <.; ·, .,
: ·,
L "., ~,
. ',', -l :
, .. :.,
·,,
. ·",.,
., .-~ .
c'--,, • T,
~', ,,· ...... , ,,..,
. ' ~:.. •.
.:'.:•·,·
' ,, ~ ... ·--. 1,: ~' ,, '• , .
_:,,. . ;:, .. :-.' ...
. •, .. --'.' . :,,·
.:f ·. ,• •:c ,.;:.,_,1 ••
_,'-·
'·1.·•
:.:.·
"! ::--·::. ,..:(--
. :·· '•',
' ~ . ' . ,
I ,•.i
...... -~ .. ~ .. --._. ~ ·r .:. :. :t .·
''.
;_,_ ~ .~ •,' ' ' • I '_," .• ... • ' ··,f .. y
l -~: :--, ' -:,, • "
I
I
I
I
I
I
I
I
1·
I
I
I
I
I
I
I
I
I
I
SL-1
CALCULATIONS
1st Layer (T1) = R1 X D1 Where:
. 2nd Layer (T2) = R2 x (D2 -(C1 x T1)) Where:
3rd Layer (T 3) = R3 X (D3 -(C1 X T1)+(C2 X T ~) Where:
4th Layer (T 4) = R4 X (D4 -(C1 X T1)+(C2 X T2)+(C3 X T3)) Where:
Seismic Velocity/Depth Summary
NE SW
Depth (ft). Velocity (fps)
0 -3.9 1136
3.9 -23.1 4667
23.1 -#11## . 6000
'#### -'#### 0
.. #11## -+ 0 +
SW NE
Depth (ft) Velocity (fps)
0 -2.1 1316
2.1 -19.7 4761
19.7 -#11## 6000
#11## -'#### 0
'#### -+ 0 +
I V=1,136-1,316 I· NE SW i
10' 10' -I V = 4,667 • 4,761 I -
20' 20'
.,,....--
30' 30' --
40' I V ~ 6000 I 40' --
.50'. 50' --
I SCHEMATIC CROSS SECTION l
W.O. 2929-A-SC
R1 = Velocity (fps) Ratio Factor (V2:V1)
D1 = Critical Distance
R2= Velocity (fps) Ratio Factor (V3:V2)
D2= Critical Distance
C1 = Distance Correction Value (V3:V1)
R3= Velocity (fps) Ratio Factor (V4:V3)
D3= Critical Distance
C1 = Distance Correction Value (V4:V1)
C2= Distance Correction Value (V4:V2)
R4= Velocity (fps) Ratio Factor (V5:V4)
04= Critical Distance
C1 = Distance Correction Value (V5:V1)
C2= Distance Correction Value (V5:V2)
C3= Distance Correction Value (V5:V3)
V1 = Seismic Velocity (fps) of 1st Layer
V2 = Seismic Velocity (fps) of 2nd Layer
V3 = Seismic Velocity (fps) of 3rd Layer
V4 = Seismic Velocity (fps) of 4th Layer
SL-1
NE-SW SW-NE
D 10 5.5
D2 110 105
D3
D4 -.. ·V1 1136 1316
V2 4667 4761
V3 6000 6000
V4 vs
i~!~ltti{;~~~ii;i~~~ft:~~iii
T1 3.90 2.07
T2 19.18 17.66
T3 '##### '#####
T4 '##### '#####
T1+T2 23.08 19.73
T1+T2+T3 '##### '#####
T1+T2+T3+T4 '##### '##11##
Plate No. C-1
-· -----
60.0
55.0
50.0
45.0
V3 > 6,000fps I
_/_
L I
I
40.0 I
J
I -CJ 35.0 Cl)
/_
•-L .-. -~
en . -:!!: -~
Cl) ~
E 30.0 -
i=
G> e 2s.o
t-
--~
~ . L, .u --·~
20.0
15.0
, ---10.0 -I _I .:> ,__
1,.---
/ , n
L
5.0 L • , , •wt , ...
0.0 " ~ I V1 -1,136fps
NE
0
~ ~
Traverse Date: 9/7/00
Orientation: N 37 E
10 20
-----·-------Seismic Traverse
.,
'
' _J V3 > 6,000fps -assumed I .
-
I
I
' I
.l. -. --~ I .., ... ....--~ -
~ -· •V ---:.e. ':'I
~ ·~ ---_., ..,. _,._.., -------.. tl _.., ---'". n
~ ---· ~ ... ~ "' ..,
-~ --:;. ·-
___[ _.,_ • _.v ---" I ~ ·-
~ I .~ ... __] 4 ---Ill-~-,-.v \ ~
\
\
I V2 4,667fps I
I
I
I
30 40 50 60 70
Distance to Geophone {feet).
Traverse No.: SL-1
-·-
_11 -.
~
~ " ... -~
r ~
I
L
I __!_ I
I V2 -4,761fps : I
I _J
I I V1
80 90
. ..,,
-~
~
~
1,316fpS I
100
' ' -~-3 s--
.,,,-~
I I '-I I
I
110
~ ~
' '
120
SW
W.O. 2929-A-SC
Plate No. C-1 a
-
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
·1
I
SL~2
CALCULATIONS
1st Layer (T1) = R1 X D1 Where:
·2nd Layer (T2) = R2 X (D2 -(C1 X T1)) Where:
3rd Layer (T 3) = R3 X (03 -(C1 X T1)+(C2 X T2)) Where:
4th Layer (T 4) = R4 X (D4 -(C1 X T1)+(C2 X T2)+(C3 X T3)} Where:
Seismic Velocity/Depth Summary
N s
Depth (ft} Velocity (fps)
0 -3.5 1163
3.5 -20.5 3774
20.5 -##II# 6000
##II# -##II# o
##II# -+ o +
s N
Depth (ft} Velocity (fps)
0 -5.0 1210
5.0 -11:s 3333
17.5 -##II# 6000
"##II# -##II# 0
"##II# -+ 0 +
N I V = 1,163 -1,210 I s •
10' 1'0' ---I V = 3,333 -3,774 I -
20' 20' -
I 30' I V;:: 6000 30'
-"------
40' 40' --
50' 50' -______,
I SCHEMATIC CROSS SECTION ~
W.O. 2929-A-SC
R1 = Velocity (fps) Ratio Factor (V2:V1)
D1 = Critical Distance
R2= Velocity (fps) Ratio Factor (V3:V2)
D2= Critical Distance
C1 = Distance. Correction Value (V3:V1)
R3·= Velocity (fps) Ratio Factor (V4:V3)
D3= Critical Distance
C1 = Distance Correction Value (V4:V1)
C2= Distance Correction Value (V4:V2)
R4::,; Velocity (fps) Ratio Factor (V5:V4)
D4= Critical Distance
C1 = Distance Correction Value (V5:V1)
C2= Distance Correction Value (V5:V2)
C3= Distance Correction Value (V5:V3)
· V1 = Seismic Velocity (fps) of 1st Layer
V2 = Seismic Velocity (fps) of 2nd Layer
V3 = Seismic Veloci_ty (fps) of 3rd Layer
V4 = Seismic Velocity (fps) of 4th Layer
SL-2
N-S S-N
D 9.5 14.5
D2 73 49
D3
•' ,·· ·D4 ... · .· .. -
V1 1163 1210
V2 3774 3333
V3 6000 6000
V4
vs
i~~~~~~lil~~~ltli~!Jii~~~i~!~~i~~:
T1 3.45 4.96
T2 17.09 12.55
T3 ##11## ##11##
T4 ##11## '##11##
T1+T2 20.55 17.51
T1+T2+T3 ##11## ##II##
T1+T2+T3+T4 ##11## ##11##
Plate No. C-2
---------------------
60.0
55.0
50,0
45.0
40.0 1--f Va > 6,000fps
I -u 35,0 a, -
Cl) ,.
:::ilii -,A "'
G> E 30.0
i=
-· . -''" .o "IC • --··
G> > 25.0 e -
t-
20.0 -
·15.0 -I -I -,, ,;j
'--.
10.0 / -.. n ..
/ ....... \ ... nln \ , __ ~ -·-\
/ \
5.0 / \
Ii I V2 = 3,774fps : ~ I
7~1:i I
7~-v, 1,163fps : I 17 -I 0.0
N
0
~ ~
Traverse Date: 9/7/00
Orientation: N -S
10 20 30 40
-
Seismic Traverse
'
---· ·" ~-.o .--~ --"' . -, ~
~ .:.· ~
!j 4, '..I! _:i
~ ~ ·-.-.-•a .... ---' "' ~ -1l ..... _, -. --J -.LI .;;) -._ -I r-.. 1, ,.3'
.II,
I
I
I
I V2 = 3,333fps 1
I
I I
I
I
I
50 60 70 80 90
Distance to Geophone (feet)
Traverse No.: SL-2
1 V3 > 6,000fps ----
-' -
-
'--~-~0_1--. ·-I
I LI .:> -·--
z ,.4
-' ,•.::, -' ----L ~j4 I
I
--,_
' ' ~
'" ",4 1-
I ....._
I ~·-~~
: v, 1,210fps : I '\. -
100 110 120
ID= 14,5 I D =49
s
W.O. 2929-A-SC
Plate No. C-2a
I
I
I
I
I
I
I
·I
I
I
I
··I
I.
I
I
I
I
I
I
SL-3
CALCULATIONS
1st Layer (T1) = R1 X D1 Where:
2nd Layer (T2) = R2 X (D2 • (C1 X T1)) Where:
3rd Layer (T 3) = R3 X (D3 • (C1 X T1)+(C2 X T2)) Where:
• 4th Layer (T 4) = R4 X (04 • (C1 X T1)+(C2 X T2)+(C3 X T3)) Where:
.
Seismic Velocity/Depth Summary
N.E SW
Depth (ft) Velocity (fps)
0 -3.0 1087
3.0 -15.7 3750
15.7 -##### 6000
#### -##### 0
.. #If:## .; + 0 +
SW NE
Depth (ft) Velocity (fps)
0 -3.2 1136
3.2 -15.1 5263
15.1 -##### 6000
#### -##### 0
#### -+ 0 +
NE I V=1,087-1,136 I SW
' 10' I V= 3,750 I -----10' I V=S,263 I------20' 20' --I V 2: 6000 I 30' 30' --
40' 40' ·--
50' 50' --
I SCHEMATIC CROSS SECTION l
W.O. 2929-A-SC
R1 = Velocity (fps) Ratio Factor (V2:V1)
D1 = Critical Distance
R2= Velocity (fps) Ratio Factor (V3:V2)
D2= Critical Distance
C1 = Distance Correction Value (V3:V1)
R3= Velocity (fps) Ratio Factor (V4:V3)
03= Critical Distance
C·1 = Distance Correction Value (V4:V1)
C2= Distance Correction Value (V4:V2)
R4= Velocity (fps) .Ratio Factor (V5:V4)
D4= Critical Distance
C1 = Distance Correction Value (V5:V1)
C2= Distance Correction Value (V5:V2)
C3.= Distance Correction Value (V5:V3)
V1 = Seismic Velocity (fps) of 1st Layer
V2 = Seismic Velocity (fps) of 2nd Layer
V3 = Seismic Velocity (fps) of 3rd Layer
V4 = Seismic Velocity (fps) of 4th Layer
SL-3
NE-SW SW-NE
D 8 8
D2 54 94
D3
04. ... -
V1 1087 1136
V2 3750 5263
V3 6000 6000
V4 vs
~~ti~mi~i~~~i~~~t~1~~;~~~t~~iif
T1 2.97 3.21
T2 12.71 11.86
T3 ##### #####
T4 ##### #####
T1+T2 15.68 15.08
T1+T2+T3 #11#11# ###11#
T1+T2+T3+T4 ###11# #####
Plate No. C-3
----------·---------· ~I,,,, ..
'{::1
;-~-~ .
60.0
55.0
50.0
45.0
40.0
-g 35.0
V3 > 6,000fps : ,_ ,_
Cl) :'!: -GI E 30.0 I
i=
a; l2 -~ -· -L ,I .--~ . > f! 25.0 ---..
I-
20.0
15.0 ,
/
/
10.0 . ,
~ -/1-
~I
/
5.0 /
-As ·-
0.0
NE
/ r
0
~· ~
Traverse Date: 9/7/00
Orientation: N 15 E
--
10
-
·---~ • 1
.
V1 -1,087fps 1
20 30
L, ,j
~
~
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Seismic Traverse
r
'
:JI .Ii -~ ---I .,, : .... -·-
-· ,t --1-,1 -I -1, ';I , ' . I
I .._
'\. -'\
I V2 3,750fps l I
4,
I
I/
I
I I V2 5,263fps h
I I
I I I I
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40 50 60 70 80
Distance to Geophone (feet)
Traverse No.: SL-3
-I -· ;v
.::::,
"'I .ti
~ l'O.t ---
I I
I
I I V1 I ·1 I
90
I
I V3 > 6,000fps I ~
I
\
\
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l.i ..
I -..:: :6
?; :3
~ ·-
t
----' ----' 4 L_
' I I 1 , 1,1i~ i -p~
100 110
~ ~
120
SW
W.O. 2929-A-SC
Plate No. C-3a
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SL-4
CALCULATIONS
1st Layer (T1) = R1 X D1 Where:
2nd Layer (T2) = R2 X (D2 • (C1 X T1)) Where:
3rd Layer (T 3) = R3 X (D3 -(C1 X T1)+(C2 X T2)) Where:
4th Layer (T 4) = R4 X (D4 -(C1 x T1)+(C2 X T2)+(C3 x T3)) Where:
Seismic Velocity/Depth Summary
NW SE
Depth (ft) Velocity (fps)
0 -3.5 1220
3.5 -30.9 3670
30.9 -ti### 6000
ti### -ti### 0
.. ti### -+ 0 +
SE NW
Depth (ft) Velocity (fps)
0 -1.8 1087
1.8 -31.6 3604
31.6 -ti### 6000
ti### -ti### 0
ti### -+ 0 +
I V = 1,087 -1,220 I SE NW I .,
10' 10' --I V = 3,604-3,670 I 20' 20' --
30' 30' -----
40' I V.:: 6000 I 40' -----
50'. 50' --
I SCHEMATIC CROSS SECTION l
W.O. 2929-A-SC
R1 = Velocity (fps) Ratio Factor (V2:V1)
D1 = Critical Distance
R2= Velocity (fps) Ratio Factor (V3:V2)
02= Critical Distance
C1 = Distance Correction Value (V3:V1)
R3= Velocity (fps) Ratio Factor (V4:V3)
D3= Critical Distance
C1 = Distance Correction Value (V4:V1)
C2= Distance Correction Value (V4:V2)
R40:: Velocity (fps) Ratio Factor (V5:V4)
D4= Critical Distance
C1 = Distance Correction Value (V5:V1)
C2 = · Distance Correction Value (V5:V2)
C3 = Distance Correction Value (V5:V3)
V1 = Seismic Velocity (fps) of 1st Layer
V2 = Seismic Velocity (fps) of 2nd Layer
V3 = Seismic Velocity (fps) of 3rd Layer
V4 = Seismic Velocity (fps) of 4th Layer
SL-4
NW-SE SE-NW
D 10 5
D2 113 120
D3
D4 -
V1 1220 1087
V2 3670 3604
V3 6000 6000
V4
vs
f.~iitilml~I~tt~~~;ti~t~~~ii~
T1 3.54 1.83
T2 27.37 29.80
T3 #11#11# #11#11#
T4 #11#11# '#1#1##
T1+T2 30.91 31.63
T1+T2+T3 #11#11# #11#11#
T1+T2+T3+T4 #11#11# '#1#1##
Plate No. C-4
------------------·-~I-
60.0
55.0
50.0
. I
V3 > 6,000fps -assumed 1
,_
-
45.0 .
/
/
/
40.0 ,
--., ... , ·" --........ --u 35.0 G)
ti)
::!!!
-~ :i:; ..... ------G)
E 30.0
i=
-a; > 25.0 I! I-
20.0
15.0
10.0 ~ , ~
~ ___ , ,, " 7
5.0 , ., ,
/Al1
/" V1 II I . 0.0
0 10
NW
~ ~
Traverse Date: 9/7/00
Orientation: N 56 W
~ . ...... ..,, . -
----. n -~
1.163fps
20
-
. S.eismic Traverse
:
--n ----· .w --.__. --,, . -I""'---,,, n ---.,. <I L,.-~-·----~ n ---'" -.... 1 l ,f•
I -. . -i
I I -LI .o --~ __,_ -_1 :_ . -I .O -.. I ... --., n \ I· I
I
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\ I
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I V2 = 3.311fps 1 I V2 = 4,040fps I
T
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30 40 50 60 70 80
Distance to Geophone (te,t)
Traverse No.: SL-4
.1 V3 > 6,000fps -assumed --·-
.
' '\--
\:'
" ------~ --. .. . o --., 1 --... -_,..
.£1 .4
I· I " <I --......:.
90
a·.::
I I l I 1---~~-----
.c :.;
-'·
---I I I" ' ,__ _.,. ~
~ ~~~10 --
I I ~ -.
/ -.
1.064fps : y ,·
V1 I
100 110 120
~ ~
SE
W.O. 2929-A-SC
Plate No. C-4a
.•, .. ,•
-,, . '~:,
''-~~:·_\ ~t'
,.', ._.· ) ,,
.;,:. _., ,-, '' ;, ..
" ,., .~_' .
·:-::.:,,, ',_,_
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. •.··· '·· ~ ·,
.... ,.
·1,,,·/,
' ; »•• ~ . ,,
,,:,
. ;_, ;., .. ,
._:·.?
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',• -,
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.· . ...-
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.-~ '-:.· ' ·,; ' l-. : ·-~---
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. ·'' '·.1·:_,i
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GENERAL EARTHWORK AND GRADING "GUIDELINES
General
These guidelines present general procedures and requirements for earthwork and grading
as shown on the approved grading plans, including preparation of areas to filled,
placement of fill, installation of subdrains and excavations. The recommendations
contained in the geotechnical report are part of the earthwork and grading guidelines and
Would supersede the provisions contained hereafter in the case of conflict. Evaluations
performed by the . consultant during the course of grading may result in new
recommendations which could supersede these· guidelines or the recommendations
contained in the geotechnical report.
The contractor is responsible. for the satisfactory completion of all earthwork in accordance
with provisions of the project plans and specifications. The project soil engineer and
engineering geolog_ist {geotechnical consultant) or their representatives should provide
observation and testing services, and geotectmical consultation during the duration of the
project.
EARTHWORK OBSERVATIONS AND TESTING
Geotechnlcal Consultant
Prior to the commencement of grading, a qualified geotechnical consultant (soil engine·er
and engineering geologist) should be employed for the purpose of observing earthwork
-· procedures and testing the fills for conformance with the recommendations of the
geotechnical report, the approved grading plans, and applicable grading codes and
ordinances.
The geotechnical consultant should provide testing and observation so that determination
may be made that the work is being. accomplished as specified. It is the responsibility of
the contractor to assist the consultants and keep them apprised of anticipated work
schedules and changes, so that they may schedule their personnel accordingly.
All clean-outs, prepared ground to receive fill, key excavations, and subdrains should be
-observed and documented by the project engineering geologist and/or soil engineer prior
to placing and fill. It is the contractors's responsibility to notify the engineering geologist
and soil engineer when such areas are ready for observation.
Laboratory and Field Tests
· Maximum dry density tests to determine the degree of compaction should be performed
in accordance with American Standard Testing Materials test method ASTM designation
D-1557-78. Random field compaction tests should be performed in accordance with test
_ method ASTM designation D-1556-82, D-2937 or D-2922 and D-3017, at intervals of
approximately 2 feet of fill height or every 100 cubic yards of fill placed. These criteria
GeoSoils, lne.
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would vary depending on the soil conditions and the size of the project. The location and
frequency of testing ·would be at the discretion of the geotechnical consultant.
Contractor-s Responsibility
All clearing, site preparation, and earthwork performed on the project should be conducted
by the contractor, with observation by geotechnical consultants and staged approval by
the governing agencies, as applicable. It is the contractor's responsibility to prepare the
ground surface to receive the fill, to the satisfaction of the soil engineer, and to place,
spread, moisture condition, mix and compact the fill in accordance with the
recommendations of the soil engineer. The contractor should also remove all major non-
earth material considered unsatisfactory by the soil engineer.
It is the sole responsibility of the contractor to provide adequate equipment and methods
to accomplish the earthwork in accordance with applicable grading guidelines, codes or
agency ordinances, and approved grading plans. · Sufficient watering apparatus and
compaction equipment should be provided by the contractor with due consideration for
the fill material, rate of placement, and climatic conditions. If, in the opinion of the
geotechnical consultant, unsatisfactory conditions such as questionable weather,
exces~ive oversized rock, or deleterious material, insufficient support equipment, etc., are
resulting in a quality of work that is not acceptable, the consultant will inform the
contractor, and the contractor is expected to rectify the conditions, and if necessary, stop
work until conditions are satisfactory.
During construction, the contractor shall properly grade all surfaces to maintain good
drainage and prevent ponding of water. The contractor shall take remedial measures to
--control surface water and to prevent erosion of graded areas until such time as permanent
drainage and erosion control measures have been installed.
SITE PREPARATION
All major vegetation, including brush, trees, thick grasses, organic debris, and other
deleterious material should be removed and disposed of off-site. These removals must be
concluded prior to placing fill. Existing fill, soil, alluvium, colluvium, or rock materials
determined by the soil engineer or engineering geologist as being unsuitable in-place
should be removed prior to fill placement. Depending upon the soil conditions, these
materials may be reused as compacted fills. Any materials incorporated as part of the
compacted fills should be approved by the soil engineer.
Any underground structures such as cesspools, cisterns, mining shafts, tunnels, septic
tanks, wells, pipelines, or other structures not located prior to grading are to be removed
or tr~ated in a manner recommended by the soil engineer. Soft, dry, spongy, highly
fractured, or otherwise unsuitable ground extending to such a. depth that surface
processing cannot adequately improve the condition should be overexcavated down to
Mr. David Bentley
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Appendix D
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firm ground and approved by the soil engineer before compaction and filling operations
continue. Overexcavated and processed soils which have been properly mixed and
moisture conditioned should be re-compacted to the minimum relative compaction as
specified in these guidelines.
Existing ground which is determined to be satisfactory for support of the fills should be
scarified to a minimum depth of 6 inches or as directed by the soil engineer. After the
scarified ground is brought to optimum moisture content or greater and mixed, the
materials should be compacted as specified herein. If the scarified zone is grater that 6
inches in depth, it may be necessary to remove the excess and place the material in lifts
· restricted to about 6 inches in compacted thickness.
Existing ground which is not satisfactory to support compacted fill should be
overexcavated as required in the geotechnical report or by the on-site soils engineer
and/or engineering geologist. Scarification, disc harrowing, or other acceptable form of
mixing should continue until the soils are broken down and free of large iumps or clods,
until the working surface is reasonably uniform and free from ruts, hollow, hummocks, or
other uneven features which would inhibit compaction as described previously.
Where fills are to be placed on ground with slopes steeper than 5:1 (horizontal to vertical),
the ground should be stepped or benched. The lowest bench, which will act as a key,
· should be a minimum bf 15 feet wide and should be at least 2 feet deep into firm material,
and approved by the soil engineer and/or engineering geologist. In fill over cut slope
conditions, the recommended minimum width of the lowest bench or key is also 15 feet
with the key founded on firm material, as designated by the Geotechnical Consultant. As
a general rule, unless specifically recommended otherwise by the Soil Engineer, the
minimum width of fill keys should be approximately equal to ½ the height of the slope.
Standard benching is generally 4 feet (minimum) vertically, exposing firm, acceptable
material. Benching may be used to remove unsuitable materials, although it is understood
that the vertical height of the bench may exceed 4 feet. Pre-stripping may be considered
for unsuitable materials in excess of 4 feet in thickness.
All areas to receive fill, including processed areas, removal areas, and the toe of fill
. benches should be observed and approved by the soil engineer and/or engineering
geologist prior to placement of fill. Fills may then be properly placed and compacted until
design grades (elevations) are attained.·
COMPACTED FILLS
Any earth materials imported or excavated on the property may be utilized in the fill
provided that each material has been determined to be suitable by the soil engineer.
These materials should be free of roots, tree branches, other organic matter or other
deleterious materials. All unsuitable materials should be removed from the fill as directed
Mr. David Bentley
File: e:\wp7\2900\2929a.lge
GeoS-,ils,. __ Ine.
Appendix D
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by the soil engineer. Soils of poor gradation, undesirable expansion potential, or
substandard strength characteristics may be designated by the consultant as unsuitable
and may require blending with other soils to serve as a satisfactory fill material.
Fill materials derived from benching operations should be dispersed throughout the fill
area and blended with other bedrock derived material. Benching operations should not
result in the benched material being placed only within a single equipment width away
from the fill/bedrock contact.
Oversized materials defined as rock or other irreducible. materials with a maximum
dimension greater than 12 inches should not be buried or placed in fills unless the location
of materials and disposal methods are specifically" approved by the soil engineer.
Oversized material should be taken off-site or placed in accordance with recommendations
of the soil engineer in areas designated as suitable for rock disposal. Oversized material
should not be placed within 1 o feet vertically of finish grade (elevation) or within 20 feet
horizontally of slope faces.
To facilitate future trenching, rock should not be placed within the range of foundation
· excavations, future utilities, or underground construction unless specifically approved by
the soil engineer and/or the developers repre~entative.
· If import material is required for grading, representative samples of the materials to be
utilized as compacted fill should be analyzed in the laboratory by the soil engineer to
determine its physical properties. If any material other than that previously tested is
encountered during grading, an appropriate analysis of this material should be conducted
by the soil engineer as soon as possible.
Approved fill material should be placed in areas prepared to receive fill in near horizontal
layers that when compacted should not exceed 6 inches in thickness. The soil engineer
may approve thick lifts if testing indicates the grading procedures are such that adequate
compaction is being achieved with lifts of greater thickness. Each layer should be spread
evenly and blended to attain uniformity of material and moisture suitable for compaction.
Fill layers at a moisture content less than optimum should be watered and mixed, and wet
fill layers should be aerated by scarification or should be blended with drier material.
Moisture condition, blending, and mixing of the fill layer should continue until the fill
materials have a uniform moisture content at or above optimum moisture.
After each layer has been evenly spread, moisture conditioned and mixed, it should be
uniformly compacted to a minimum of 90 percent of maximum density as determined by
ASTM test designation, D-1557-78, or as otherwise recommended by the soil engineer.
Compaction equipment should be adequately sized and should be specifically designed
for soil compaction or· of proven reliability to efficiently achieve the specified degree of
compaction.
Mr. David Bentley
File: e:\wp7\2900\2929a.lge
GeoSoils,. ·Ine.
Appendix D
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Where tests indicate that the density of any layer of fill, or portion thereof, is below the
required relative compaction, or improper moisture is in evidence, the particular layer or
portion shall be re-worked until the required density and/or moisture content has been
attained. No additional fill shall be placed in .an area until the last placed lift of fill has been
tested and found to meet the density and moisture requirements, and is approved by the
soil engineer.
Compaction of slopes should be accomplished by over-building a minimum of 3 feet
horizontally, and subsequently trimming back to the design slope configuration. Testing
shall be performed as the fill is elevated to evaluate compaction as the fill core is being
developed. Special efforts may be necessary to attain the specified compaction in the fill
slope zone. Final slope shaping shoulct be performed by trimming and removing loose
materials with appropriate equipment. A final determination of fill slope compaction should
be based on observation and/or testing of the finished slope face. Where compacted fill
slopes are designed steeper than 2:1 (horizontal to vertical), specific material types, a
higher minimum relative compaction, and special grading procedures, may be.
recommended. ·
If an alternative to over-building and cutting back the compacted fill slopes is selected,
then special effort should be made to achieve the required compaction in the outer 1 o feet
of each lift of fill by undertaking the following:
1. An extra piece of equipment consisting of a heavy short shanked sheepsfoot should
be used to roll (horizontal) parallel to the slopes continuously as·fill is placed. The
sheepsfoot roller should also be used to roll perpendicular to the slopes, and
extend out over the slope to provide adequate compaction to the face of the slope.
2.
3.
4.
5.
Loose fill should not be spilled out over the face of the slope as each lift is
compacted. Any loose fill spilled over a previously completed slope face should be
trimmed off or be subject to re-rolling. ·-
Field compaction tests will be made in the outer {horizontal) 2 to 8 feet of the slope
at appropriate vertical intervals, subsequent to compaction operations.
After completion of the slope, the slope face should be shaped with a small tractor
and then re-rolled with a sheepsfoot to achieve compaction to near the slope face.
Subsequent to testing to verify compaction, the slopes should be grid-rolled to
achieve compaction to the slope face. Final testing should be used to confirm
compaction after grid rolling.
Where testing indicates less than adequate compaction, the contractor will be
responsible to rip, water, mix and re-compact the slope material as necessary to
achieve compaction. Additional testing should be performed to verify compaction.
Mr. David Bentley
File: e:\wp7\2900\2929a.lge
Appendix D
Pages
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6. Erosion control and drainage devices should be designed by the project civil
engineer in compliance with ordinances of the controlling governmental agencies,
and/or in accordance with the recommendation of the soil engineer or engineering
geologist.
SUBDRAIN INSTALLATION
Subdrains should be installed in approved ground in accordance with the approximate
alignment and details indicated by the geotechnical consultant. Subdrain locations or
materials should not be changed or modified without approval of the geotechnical
consultant. The soil engineer and/or engineering geologist may recommend and direct
changes in subdrain line, grade and drain material in the field, pending exposed
conditions. The location of constructed subdrains should be recorded by the project civil
engineer.
EXCAVATIONS
Excavations and cut slopes should be examined during grading by the engineering
geologist. If directed by the engineering geologist, further excav~tions or overexcavation
· and re-filling of cut areas should be performed and/or remedial grading of cut slopes
should be performed. When fill over cut slopes are to be graded, unless otherwise
approved, the cut portion of the slope. should be observed by the engineering geologist
prior to placement of materials for construction of the fill portion of the slope.
The engineering geologist should observe all cut slopes and should be notified by the
contractor when cut slopes are started.
If, during the course of grading, unforeseen adverse or potential adverse geologic
conditions are encountered, the engineering geologist and soil engineer should
investigate, evaluate and make recommendations to treat these problems. The need for
cut slope buttressing or stabilizing should be based on in-grading evaluation by the
engineering ·geologist, whether anticipated or not.
Unless otherwise specified in soil and geological reports, no cut slopes should be
excavated higher or steeper than that allowed by the ordinances of controlling
governmental agencie!>. Additionally, short-term stability of temporary cut slopes is the
contractors responsibility.
Erosion control and drainage devices should be designed by the project civil engineer and
should be constructed in compliance with the ordinances of the controlling governmental
agencies, and/or in accordance with the recommendations of the soil engineer or
engineering geologist.
Mr. David Bentley
File: e:\wp7\2900\2929a.lge
GeoSoit,s_,: Ine.
Appendix D
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COMPLETION
Observation, testing and consultation by the geotechnical consultant should be conducted
during the grading operations in order to state an opinion that all cut and filled areas are
graded in accordance with the approved project specifications.
After comple~ion of grading and after the soil engineer and engineering geologist have
finished their observations of the work, final reports should be submitted subject to review
by the controlling governmental agencies. No further excavation or filling should be
undertaken without prior notification of the soil engineer and/or engineering geologist.
All finished cut and fill slopes should be protected from erosion and/or be planted in
accordance with the project specifications and/or as recommended by a landscape
architect. Such protection and/or.planning should be undertaken as soon as practical after
completion of grading. ·
JOB SAFETY
General
· At GeoSoils, Inc. (GSI) getting the job done safely is .of primary concern. The following is
the company's . safety considerations for use by all employees on multi-employer
construction sites. On ground personnel are at highest risk of injury and possible fatality
on grading and construction projects. GSI recognizes that construction activities will vary
on each site and that site safety is the prime responsibility of the contractor; however,
--everyone must be safety conscious and responsible at all times. To achieve our goal of
avoiding accidents, cooperation between the ~lient, the contractor and GSI personnel must
be maintained.
In an effort to minimize risks associated with geotechnical testing and observation, the
following precautions are to be implemented for the safety of field personnel on grading
and construction projects:
Safety Meetings: GSI field personnel are directed to attend contractors regularly
scheduled and documented safety meetings.
Safety Vests:
Safety Flags:
Mr. David Bentley
File: e:\wp7\2900~929a.lge
Safety vests are provided for and are to be worn by GSI personnel at
all times when they are working in the field.
Two safety flags are provided to GSI field technicians; one is to be
affixed to the vehicle when on site, the other is to be placed atop the
spoil pile on all test pits.
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Flashing Lights: · All vehicles stationary in the grading area shall use rotating or flashing
amber beacon, or strobe lights, on the vehicle during all field testing.
While operating a vehicle in the grading area, the emergency flasher
on the vehicle shall be activated.
In the event that the contractor's representative observes any of our personnel not
following the above, we request that it be brought to the attention of our office.
Test Pits Location, Orientation and Clearance
The technician is responsible for selecting test pit locations. A primary concern should be
the technicians's safety. Efforts will be made to coordinate locations with the grading
contractors authorized representative, and to select locations following or behind the
established traffic pattern, preferably outside of current traffic. The contractors authorized
represemative (dump man, operator, supervisor, grade checker, etc.) should direct
excavation of the pit and safety during the test period.· Of para~ount concern should be
the soil technicians safety and obtaining enough tests to represent the fill.
Test pits should be excavated so that the spoil pile is placed away form oncoming traffic,
whenever possible. The technician's vehicle is to be placed next to the test pit, opposite
the spoil pile. This necessitates the fill be maintained in a driveable condition.
-Alternatively, the contractor may wish to park a piece of equipment in front of the test
holes, particularly in small fill areas or those with limited access.
A zone of non-encroachment should be established for all test pits. No grading equipment
should enter -this zone during the testing procedure. The zone should extend
--approximately 50 feet outward from the center of the test pit. This zone is established for
safety and to avoid excessive ground vibration which typically decreased test results.
When taking slope tests the technician should park the vehicle directly above or below the
test location. If this is not possible, a prominent flag should be placed at the top of the
slope. The contractor's representative should effectively keep all equipment at a safe
operation distance (e.g. 50 feet) away from the slope during this testing.
The technician is directed to withdraw from the active portion of the fill as soon as possible
following testing. The technician's vehicle should be parked at the perimeter of the fill in
a highly visible location, well away·from the equipment traffic pattern.
The contractor should inform our personnel of all changes to haul roads, cut and fill areas
or other factors that may affect site access and site safety.
In the event that the techniciar1s.safety is jeopardized or compromised as a result of the
contractors failure to comply with any of the above, the technician is required, by company
policy; to immediately withdraw and notify his/her supervisor. The grading contractors
representative will eventually be contacted in an effort to effect a solution. However, in the
Mr. David Bentley
File: e:\wp7\2900\2929a.lge
GeoSoil,,. _Ine.
-.-,
Appendix D
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interim, no further testing will be performed until the situation is rectified. Any fill place can
be considered unacceptable and subject to reprocessing, recompaction or removal.
In the event that the soil technician does not comply with the above or other established
safety guidelines, we request that the contractor brings this to his/her attention and notify
this office. Effective communication and coordination between the contractors
representative and the soils technician is strongly encouraged in order to implement the
above safety plan.
Trench and Vertical Excavation
It is the contractor's responsibility to provide safe access into trenches where compaction
testing is needed.
Our personnel are directed not to enter any excavation or vertical cut which 1) is 5 feet or
deeper unless shored or laid back, 2) displays any evidence of instability, has any loose
rock or other debris which could fall into the trench, or 3) displays any other evidence of
any unsafe conditions regardless of depth.
All trench excavations or vertical cuts irt excess of 5 feet deep, which any person enters,
should be shored or laid back.
Trench access should be provided in accordance with CAL-OSHA and/or state and local
star,dards. Our personnel are directed not to enter any trench by being lowered or "riding
down" on the equipment.
·· If the contractor fails to provide safe access to trenches for compaction testing, our
company policy requires that the soil technician withdraw and notify his/her supervisor.
The contractors representative will eventually be contacted in an effort to effect a solution.
All backfill not tested due to safety concerns or other reasons could be subject lo
reprocessing and/or removal.
If GSI personnel become aware of anyone working beneath an unsafe trench wall or
vertical excavation, we have a legal obligation to put the contractor and owner/developer
on notice to immediately correct the situation. If corrective steps are not taken, GSI then .
has an obligation to notify CAL-OSHA and/or the proper authorities.
Mr. David Bentley
File: e:\wp7\2900\2929a.lge
GeoSoils, Jne.
Appendix D
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CANYON SU BO RAIN DETAIL
TYPE A
SEE Al TERNA TJVES
TYPE 8 ---------------~----~----------
' ' '
PROPOSED COMPACTED FILL ,.
, ' , ,
-"\. ', _ _.,-NATURAL GROUND =~ '\¥ , '4''¾ ',
SEE ALTERNATIVES
NOTE: ALTERNATIVES, LOCATION AND EXTENT OF-SUBDRAINS SHOULD BE DETERMINED
BY THE SOILS ENGINEER AND/OR ENGINEERING GEOLOGIST DURING GRAD ING.
PLATE EG-1
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CANYON SUBDRAIN ALTERNATE DETAILS
ALTERNATE t PERFORATED PIPE AND FILTER MATERIAL
A-1
· FILTER MATERIAL. .
SIEVE SIZE ·PERCENT PASSING
1 INCH , 100
·3/ 4 INCH 90-:-:100
3/8 INCH 40-100
NO. 4 25-40.
NO. 8 18-33
.NO. 30 :S-1s·
"NO. 50 .0-7.
NO. 200 0-3
. ALTERNATE ·2: PERFORATED PIPE, GRAVEL AND. FILTER FABRIC
~NIMUM OVERLAP . 5• MINIMUM OVER~~,
A-2
PER FORA TED PIPE: SEE ALTERNATE 1
GRAVEL: CLEAN 3/ 4 INCH ROO< OR APPROVED. SUBSTITUTE
FILTER FABRIC: MIRAFI 140 OR APPROVED SUBSTITUTE
PLATE EG-2
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DETAIL FOR FILL SLOPE TOEING OUT
ON FLAT ALLUVIA TED CANYON
TOE OF SLOPE AS SHOWN ON GRADING PLAN
ORIGINAL GROUND SURFACE TO BE
RESTORED WITH COMPACTED FILL -~~Gl:L_:-~~U~~
BACKcuA VARIES. FOR DEEP REMOVALS, ~$-,;:j r
BACKCUT ~~SHOULD BE MADE NO (,$-~ ·
STEEPER ·THA~:1 OR AS NECESSA~-~ ~,._ ANTICIPATED ALLUVIAL REMOYAL
FOR SAFETY .........._~,CONSIDERATIONS~
1
· ~ , DEPTH PER SOIL ENGaNEER. ~/"~ . / . -
'~)~ // .
~*-l~ovioEA 1:1 MIN1MuM PRoiEcTIONFROM r; OF
SLOPE AS SHOWN ON GRADING PLAN TO THE RECOMMENDED
REMOVAL DEPTH. SLOPE HEIGHT, SITE CONDITIONS AND/OR
LOCAL CONDITIONS COULD DICTATE FLATTER PROJECTIONS.
REMOVAL ADJACENT TO EXISTING FILL
ADJOINING CANYON FILL ·
---------------------
PROPOSED ADDITIONAL COMPACTED F.ILL
COMPACTED FILL LIMITS LINE;\
, TEMPORARY COMPACTED FILL ~ ---
. ).,FOR DRAINAGE ONLY ------
Qaf -.,J.(0, Oaf //clo7 (TO BE REMOVED)
!EXISTING COMPACTED FILL) ~', ~"' ~'\~Z§l/f~\ . k~~1111~ ' LEGEND
"7/IJ.YfP~' ~ TO BE REMOVED BEFORE Oaf ARTIFICIAL FILL
PLACING ADDITIONAL
COMPACTED FILL Oal ALLUVIUM
PLATE EG-3
-------------------
-u r )> -; n,
m G)
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TYPICAL STABILIZATION / BUTTRESS FILL DETAIL
15' TYPICAL
1-2· ---.. --; ~.,. >>> t I > >5!.Ft.
OUTLETS TO BE SPACED AT 100' MAXIMUM INTERVALS, AND SHALL EXTEND
1r BEYOND THE FACE OF SLOPE AT TIME OF. ROUGH GRADING COMPLETION.
I, •I BLANK ET FILL IF RECOMMENDED
BY THE SOIL ENGINEER
~'\\W/\°\lM------
.,, r .,.~ r 'ii: 4 1 ·
BUTTRESS OR SIDEHILL FILL I '-. 4 • DIAMETER NON-PERFORATED OUTLET PIPE
~. i ANO BACKDRAIN (SEE ALTERNATIVES) ~ ~
W'-'
3'MINIMUM KEY DEPTH
·-:·
-----. -. ----·----· -----\
TYPICAL STABILIZATION ·1 BUTTRESS SUBDRAIN DETAI.L
I+. MINIMUM r MINIMUM
PIPE
"1J r
)>
-I m
m
G>
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~ z
:I: .
N
i9 MINIMUM
·FILTER ~ATERIAL: MINIMUM OF FIVE FP/LINEAR Ft OF PIPF
OR FOUR Ffl/LINEAR Ft OF PIPE WHEN PLACED IN SQUARE
CUT TRENCH.
AL.JtRNATIVE IN LIEU OF FILTER MATERIAL: GRAVEL MAY B
ENCA~ED IN APPROVED FILTER FABRIC. FILTER FABRIC
SHALL BE MIRAFI 140 OR EQUIVALENT •. FILTER FABRIC
SHALL BE LAPPED A MINIMUM OF 1 r ON ALL JOINTS.
MINIMUM 4. DIAMETER PIPE: ABS-ASTM D-2751. SOR 35
OR ASTM D-1527 SCHEDULE 40 PVC-ASTM 0-3034,
SPR _35 OR ASTM D-1785 SCHEDULE 40 WI.Tlf A CRUSHING
STRE~GTH OF 1,000 POUNDS MINIMUM, AND A MINIMUM OF
8 UNIFORMLY SPACED PERFORATIONS PER FOOT OF PIPE
INSTALLED WITH PERFORATIONS OF BOTTOM OF PIPE.
PROVIDE CAf> AT UPSTREAM. ENO OF PIPE. SLOPE AT 2%
TO OUTLET PIPE. OUTLET PIPE TO BE CONNECTED TO
SUBDRAIN PIPE WITH TEE OR ELBOW.
NOTE:· 1. TRENCH FOR OUTLET PIPES TO BE BACKFILLED
WITH ON-SITE SOIL.
l, BACKDRAINS AND LATERAL DRAINS SHALL BE
LOCATED AT ELEVATION OF EVERY BENCH DRAIN.
FIRST DRAIN LOCATED AT ELEVATION JUST ABOVE
LOWER LOT GRADE. ADDITIONAL DRAINS MAY BE
REQUIRED AT THE DISCRETION OF THE SOILS
ENGINEER ANO/OR ENGINEERING GEOLOGIST.
FILTER MATERIAL SHALL BE OF
THE FOLLOWING SPECIFICATION
OR AN APPROVED EQUIVALENT:
SIEVE SIZE PERCENT PASSING.
1 INCH 100
3/4 INCH 90-100
3/8 INCH 40-100
NO. 4 25-40
NO.B 18-33
NO. 30 5-15
NO. 50 0-7
NO. 200 0-3
GRAVEL SHALL BE OF THE
FOLLOWING SPECIFICATION OR
AN APPROVED EQUIVALENT:
SIEVE SIZE PERCENT PASSING
1 1/2 INCH 100
NO. I+ 50
N0.200 8
SAND EQUIVALENT: MINIMUM OF 50
·-;:
-·---.. ---· -------. ----
FILL OVER NA TUR AL DETAIL
SIDEHILL FILL
TOE OF SLOPE AS SHOWN ON GRADING PLAN
PROVIDE A 1:1 MINIMUM PROJECTION FROM
DESIGN TOE OF SLOPE TO TOE OF KEY
AS SHOWN ON AS BUILT
NATURAL SLOPE TO
BE RESTORED WITH
""'[ J ~.MINIM~M
BENCH WIDTH MAY VARY
COMPACTED FILL
~
NOTE: 1. WHERE THE NATURAL, SLOPE APPROACHES OR EXCEEDS THE
-u r )>
-4 rn
rn
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1 MINIMUM KEY WIDTH DESIGN SLOPE RATIO. SPECIAL RECOMME,NDATl()NS WOULD BE
2°X 3• MINIMUM KEY DEPTH
2° MINIMUM IN BEDROCK OR
APPROVED MATERIAL.
PROVIDED BY THE SOILS ENGINEER.
2. THE NEED FOR ANO DISPOSITION OF DRAINS WOULD BE DETERMINED
BY THE SOILS ENGINEER BASED UPON EXPOSED CONDITIONS.
--------~----------
:FILL OVER CUT DETAIL
CUT/FILL CONTACT MAINTAIN MINIMUM 15° Fill SECTION FROM
1. AS SHOWN ON GRADING .PLAN BACKCUT TO FACE OF FINISH SLOPE --------------
2. AS SHOWN ON AS BUILT
COMPACTED FILL
H
ORIGINAL TOPOGRAPHY
BENCH WIDTH MAY VARY
-..11 I l r.::: ....
If~\ BEDROCK OR APPROVED MATERIAL
15° MINIMUM OR H/2
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)> -; m
m G)
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NOTE: THE CUT PORTION OF THE SLOPE SHOULD BE EXCAVATED ANO
EVALUATED BY THE SOILS ENGINEER ANO/OR ENGINEERING
GEOLOGIST PRIOR.TO CONSTRUCTING THE FILL PORTION.
-------------------
"1J r )>
-t m
m G)
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(X)
ST ABllJZA TION FILL, FOR UNSTABLE MATERIAL
EXPOSEo,·· 1N PORTION OF CUT .SLOPE
· NATURAL SLOPE
REMOVE: UNSTABLE MATEijlAL
~
~
t 15' MINIMUM ,~~ED EltllSHEP GRADE
OR APPROVED MATERIAL
MATERIAL
~'4!\;_,fi,WiUJ _JJ· MINIMUM TILTED BACK ·
. -., / ""'"~I IF RECOMMENDED BY THE SOILS ENGINEER ANO/OR ENGINEERING
t4 w~ ,.. ~ GEOLOGIST, THE REMAINING CUT PORTION OF THE SLOPE MAY
...,__ ___ ,__ ~/ REQUIRE REMOVAL ANO REPLACEMENT WITH COMPACTED FILL.
NOTE: 1. SUBDRAINS ARE NOT REQUIRED UNLESS SPECIFIED BY SOILS ENGINEER AND/OR ENGINEERING GEOLOGIST,
2. ·w· SHALL BE EQUIPMENT WIDTH (15'1 FOR SLOPE HEIGHTS LESS THAN 25 FEET. FOR SLOPES GREATER·
THAN 25 FEET ·w· SHALL BE DETERMINED BY THE PROJECT SOILS ENGINEER ANO /OR ENGINEERING
GEOLOGIST. AT NO TIME SHALL ·w· BE LESS THAN H/2.
---·---·-------------
-0 s;:
-I m
m G)
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SKIN FILL OF NATURAL GROUND
15• MINIMUM TO l}E MAINTAINED FROM
PROPOSED FINISH SLOPE FACE TO BACKCUT -
• ~};-,. L._ ,~ _,-. ~ i J' MINIMUM KEY DEPTH
1TH 7IV~M1//.\ V,b-JX»J., {Z>.J.. \ ,,,.A-' ---
/MINIMUM KEY WIDTH
ORIGINAL SLOPE
~ NOTE: 1. THE NEED AND DISPOSITION OF DRAINS WILL BE DETERMINED! BY THE SOILS ENGINEER AND/OR
ENGINEERING GEOLOGIST BASED ON FIELD CONDITIONS.
2. PAD OVEREXCAVATION ANO RECOMPACTION SHOULD BE PERFORMED IF DETERMINED TO BE
NECESSARY BY THE SOILS ENGINEER AND/OR ENGINEERING GEOLOGIST.
~--------~-~-------
-0
~ -I m
m G)
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0
DAYLIGH·T, CUT LOT .DETAIL·
RE.CONSTRUCT COMPACTED FILL SLOPE AT 2:1 OR FLATTER
(MAY INCREASE OR DECREAS.E· PAD AREAL
OVEREXCAVATE ANO RECOMPACT ---
REPLACEMENT FILL
AVOID ANO/OR CLEAN UP SPILLAGE OF
MATERIALS'ON THE NATURAL SLOPE
/
/
TYPICAL BE·NCHING
~
NOTE: 1. SUBORAIN ANO KEY WIDTH REQUIREMENTS WILL BE DETERMINED BASED ON EXPOSED SUBSURFACE
CONDITIONS AND THICKNESS OF OVERBURDEN.
2. PAD OVER EXCAVATION AND RECOMPACTION SHOULD BE PERFORMED IF DETERMINED NECESSARY BY
THE SOILS ENGINEER AND/OR THE ENGINEERING GEOLOGIST.
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TRANSITION LOT DETAIL
CUT LOT (MATERIAL TYPE TRANSITION)
-----
PAD GRADE
COMPACTED FILL
· TYPICAL BENCHING
CUT-FILL LOT (DAYLIGHT TRANSITION)
MUM
PAO GRADE
NOTE: * DEEPER OVEREXCAVATION MAY BE RECOMMENDED BY THE SOILS ENGINEER
ANO/OR ENGINEERING GEOLOGIST IN STEEP CUT-FILL TRANSITION AREAS.
-
PLATE EG-11'
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SETTLEMENT PLATE AND RISER DETAIL
2·x 2·x 114· STEEL PLATE
STANDARD 3/ 4 • PIPE NIPPLE WELDED TO TOP
OF PLATE.
3/4. X 5• GALYANIZED PIPE, STANDARD PIPE
TH READS TOP AND BOTTOM. EXTENSIONS
THREADED ON BOTH ENOS AND ADDED IN s·
INCREMENTS.
3 INCH SC.HEDULE 40 PVC PIPE SLEEVE, ADD IN
5• INCREMENTS. WITH GLU~ JOINTS.
FINAL GRADE
-· I r I
s·
/
/
I I . I • I . MAINTAIN 5• CLEARANCE OF HEAVY EQUIPMENT.
.....1-y,-.....L.J\-MECHANICALLY HAND COMPACT IN 2"VERTICAL
--s-+ -r'\r LIFTS OR ALTERNATIVE SUITABLE TO ANO
._ ____ ,... 11111..-__ .....,., ACCEPTED BY THE SOILS ENGINEER.
I 5• ,... s·
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· I MECHANICALLY HAND COMPACT THE INITIAL 5•
'
VERTICA~ WITHIN A 5• RADIUS OF PLATE BASE.
' ' ' ·'
:•: •• • •• : .·; .:•. • • •. •• •• • • •• BOTTOM OF CLEANOUT .......... ····· ...... .
PROVIDE A MINIMUM 1· BEDDING O.F COMPACTED SANO
NOTE:
1. LOCATIONS OF SETTLEMENT PLATES SHOULD BE CLEARLY MARKED AND READILY
VISIBLE (RED FLAGGED) TO EQUIPMENT OPERATORS.
2. CONTRACTOR SHOU LO MAINTAIN CLEARANCE OF A 5' RADIUS OF PLATE BASE ANO
WITHIN 5' (VERTICAL! FOR HEAVY EQUIPMENT. FILL WITHIN CLEARANCE AREA SHOULD
BE HANO COMPACTED .TO PROJECT SPECIFICATIONS OR COMPACTED BY ALTERNATIVE
APPROVED BY THE SOILS ENGINEER.
3. AFTER 5• (VERTICAL) OF FILL IS IN PLACE, CONTRACTOR SHOU LO MAINTAIN A 5• RADIUS
EQUIPMENT CLEARANCE FROM RISER.
4. PLACE ANO MECHANICALLY HAND COMPACT INITIAL 2· OF FILL PRIOR TO ESTABLISHING
THE INITIAL READING.
5. IN THE EVENT OF DAMAGE TO THE SETTLEMENT PLATE OR EXTENSION RESULTING
FROM EQUIPMENT OPERATING WIT.HIN THE SPECIFIED CLEARANCE AREA. CONTRACTOR
SHOULD IMMEDIATELY NOTIFY THE SOILS ENGINEER AND SHOULD BE RESPONSIBLE
FOR RESTORING THE SETTLEMENT PLATES TO WORKING ORDER. .
6. AN ALTERNATE DESIGN AND METHOD OF INSTALLATION MAY BE PROVIDED AT THE
DISCRETION OF THE SOILS ENGINEER.
PLATE EG-14
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TYPICAL SURFACE SETTLEMENT MONUMENT
FINISH GRADE ----:.:..:...:::::.~-------------------------------
'.
-----I-3/s· DIAMgTER X s· LENGTH
CARRIAGE BOLT OR EQUIVALENT
• DIAMETER X 3 1/2" LENGTH HOLE
....._-'-CONCRETE BACKFILL
PLATE EG-15
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TEST PIT SAFETY DIAGRAM
SIDE: VIEW
( NOT TO SCALE )
TOP VIEW
---~ r'lllf-------------='00::..:.f.:EE:.:.T ________ --.J~r
-50 FEET -
SPOIL
-P1LE
~ I ...
Hi u..
0 1ft
t-FLAG ' / ~
APPROXJMA TE CENTER ~
CF TEST PIT ~
1'
{ .NOT TO SCALE )
SO FEET -
PLATE EG-16
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OVERSIZE ROCK DISPOSAL
VIEW NORMAL TO SLOPE FACE
PROPOSED FINISH GRADE
<:::,::) c,::, 00 00 ,..,
1~1MU~~ (Bl 00 oO 20' MINIMUM
D (GI
00 c:::ic:::a QQ co
oO a:xF)
ViEW PARALLEL TO SLOPE FACE
.PROPOSED FINISH GRADE
1 O' MINIM UM (El
~
· 15' MINIMUM 3' MINIMUM
~~==:::ic=:IQIOIC~ ~ ~
15' MINIMUM
~
BEDROCK OR APPROVED MATERIAL
NOTE: (A) ONE EQUIPMENT WIDTH OR A MINIMUM OF 15 FEET.
(B) HEIGHT AND WIDTH MAY VARY DEPEND.ING ON ROCK SIZE AND TYPE OF
EQUIPMENT. LENGTH OF WINDROW SHALL BE NO GREATER THAN 100' MAXIMUM.
(C) IF APPROVED BY THE SOILS ENGINEER ANO/OR ENGINEERING GEOLOGIST,
WINDROWS MAY BE PLACED DIRECTLY ON COMPETENT MATERIAL OR BEDROCK PROVIDED ADEQUATE SPACE IS AVAILABLE FOR COMPACTION.
(Ol ORIENTATION OF WINDROWS MAY VARY BUT SHOULD BE AS RECOMMENDED BY
THE SOILS ENGINEER AND/OR ENGINEERING GEOLOGIST. STAGGERING OF
WINDROWS IS NOT NECESSARY UNLESS RECOMMENDED.
(El CLEAR AREA FOR UTILITY TRENCHES, FOUNDATIONS ANO SWIMMING POOLS.
(Fl ALL FILL OVER AND AROUND ROCK WINDROW SHALL BE COMPACTED TO 90%
RELATIVE COMPACTION OR AS RE.COMMENDED. .
(G) AFTER FILL BETWEEN WINDROWS IS PLACED AND COMPACTED WITH THE LIFT OF
FILL COVERING WINDROW, WINDROW SHOU LO BE PROOF ROLLED WITH A
D-9 DOZER OR EQUIVALENT.
VIEWS ARE DIAGRAMMATIC ONLY. ROCK SHOULD NOT TOUCH
ANO VOIDS SHOULD 8f COMPLETELY FILLED IN. PLATE RD-1
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ROCK DISPOSAL PITS
VIEWS ARE DIAGRAMMATIC ONLY. ROCK SHOUL.0 NOT TOUCH
ANO VOIDS SHOULD BE COMPLE1'ELY FILLED IN.
FILL LIFTS COMPACTED OYER
ROCK AFTER EMBEOMENT ,-------------• I
I .---1
~ COMPACTED Fl LL
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GRANULAR MATERIAL
------,
SIZE OF EXCAVATION TO BE
COMMENSURATE WITH ROCK SIZE
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ROCK DISPOSAL LAYERS
GRANULAR soil ro FILL vo10s. ~ . FcoMPACTED FILL
OENSIFJED BY FLOODING -;;--------..._
LAYER ONE ROCK HIGH { lO~D\
..... . ---...... ____________ _
PROFILE ALONG LA YER
FILL SLOPE
ICLEAR ZONE 20'.MINIMU_M
LAYER ONE ROCK. HIGH
PLATE RD-2
/
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\ ! ' .~.-,;.
~OS ANGELES CO.
RIVERSIDE CO.
ORANGE.CO.
SAN DIEGO co.
PRELIMINARY
" GEOTECHNICAL MAP · Plate 1 '"------------------------, ir
' WO. 2929-A-SC DATE 10/00 , _SCALE _f'_=.100'
All locations Are Approximate
LEGEND
,. . '' . ,
Tsa S31)tiago formation
··•. -l
K.gr/Jsp
/ . L App,;ximate locati~n of'g~olo~i~ cci~tact . ~----~--r __,,, _,
·• Gra~itic bedrock / Santiago Peak. volcanics
, ,, ·• ". -... ,' ,,
I ;' SL-4 Seismic lines
" Test pits
t i~" ;' -.
\,.-\ _., -
..
'
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i }
)
I
.
.
z
-_--,,
d'
'·;.-'
' _-' LOT•#,. . y> ··· •. ",-. ,, -:. ,'
, .. ·, ..
"·.,:'I;, i, . ,. ,,
< :-,: ·t>'..,'° '\ ,, ..
' .. ,.:·-. ,;
:,< ,,_-,-.,-.'..:-!. ·:-'/.:,·, ::,·~o ·.
, --,'.;::4.,::i;\i-.-.-· -
.. >\ . ' ) :s. . ... · · .... · · .....
.. ·.·.
·-· 6 . • c:. -"
. ·· ... · ..•• 7. . "/ ·.
.. 8 .··
. 9 . .
10
11
.
12 ..
i 13 ·.
14 .
15
16 _··
-17
18 . .·
19 ... . .
20 ••• ••
: r,.,;· 21', •
. . ..·· 22 . .
. 23 ..'..:cc
> 24,
. · .. 25} . ..
•'26 .. • ':·
-.
.·.· 27 • · ·. .-'' ' : __ ,"'·.··:
'":, :.-· ' ··: .. · 28 ,
' 29 ._.:
30 · .. ·
-
y -1-··· .·
GROSS . .NET
ACRES. ACRES
5.68 I 4.0
'0.3s 0.23 .·.
0.34 .· .·. 0.27
0.57 ... ' 0.33
0.85 0.25
0.51 ' ·~ 0.28
0.47 :·. ·. 0.29
0.33 0.29
0.71 0.29
0.60 .. 0.27
I. 11 . 0.28
l.22 0.27
0.23 . .
0.28 0.24
0.23 ' 0.20
_.,....
0.26 .
' -
0.24 . .
..
0.21-~ 0.22 .
-... • 0.31 0.23
.
0.45 0.24
• 0.46 · 0.22
.
1.00 . r· .. 0.22 ·.:· ........ , .
..
1.00 .. I• 0.23 .
o.s,2,·.·.· .. · .... 0.15
.
0.59 , .. · 0.29
.. ..
0.48 ' .. _· .. 0.24· · ·. -~ ,
. 0.26 . 0.45 .·· . ..
l.02 ·.•-· · • 0.24
L31 .· :·, ·_ :0.24
·0.90 0.24
-· ., C'_ . ;;;> ·. -')_:·:'~ .. _=··,
·,=· . .,
'
•
'
. '
GS
LOT# GROSS NET
ACRES ACRES
3 I . 0.98 0.27
...
32 0.98 0.28
33 0.28 0.22
· 34 0.20 .
. ·. .
.
35 0.34 0.23
.. ... .
· 36 . 0.35· 0.25 ..
'37 . .· 0.52 0.30
i i 38 0.74 0.24
39 0.27 I 0.16
.
' 40 . 0.21 .
. .
41 0.23 . .
42 0.26 .
43· 0.29 .
. · .
.
. 44 0.35 0.26 . .
45 0.41 0 25
. .
46 0.29 023
.·
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