HomeMy WebLinkAboutCT 02-17; SHELLEY PROPERTY; UPDATE GEOTECHNICAL INVESTIGATION; 2006-06-2611 IIIIIIIHOIOIIIHL
GEOCON
INC.ORPORAT-E.D . .
I GEOTECHNICAL CONSULTANTS
- (W)
I Project No. 06721-52-02
June 26, 2006 .
I RECEIVED
I
Fair Oaks Valley LLC OCT o i Post Office Bok 230638 . . . 0
Encinitas California 92023 AND DEVLLLJViE
I Attention Mr. Chuck Duvivier
ENGINEERING.
Subject; SHELLEY PROPERTY
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I.
0 CARLSBAD, CALIFORNIA
UPDATE GEOTECHNICAL INVESTIGATION
I .References: 1. Preliminary Geotechnical Investigation, Shelley Property, Carlsbad California,
0 prepared by Geocon Incorporated, dated November 28, 2001 (Project
No. 06721-12-01). 0 0
0 2. Grading Plans fir CT 02 17, Shelley Prqperty, (Fair Oaks Valley), prepared by
0 Pasco Engineering, Incorporated, dated March 20, 2006.
O
Gentlemen:
In accordance with your authorization we have updated our preliminary geotechnical investigation
I for the subject property. The accompanying report presents the results of our study and includes our
conclusions and recommendations regarding the geotechnical aspects of project development.
The presence of metamorphic rock exposed in outcrops and near-surface will impact development of
0 0 the property. However, the site is considered suitable for the proposed residential subdivision 0
- provided the recommendations of this report are followed. .. 0
O
Should you. have questions rcgarding this report, or if we may be of further service please contact the
undersigned at your convenience. 0 0 0 0
0 Very truly yours,
GEOCON INCORPORATED
AU 6 S /aad r, Shawn'Weedon
IM 17M CEG 1778 am"M GE 2714
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io
(6) Addressee
01. 0
0 6960 Flanders Drive • Son Diego, California 92121-2974 U Telephone (858) 558.6900 • Fax (858) 558-6159
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TABLE OF CONTENTS
I. PURPOSE AND SCOPE .................................................................................................................1
SITE AND PROJECT DESCRIPTION ...........................................................................................1
SOIL AND GEOLOGIC CONDITIONS.........................................................................................2
3.1 Topsoil (unmapped) .................................................................. . ............................................ 2
3.2 Colluvium (Qc) ......................................................................................................................2
3.3 Alluvium (Qal) ........................................................................................................................ 3
3.4 Santiago Formation (Ts) ........................................................................................................3
3.5 Santiago Peak Metavolcanics (Jsp) .......................................................................................... 3
ROCK RIPPABILITY......................................................................................................................3
GROUNDWATER/SEEPAGE ........................................................................................................ 4
GEOLOGIC HAZARDS .................................................................................................................... 4
6.1 Faulting and Seismicity ................................. .......................................................................... 4
6.2 Seismicity - Deterministic Analysis......................................................................................4
6.3 Liquefaction...........................................................................................................................5
6.4 Landsliding .................................... . ....................................................................................... s
CONCLUSIONS AND RECOMMENDATIONS ............................................................................. 6
7.1 General ................................................................................................................................... 6
7.2 Soil and Excavation Characteristics.......................................................................................6
7.3 Bulking and Shrinkage Factors...............................................................................................7
7.4 Subdrains.................................................................................................................................7
7.5 Seismic Design Criteria .........................................................................................................8
.7.6 Grading ..................................................................................................................................8
7.7 Slope Stability ....................................................................................................................... 10
7.8 Foundations ............ ........................................................................................................... ...10
7.9 Retaining Walls and Lateral Loads ....................................................................................... 14
7.10 Slope Maintenance...............................................................................................................15
7.11 Site Drainage ........................................................................................................................ 16
7.12 Grading and Foundation Plan Review .................................................................................16
LIMITATIONS AND UNIFORMITY OF CONDITIONS
MAPS AND ILLUSTRATIONS
Figure 1, Vicinity Map
Figure 2, Geologic Map (Map Pocket)
Figure 3, Typical Canyon Subdrain Detail
Figure 4, Subdrain Cut-Off Wall Detail
Figure 5, Subdrain Outlet Headwall Detail
Figure 6, Fill Slope Stability Analysis
Figure 7, Surficial Slope Stability Analysis
Figure 8, Retaining Wall Drainage Detail
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TABLE OF CONTENTS (Corftinued)
1 APPENDIX A
I FIELD INVESTIGATION
Table A-I, Seismic Traverses
Figures A-i - A-13, Logs of Trenches
I APPENDIX B
LABORATORY TESTING
Table B-I, Summary of Laboratory Maximum Dry Density and Optimum Moisture Content Test Results
1 Table B-il, Summary of Laboratory Direct Shear Test Results S
Table B-Ill, Summary of Laboratory Expansion Index Test Results
I APPENDIX I RECOMMENDED GRADING SPECIFICATIONS S
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UPDATE GEOTECHNICAL INVESTIGATION
1. PURPOSE AND SCOPE
This report presents the results - of a geotechnical investigation for an approximately 81-acre site
icicated in Carlsbad, California. Approximately 30 acres of the 81 acres will be 'developed for a
residential subdivision and the remaining area will be preserved for open space and as utility
easements. Our investigation focused on the residential area to be developed.
The purpose of the investigation was to evaluate surface and subsurface conditions on the property,
including rippability characteristics of the metamorphic rock underlying the site and, based on
conditions encountered, provide recommendations pertinent to th geotechnical aspects of developing
the proposed residential subdivision.
The scope of the investigation consisted of a site reconnaissance, review of published geologic
literature pertaining to the site, and conducting a field investigation; The field investigation was
conducted on May 3 and 8, 2001, and involved the collection of seismic refraction data on 4 lines,
geologic mapping, and the excavation of 13 exploratory backhoe trenches. A summary of the field
investigation, including logs of trenches and the results of the seismic refraction data is presented in
Appendix A. The approximate locations of seismic lines and the exploratory trenches are shown on
Figure 2 (Geologic Map, map pocket). -
The base map used for the geologic map was entitled Grading Plans for CT 02 17, Shelley Property
(Fair Oaks Valley), prepared by Pasco Engineering, Incorporated, dated March 20, 2006.
I Laboratory tests were performed on soil samples obtained from 'the exploratory excavations to
determine pertinent physical soil properties and are summarized in Appendix B.
2. SITE AND PROJECT DESCRIPTION
The property is located at the southern terminus of Camino Junipero, and consists of a roughly
rectangular shaped parcel of undeveloped land in the City of Carlsbad, California. The approximate
I :location of the property is shown on the Vicinity Map, Figure 1. The property is surrounded by
residential: development along the southern and western boundaries and undeveloped land on the
northern and eastern boundaries. A 100-foot-wide SDG&E power line easement transverses the
I northern portion of the site in an east/west direction.
I :Topographically the site can be characterized as a central drainage that trends northeast.to southwest.
Surface elevation ranges from a high of approximately 690 feet above Mean Sea Level (MSL) in the
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I 'northeastern corner of the property to a low of approximately 370 feet MSL along the southern
boundary. Metamorphic rock outcrops and boulders were observed across the majority of the site.
It is our understanding that area to be developed will be limited, to an area south of the SDG&E
easement, west of the main, central drainage,, and approximately 300 feet north of the southern
I . boundary. Review of the referenced grading plans indicates that a 51-lot residential subdivision is
currently planned for the prdperty. The grading plans indicate that maximum cut and fill depths of
approximately 25 feet and 30 feet, respectively, are proposed. Cut and fill slopes are planned at 2:1 I (horizontal: vertical) with maximum heights of roughly 40 feet and 35 feet, respectively;
The findings and recommendations presented herein are based upon a'site reconnaissance, review, of
the referenced plans, conditions encountered during our field investigation, and our understanding of
I the proposed development. If conditions and/or project details vary significantly from those described
above Geocon Incorporated should be consulted to provide additional recommendations and/or
analysis.) ',,' ,1 .
3. SOIL AND GEOLOGIC CONDITIONS
I Three surficial soil types and two geolOgic formations, were encountered during the field
investigation. The surficial soil consists of topsoil, colluvium,' and alluvium. The geologic formations
I Consist of Santiago Formation and Santiago Peak Metavolcanics. Each of the units is described below
in order of increasing age. The approximate locations of the unit boundaries are shown on the
Geologic Map, Figure 2.
I 3.1 Topsoil (unmapped)
Topsoil generally covers the site and generally consists of stiff, sandy clay with abundant cobble and
I boulders. The topsoil ranges between 1.5 to 4 feet thick. The topsoil is unsuitable in its present
condition for support of structural fill or foundations and will require remedial grading.
3.2 CollUvium (Oc)
I Colluvium exists along the canyon-side slopes and the base of natural slopes. These deposits are often
indistinguishable from alluvium and thick topsoil deposits, therefore, only the thicker, or potentially
thicker, areas have been mapped separately on the Geologic Map. In general, these deposits consist of I . poorly consolidated sandy clays to clayey sands and are potentially compressible. Development
within areas underlain by colluvium will require remedial grading as recommended in the concluding
sections of this report.
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3.3 Alluvium (Qal)
The alluvial deposits are typically composed of loose, porous, clayey sand to soft, sandy clay with
occasional boulders and cobbles, that have accumulated along canyon bottoms. These sediments are
generally poorly, consolidated and susceptible to settlement when subject to an increase in vertical
loads as might result from the placement of fill or structures. The alluvium' within the area of
development will require remedial grading.
3.4 Santiago Formation (Ts).
Sedimentary material associated with the Tertiary-age Santiago Formation was encountered in the
subsurface in Trenches T-8 and T-9. The material consisted of stiff, laminated, green clay. Numerous
randon-fly-oriented, localized shear zones were observed. It is our opinion that the observed evidence
of shearing is due to differential expansion and contraction of clay rather than slope deformation.
1 3.5 Santiago Peak Metavolcanics(Jsp)
Metavolcanic and metasedirnentary rock was exposed at the surface over the majority of the site and
I .was encountered all but one trench (T-8). The metavolcanic rock consists of slightly metamorphosed
andesitic rock, is very dense, and is resistant to weathering. In general the unit is highly jointed and
I 'fractured in the near surface and will yield dense angular cobbles and boulders up to approximately
3 feet in diam6ter. Joint and fracture. frequency will decrease with depth.
Grading and improvement construction will likely generate oversize materials (rocks greater than
12 inches). Due to the limited extent of proposed fill areas, rock placement will require planning and
coordination during grading. Oversize materials -should be placed in accordance with the rock
placement procedures presented in Appendix C of this report and the requirements of the City of
Carlsbad.
4. ROCK RIPPABILITY
Data for seismic. refraction linesand observations during exploratory trenching located in proposed
cut areas were evaluated to estimate rock rippability characteristics. The results of the investigation
indicate that only the upper-most portions of the cut where weathering and joint and fracture
frequencies are high can be excavated with heavy effort utilizing conventional heavy-duty grading
equipment. It is estimated that the depth to which ripping may be possible is no greater than 10 feet
and may be as shallow as 3 feet and blasting may be required.
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5. GROUNDWATER/SEEPAGE
Groundwater or water seepage was not observed in any of the 'exploratory trenches at the time of the
investigation. Groundwater is not expected to adversely, impact ,proposed project development.
However, the geologic units encountered on the site have permeability characteristics .and/or fracture
systems that could be susceptible under. certain conditions to groundwater seepage.: Seepage may
occur within fractured rock cut'slopes'That can create a nuisance to adjacent improvements.
6. GEOLOGIC HAZARDS
6.1 Faulting and Seismicity
A review of geologic literature indicates that there are no known active, potentially active, or inactiv
faults at the site. The Rosç Canyon Fault Zone, located approximately 8 miles northwest of the site, is
the closest known active fault. An active fault is defined by the California Geologic Survey (CGS), as
a fault showing evidence for activity roughly within the last 11,000 years. The CGS has included
portions of the Rose Canyon Fault Zone within a State of California Earthquake Fault Zone.
6.2 Seismicity - Deterministic Analysis
The computer program EQFAULT (Blake, 1998, updated 2004) was utilized to approximate the
distance of known faults to the site Within :a search radius of 50 miles from the site 13 known active
faults were identified. The results of the 'seismicity analyses indicate that the Rose Canyon Fault is
the dominant source of-potential ground motion at the site. Earthquakes on the Rose Canyon Fault
having a maximum magnitude of 7.2 are considered to be representative of the potential for seismië
ground shaking within the property. The estimated maximum ground acceleration expected at the site
was calculated to be approximately 0.35g, using the Sadigh et al. (1997), attenuation relation. The
earthquake events and site accelerations for seven faults considered most likely to subject the site to
ground shaking are presented on Table 6.2. The seismic risk at the site,is not considered significantly
greater than thatof the surrounding developments or the Carlsbad area in general.
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TABLE 6.2
DETERMINISTIC SITE PARAMETERS FOR SELECTED FAULTS
Fault Name
Distance
from Site
(miles) .
Estimated Maximum Earthquake Event
Maximum Earthquake (Mag) Peak Site Acceleration (g)
Rose Canyon 8 7.2 0.35
Newport-Inglewood 14 7.1 0.21
Coronado Bank 22 .7.6 0.16
Elsinore-Julian 24 7.1 0.11
Elsinore-Temecula 24 6.8 0.09
Palos Verdes 44 7.3 0.06
San Jacinto-Anza 46 7.2 0.05
It is our opinion that the site could be subjected to moderate to severe ground shaking in the event of
an earthquake along any of the faults listed in Table 6.2 or other faults in the southern California/
northern Baja California region. We do not consider the site to possess a greater risk than that of the
surrounding developments. While the listing of peak accelerations is useful for comparison of the
potential effects of fault activity in the region, other considerations are important in seismib design,
including the frequency and duration of motion and the soil conditions underlying the site. We
recommend that seismic design of the structures be performed in accordance with the Unifotm
Building Code (UBC) guidelines and/or those currently adopted by the City of Carlsbad.
6.3 . Liquefaction
Liquefaction typically occurs when a site is located in a zone with seismic activity, onsite soils are
cohesionless, groundwater is encountered within 50 feet of the surface, and soil densities are less than
about 70 percent of the maximum dry densities. If all four previous criteria are met, a seismic event
could result in a rapid 'pore water pressure increase from the earthquake-generated ground
accelerations. The potential for liquefaction occurring at the site is considered to be very low due to
the lack of a near surface permanent groundwater condition and, the dense nature of the proposed
compacted fill and formational materials. ,
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6.4 Landsliding
Landslides were not encountered during this or previous investigations and none are known to exist
on, the site.
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7. CONCLUSIONS AND RECOMMENDATIONS
7.1 General
7.1.1 No soil or geologic conditions were encountered that would preclude the de)velopment of
the property as planned, provided the recommendations of this report are followed.
7.1.2 The surficial soil deposits (topsoil, colluvium, and alluvium) are considered unsuitable for
the support of fill or structural loads in their present condition and will require removal and
compaction within the area of proposed development.
7.1.3 Excavations deeper than 3 to 10 feet into the volcanic rock for grading and/or below, grade
improvements should expect that blasting will be necessary as discussed below.
7.1.4 The metamorphic. rock has permeability 'characteristics and/or fracture systems that could
be susceptible under certain conditions to groundwater seepage The presence of perched
groundwater/seepage should be considered when planning remedial grading procedures
during the winter months.
7.2 ' 'Soil and Excavation Characteristics
7.2.1 The majority of the soils encountered in the field investigation are considered to have a
"very low" to "high" expansion potential (expansion index [El] of 130 or less) as defined
by the"Uniform Building Code (UBC) Table No. 18-I-B. If soil with an El greater than 130
is exposed near finish grade, modifications to the foundation and slab-on-grade
recommendations presented herein may be required.
7.2.2 The surficial soils can be excavated with light to moderate effort using conventional heavy
duty grading equipment. Heavy effort is expected for excavation of the uppermost portions
of the metamorphic rock. It is estimated that the proposed grading will encounter
nonrippable rock from 3 to 10 feet below the surface. In some areas the fresh nonrippable
I rocks are exposed at ground surface and will require surface blasting.
7.2.3 Undercutting utility trench locations should be considered during the grading phase of site
development. If dense rock is encountered during utility installation, linear blasting may be
necessary. Depending upon the blasting pattern and overburden thickness, the generation of
oversize rock could impact project development. Oversized rock should" be placed in
accordance with Recommended Grading Specifications (Appendix C) and the requirements
of the City of Carl sbad.'Since proposed fill areas and depths are relatively limited, oversize
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rock may require reduction to acceptable sizes or exportation from the property. Placement
of rock within proposed underground utility areas should not be permitted.
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7.3 Bulking and Shrinkage Factors
7.3.1 Estimates of embankment bulking and shrinkage factors are based on comparison of the
density of the material in situ and the density of the material when placed as fill. Bulking
and shrinkage factors roughly estimatedbecause large variations in natural soil density and
compacted fill density are, common. It is our opinion that the following bulking and
shrinkage factors should be used asa basis for roughly estimating how much the on-site
materials shrink or bulk. when they are excavated from their natural state and placed as
compacted fill. For. purposes of balancing the site, both maximum and minimum values of
bulking and shrinking factors should be used "in calculations to provide estimated
quantities. In addition, graded volumes should be monitored to forecast balance quantities.
TABLE 7.3
BULKING AND SHRINKAGE FACTORS
Soil Unit . Shrink/Bulk Factors :
Surficial Soils 5 to 10 percent shrink
Santiago Peak Metavolcanics 20 to 30 percent bulk
7.4 Subdrains
7.4.1 The geologic units encountered on the site have permeability characteristics and/or fracture
systems that could be susceptible under certain conditions to groundwater seepage. The use
of canyon subdrains will be necessary to mitigate the potential for adverse impacts
associated with seepage conditions. Figure 3 depicts 'a typical canyon subdrain detail.
7.4.2 The final 20-foot segment of the subdrains should consist of non-perforated drain pipe. At
the non-perforated/perforated interface, a seepage cutoff wall should be constructed on the
downslope side of the junction in accordance with Figure 4. Subdrains that discharge into a
natural drainage course or open space area should be provided with a permanent headwall
structure in accordance with Figure 5. .
7.4.3 The final grading plans should show the location of all proposed subdrains. Upon
completion of remedial excavations and subdrain installation, the project civil engin&er
should survey the drain locations and prepare an "as-built" map depicting the existing
conditions. .
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7.5 Seismic Design Criteria
7.5.1 Table 7.5 summarizes seismic design parameters obtained from the Uniform Building Code
(UBC) Table 16-J for Soil Profile Types, S, which is prevalent on this project. A summary
of the Soil Profile Type for each lot should be provided in the final report of grading. The
corresponding parameters listed in Table 7.5 should be used for seismic design. The nearest
Type A fault is the Elsinore-Julian, located approximately 24 miles from the site. The
nearest Type B fault is the Rose Canyon Fault, located approximately 8 miles from the site.
The values listed below are for the more dominant Rose Canyon Fault.
TABLE 7.5
SITE DESIGN CRITERIA
Parameter Value UBC Reference
Seismic Zone Factor 0.40 Table 16-I
Soil Profile Type Sc Table 16-J
Seismic Coefficient, Ca 0.40 Table 16-Q
Seismic Coefficient, C, 0.56 Table 16-R
Near-Sourc Factor, Na 1.0 Table16-S
Near Source Factor, N 1.0 Table 16-T
Seismic Source B Table 16-U
7.5.2 Conformance to the above criteria for seismic design does not constitute any kind of
guarantee or assurance that significant structural damage or ground failure will not occur if
a maximum level earthquake occurs. The primary goal of seismic design is to protect life
and not to avoid all damage, since such design may be economically prohibitive.
7.6 Grading
7.6.1 Grading should be performed in accordance with the attached Recommended Grading
Specifications (Appendix C) and the City of Carlsbad Grading Ordinance. Where the
recommendations of this section conflict with Appendix C, the recommendations of this
section take precedence. Earthwork should be observed and fill tested for proper
compaction by Geocon Incorporated.
7.6.2 Prior to commencing grading, a preconstructio'n conference should be held at the site with
the owner or developer, grading contractor, civil engineer, and geotechnical engineer in
attendance. Special soil handling requirements can be discussed at that time. -
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7.6.3 Site preparation should begin with the removal of deleterious material and vegetation. The
depth of removal should be such that material exposed in cut areas or soil to be used as fill
is relatively free of organic matter. Material generated during stripping and/or site
demolition should be exported from the site.
7.6.4 Potentially compressible surficial soil (topsoil, colluvium, and alluvium) within the area to
be developed should be removed to expose formational materials prior to placing fill and/or
structural loads. The depth of the removal will likely vary from 2 to 8 feet. In addition,
fractured claystone at the toe of the slope at Lot 1 and 2 should be removed to a minimum
width of 20 feet if encountered. The actual removal depths should be determined in the
field during the grading operations. Overly wet surficial materials, if encountered, will
require drying and/or mixing with drier soils to facilitate proper compaction.
7.6.5 The site should then be brought to final subgrade elevations with properly compacted fill.
In general, soil native to the site is suitable for re-use as fill if free from vegetation, debris
and other deleterious material Layers of fill placement should be no thicker than will allow
for adequate boiiding and compaction. Fill, including trench and wall backfill and scarified
ground surfaces; should be compacted to a dry density of at least 90 percent of maximum
dry density near to slightly above optimum moisture, content, as determined in accordance
with ASTM Test Procedure D 1557-02.
7.6.6 To reduce the potential for differential settlement, and to facilitate the excavation of
footings and utility trenches, cut lots that encounter hard metavolcanic rock and cut ill
transition pads, should be undercut a minimum of 3 feet and replaced with properly
compacted fill. The cut portion of the undercut should be sloped to the front or fill portion
of the lot at least 1 percent to allow future drainage of groundwater. Deeper undercutting of
street areas should be considered to facilitate the excavation of underground utilities where
the streets are located in cut areas composed of marginally- to non-rippable metavolcanic.
rock. If subsurface improvements or landscape zones are planned outside these areas,,
consideration should be given to undercutting these areas as well. Construction of
swimming pools at the rear of the building pads should expect hard rock conditions and
possible blasting.
7.6.7 Where practical, the upper 3 feet of building pads (cut or fill) and pavement areas should.
be composed of properly compacted "very low" to "low" expansive soils (EL of 50 or less).
Rock with a maximum dimension of 2 feet should be placed at least 2 feet below the
deepest utility and at least 3 feet below pad grade. Rock greater than 12 inches in
maximum dimension should not be placed within 3 feet of finish grade in building pad
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areas or within utility trench areas. Rock greater than 2 feet will require individual
I placement or breakage to 2-foot-minus for use in soil/rock fills.
7.7 Slope Stability
I 7.7.1 The results of the slope stability analyses indicate that the proposed fill slopes will have
calculated factors-of-safety in excess of 1.5 under static conditions for both deep-seated
and shallow sloughing conditions. The stability of the slopes was analyzed for fill slopes
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.. constructed at proposed 2:1 inclinations. Slope stability calculations for surficial stability
and deep-seated stability are presented on Figures 6 and 7.
7.7.2 ' Cut slopes excavated in the metavolcanic rock do not lend themselves to conventional
stability analysis. However, the results of our field investigation, and study of the fracture. I .
pattern, in relation with the proposed cut slopes, indicate that the proposed 2:1 cut slopes
should be stable with respect to, deep-seated failure and surficial sloughage up. to a
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. maximum height of 40 feet.
I 7.7.3 Cut slope' excavations should be observed during the grading operations by Geocon
Incorporated to check that geologic conditions 'do not differ significantly from those
expected. . I
7.7,4 The fill slopes should either be overbuilt a minimum of 3 feet-and cut back to final grade
I or, as a minimum, bakrolled with a sheepsfoot compactor at maximum 4-foot-high
intervals and track-walked by a D-8 bulldozer upon, completion to achieve the required
compaction.
7.7.5 Slopes should be planted, drained, and properly maintained to reduce erosion. Slope
I planting shoUld generally consist of drought tolerant plants having a variable root depth.
Slope watering should be kept to a minimum to just support the plant growth.
7.8 Foundations
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7.8.1 The following foundation recommendations are for one- to two-story residential structures
and are separated into categories dependent on the thickness and geometry of the
I . underlying fill and the expansion index of the prevailing subgrade soil of a particular
building' pad. The recommended minimum foundation and interior concrete slab design
criteria for each category is presented on Table 7.8.1. '
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TABLE 7.8.1
CONVENTIONAL FOUNDATION RECOMMENDATIONS BY CATEGORY
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Foundation Minimum
, Footing Depth Continuous Footing Minimum Interior Slab
Category (inches) Reinforcement Reinforcement
I 12 Two No. 4 bars; 6 x 6 - 10/10 welded wire mesh
one top, one bottom at slab mid-point
II 18 Four No. 4 bars; No. 3 bars at 24 inches on center,
two top, two bottom both directions at slab mid-point
III 24 Four No. 5 bars; No. 3 bars at 18 inches on center,
two top, two bottom both directions at slab midpoint
CATEGbRY CRITERIA
Category I: Lots with a fill thickness of less than 20 feet, expansion index less than or equal to
50, and a variation in fill thickness less than 10 feet.
Categoryll: Lots, with expansion index exceeding 50 but less than or equal to 90, fill thickness
of 20 feet or greater but less than 50 feet, or a variation in fill thickness greater
than or equal to 10 feet and-less than-20-feet.
Category III: Fill thickness is greater than or equal to 50 feet, variation in fill thickness is
greater than or equal to 20 feet, or expansion index exceeds 90 but is 130 or less.
Notes:
Footings should have a minimum width and depth of 12 inches.
Footing depth is measured from lowest adjacent subgrade.
Interior living area concrete slabs should be at least four inches thick for Categories I and II,
and 5 inches thick for Category III.
Interior concrete slabs should be underlain by at least 4 inches or 3 inches of clean sand or
crushed rock for a 4-inch-thick or 5-inch-thick slab, respectively.
Slabs expected to receive moisture-sensitive floor coverings or used to store moisture-
sensitive materials should be underlain by a vapor inhibitor covered with at least 2 inches of
the clean sand recommended in No. 4 above.
7.8.2 Foundations for Category I, II, or III may be designed for an allowable soil bearing
pressure of 2,000 pounds per square foot (psf) (dead plus live load). This bearing pressure
may be increased by one-third for transient loads such as wind or seismic forces.
7.8.3 The use of isolated footings which are located beyond the perimeter of the building and
support structural elements connected to the building is not recommended for Category.11I.
Where this condition cannot be avoided, the isolated footings should be connected to the
building foundation system with grade beams.'
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Project No. 06721-12-62 June 26, 2006
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I .7.8.4 For Foundation Category III, consideration should be given to using interior stiffening
beams and connecting isolated footings and/or increasing the slab thickness. In addition,
consideration should be given to connecting patio slabs that exceed 5 feet in width to the
I building foundation to reduce the potential for future separation to occur.
1 7.8.5 No special subgrade presaturation is deemed necessary prior to placing concrete; however,
the exposed foundation and slab subgrade soil should be moisture conditioned as necessary
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to maintain a moist condition, as would be expected in any such concrete placement.
7.8.6 Where buildings or other improvements are planned near the top of a slope steeper than 3:1
I . (horizontal: vertical), special foundations and/or design considerations are recommended
due to the tendency for lateral soil movement to occur.
I . For slopes less than 20 feet high, building footings should be deepened such that
the bottom outside edge of the footing is at least 7 feet horizontally from the face
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of the slope. .
For cut slopes in dense formational materials, or fill slopes inclined at 3:1
(horizontal: vertical) or flatter, the bottom outside edge of building footings should
I .be at least 7 feet horizontally inside the face of the slope, regardless of slope
height.
I . Swimming pools located within 7 feet of the top of cut or fill slopes are not
recommended. Where such a condition cannot be avoided, the portion of the
swimming pool wall within 7 feet of the slope face should be designed assuming
I . that the adjacent soil provides no lateral support. This recommendation applies to
fill slopes up to 30 feet in height, and cut slopes regardless of height. For
swimming pools located near the top of fill slopes greater than 30 feet in height,
additional recommendations may be required and Geocon Incorporated should be
I . contacted for a review of specific site conditions.
Although other improvements that are relatively rigid or brittle, such as concrete
flatwork or masonry walls, may experience some distress if located near the top of
a slope, it is generally not economical to mitigate this potential. It may be possible,
however, to incorporate design measures which would permit some lateral soil
I. movement without causing extensive distress. Geocon Incorporated should be
consulted for specific recommendations.
1 7.8.7 . As an alternative to the foundation recommendations for each category, consideration
should be given to the use of post-tensioned concrete slab and foundation systems for the
I support of the proposed structures. The pot-tensioned systems should be designed by a
structural engineer experienced in post-tensioned slab design and design criteria of the
Post-Tensioning Institute. (UBC Section 1816). Although this procedure was developed for
1 expansive soil, it can also be used to reduce the potential for foundation distress due to
differential fill settlement. The post-tensioned design should incorporate the geotechnical
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.
Project No. 06721-12-02 -12 - June 26, 2006
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parameters presented on Table 7.8.2 entitled Post-Tensioned Foundation System Design
Parameters for the particular Foundation Category designated. -
TABLE 7.8.2
POST-TENSIONED FOUNDATION SYSTEM DESIGN PARAMETERS
Post-Tensioning Institute (PTI) Foundation Category
Design Parameters
Thornthwaite Index -20 -20 -20
Clay Type—Montmorillonite Yes Yes Yes
3.. Clay Portion (Maximum) 30% 50% 70%
Depth to Constant Soil Suction 7.0 ft. TO ft. 7.0 ft.
Soil Suction 3.6 ft. 3.6 ft. 3.6 ft.
Moisture Velocity 0.7 in./mo. 0.7 in./mci. 0.7 in./mo.
1 7. Edge Lift Moisture Variation Distance 2.6 ft. 2.6 ft. 2.6 ft.
Edge Lift . 0.41 in. 0.78 in. 1.15 in.
Center Lift Moisture Variation Distance 5.3 ft. 5.3 ft. 5.3 ft.
Center Lift 2.12in. 3.21 in. 4.74 in.
7.8.8 UBC Chapter 18, Div. III, 1816 uses interior stiffener beams in its structural design
procedures. If the structural engineer proposes a post-tensioned foundation design method
other than UBC Chapter 18, Div. III, §1816, the following recommendations apply:'
* The deflection criteria presented in Table 7.5.2 are still applicable.
Interior stiffener beams be used for Foundation Categories 'II and III..
o The depth of the perimeter foundation should be at least 12 inches.
The perimeter footing depth should be at least 18 inches and 24 inches for
Foundation Categories II and III, respectively.
Geocob Incorporated should be consulted to provide additional design parameters as
required by the structural 'engineer.
7.8.9 Our experience indicates that, unless' reinforcing steel is placed at the bottom of perimeter
footings and interior stiffener beams, post-tensioned slabs are susceptible to excessive edge
lift, regardless of underlying soil conditions. Current PTI design procedures primarily
addres the potential for center lift of slabs but, because of the placement of the reinforcing
tendons in the top of the slab, the resulting stress eccentricity after tensioning reduces the
Project No. 06721-12-02 - 13 - June 26, 2006
ability of the system to mitigate edge lift. The structural engineer should design the
foundation system to reduce the potential of edge lift occurring for the proposed structures.
7.8.10 The recommendations of this report are intended to reduce the potential for cracking of•
slabs due to expansive soil (if present), differential settlement of deep fill; or fill of varying
thicknesses. However, even with the incorporation of the recommendations presented
herein, foundations, stucco walls, and slabs-on-grade placed on such conditions may still
exhibit some cracking due to soil movement and/or shrinkage. The occurrence of'concrete
shrinkage cracks is independent of the supporting soil characteristics. Their occurrence
may be reduced and/or controlled by limiting the slump of the concrete, proper concrete
placement and curing, and by the placement of crack control joints at periodic intervals, in
particular, where re-entrant slab corners occur.
7.9 Retaining Walls and-Lateral Loads
7.9.1 Retaining walls not restrained at the top and having a level backfill surface should be
designed for an active soil pressure equivalent to the pressure exerted by a fluid density of
35 pounds per cubic foot (pcf). Where the backfill will be inclined at no steeper than 2:1
(horizontal: vertical), an active soil pressure of 50 pcf should be used. These soil pressures
assume that the backfill materials within an area bounded by the wall and a 1:1 plane
extending upward from the base of the wall possess an expansion index of 50 or less. For
those lots with finish grade soil possess an expansion index greater than 50 and/or where
backfill materiais do not conform to the above criteria, Geocon Incorporated should be
consulted for additional recommendations.
7.9.2 Unrestrained walls are those that are allowed- to rotate more than 0.001H at the top of the
wall. Where walls are restrained from movement at the top, an additional uniform pressure
of 7H psf (where H equals the height of the retaining wall portion of the wall in feet)
should be added to the above active soil pressure. -
7.9.3 Retaining walls should be provided with a drainage system adequate to prevent the buildup
- of hydrostatic forces and should be waterproofed as required by the project architect. A
retaining wall drainage detail has been provided on Figure 6. The use of drainage openings
through the base of the wall (weep holes, etc.) is not recommended where the seepage
could be a nuisance or otherwise adversely impact the property adjacent to the base of the
wall. The above recommendations assume a properly compacted granular (expansion index
50 or less) backfill material with no hydrostatic forces or . imposed surcharge load. A
retaining wall drainage detail is presented on Figure 8. If conditions different than those
described are expected, or if specific drainage details are desired, Geocon Incorporated
should be contacted for additional recommendations.
Project No. 06721-12-02 -14 - June 26, 2006
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7.9.4 Wall foundations having a minimum depth and width of one foot may be designed for an
allowable soil bearing pressure of 2,000 psf, provided the soil within 3 feet below the base
of the wall has an expansion index of 90 or less. The proximity of the foundation to the top
of a slope steeper than 3:1 could impact the allowable soil bearing pressure. Therefore,
Geocon Incorporated should be consulted where such a condition is anticipated.
7.9.5 For resistance to lateral loads, an allowable passive earth pressure equivalent to a fluid
density of 300 pcf is recommended for footings or shear keys poured neat against properly
compacted granular fill soils or undisturbed natural soils. The allowable passive pressure
assumes a hOrizontal surface extending away from the wall at least 5 feet or three times the
height of the surface generating the passive pressure, whichever is greater. The upper
12 inches of material not protected by floor slabs or pavement should not be included in the
design for lateral resistance. An allowable friction coefficient of 0.4 may be used for
resistance to sliding between soil -and concrete. This friction coefficient may be combined
with the allowable passive earth pressure when determining resistance to lateral loads.
7.9.6 The recommendations preented above, are generally applicable to the design of rigid
concrete or masonry retaining walls having a maximum height of 8 feet. In the 6vent that
walls higher than 8 feet or other types of walls are planned, such as crib-type walls, Geocon
Incorporated should b'e consulted for additional recommendations.
7.10. Slope Maintenance
7.10.1 Slopes that are steeper than 3:1 (horizontal: vertical) may, under conditions which are both
difficult to prevent and predict, be susceptible to near surface (surficial) slope instability.
The instability is typically limited to the outer three feet of a portion of the slope and
usually does not directly impact the improvements on the pad areas above or below the
slope. The occurrence of surficial instability is more prevalent on fill slopes and is
generally preceded by a period of heavy rainfall,, excessive irrigation, or the migration of
subsurface seepage. The disturbance and/or loosening of the surficial soils, as might result
from root growth, soil expansion, or excavation for irrigation lines and slope planting, may
also be a significant contributing factor to surficial instability. It is, therefore, recom-
mended that, to the maximum extent practical: (a) disturbed/loosened surficial soils be
either removed or properly recompacted, (b) irrigation systems be periodically inspected
and ,maintained to eliminate leaks and excessive irrigation, and (c) surface drains on and
adjacent to slopes be periodically maintained to preclude ponding or erosion. It should be
noted that although 'the incorporation of the above recommendations should reduce the
potential for surficial slope instability, it will not eliminate the possibility, and, therefore, it
may be necessary to rebuild or repair a portion of the projects slopes in the future.
Project No. 06721-12-02 - - 15 - June 26, 2006
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7.11 Site Drainage
7.11.1 Adequate drainage is critical to reduce .the potential for differential soil movement, erosion,
and subsurface seepage. Under no circumstances should water be allowed to pond adjacent
to footings or behind retaining walls. The site should be graded and maintained such that
surface drainage is directed away from structures and the top of slopes into swales or other
controlled drainage devices. Roof and pavement drainage should be directed into conduits
that carry runoff away from the proposed structures.
7.11.2 Underground utilities should be leak free. Utility and irrigation lines should be checked
periodically for leaks for early detection of water infiltiation and detected leaks should be
repaired promptly. Detrimental soil-movement could occur if water is allowed to infiltrate
the soil for a prolonged period.
7.11.3 Landscaping planters adjacent to paved areas are not recommended due to the potential for
surface or irrigation water to infiltrate the pavement's §ubgrade and base course. Surface
drains to collect excess irrigation water and transmit it to drainage structures, or impervious
above-grade planter boxes should be used. In addition, where landscaping is planned
adjacent to the pavement, a cutoff wall should be provided along the edge of the pavement
and should extend at least 6 inches below the bottom of the base material.
7.11.4 The settlement of fill soil is typically triggered bya significant increase in soil moisture
content of the fill mass. Therefore, if proper surface drainage is provided and landscape
irrigation is established and maintained to just support the vegetation without overwatering;
the compacted fill mass may not experience the ultimate settlement potential. Alternatively,
an' undetected leaking watrline or poor drainage condition could cause localized
differential settlement that would not necessarily vary with the fill thickness
7.12 Grading and Foundation Plàfl Review
7.12.1' A review of the grading and fouidation plans should be performed prior to finaliiati on, to
check their compliance with the recommendations of this report and determine the need for
additional comments, recommendations, and/or analyses.
Project No. 06721-12-02 -16 - June 26, 2006
I
LIMITATIONS AND UNIFORMITY OFCONDITIONS
1. The recommendations of this report pertain 'only (o -the site investigated and are based upon I the assumption that the soil conditions do not deviate from those disclosed in the investigation.
If any, variations or undesirable conditions are encountered during construction or if the
I proposed construction will differ from that anticipated herein, Geocon Incorporated should be
notified so that supplemental recommendations can be given The evaluation or identification
I of the potential presence of hazardous or corrosive materials was not part of the scope of
services provided by Geocon Incorporated .
2 This report is issued with the understanding that it is the responsibility of the owner, or of his
representative, to ensure that the informati6n and recommendations contained herein are
I brought to the attention of the architect and engineer for the project and incorporated into the
plans and the necessary steps are taken to see that the contractor and subcontractors carry out
such recommendations in the field
I
3. The findings of this report are valid as of the present date. However, changes in the conditions
I of a property can occur with the passage of time whether they be due to natural processes or
the works of man on this or adjacent properties In,,addition changes in applicable or
I ' appropriate standards may occur, whether they resultfrom legislation or the broadening of
knowledge. Accordingly, the findings of this report may be invalidated wholly or partially by.
changes outside ourcontrol. Therefore, this report is subject to review and should not be relied
I upon after a period of three years. .
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Project No. 06721-52-'02 . . June 23, 2006
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SOURCE 2006 THOMAS BROTHERS MAP
- ' SAN DIEGO COUNTY, CALIFORNIA
. NI REPRODUCED WITH PERMISSION GRANTED BY THOMAS BROTHERS MAPS.
THIS MAP IS COPYRIGHT BY THOMAS BROS. MAPS. IT IS UNLAWFUL TO COPY NO SCALE OR REPRODUCE ALL OR ANY PART THEREOF. WHETHER FOR PERSONAL USE OR
RESALE, WITHOUT PERMISSION.
S . .
GEOCON '. .
I. INCORPORATED
GEOTECHNICAL CONSULTANTS -
- 6960 FLANDERS DRIVE SAN DIEGO, CALIFORNIA 92121 - 2974
I PHONE 858 558-6900 — FAX 858 558-6159 / -
AS RA
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SHELLEY PROPERTY - • - -
- • • CARLSBAb, CALIFORNIA
DATEo6_62OO6j
. PROECTNO. 0672152-02 FIG. 1
2'
,A.APPROVED
/ FILTER FABRIC
/ A 1" MAX. OPEN-GRADED
AGGREGATE 9 CUBIC FT/FT.
L I MINIMUM
-41
6" DIA. PERFORATED
SUBDRAIN PIPE
-. 5'MIN.
NOTES: . .
1.....SUBDRAIN PIPE SHOULD BE 6-INCH MINIMUM DIAMETER, PERFORATED, THICK WALLED SCHEDULE
40 PVC, SLOPED TO DRAIN AT 1 PERCENT MINIMUM AND CONNECTED TO STORM DRAIN SYSTEM OR
APPROVED OUTLET.
2.....WHERE DRAIN EXCEEDS 1000 FEET, PIPE DIAMETER SHOULD BE INCREASED TO 8 INCHES.
3.....FILTER FABRIC TO BE MIRAFI 140N OR EQUIVALENT.
TYPICAL CANYON SUBDRAIN DETAIL
GEOCON
0 INCORPORATED
GEOTECHNICAL CONSULTANTS
6960 FLANDERS DRIVE - SAN DIEGO, CALIFORNIA 92121- 2974
PHONE 858 558-6900 - FAX 858 558:6159
AS I RA . DSK/E0000
-7
X:/IDETJL/1SD/DWG.
SHELLEY PROPERTY
CARLSBAD, CALIFORNIA'
DATE 0626_2006PROJECT NO. 06721-52-02 FIG:3
I -6"MIN.
SUBDRAIN . . . . .
PIPE
CONCRETE i_. - - - - $ _
6 MIN
CUT-OFF WALL .. . . •. .
. ....
: 24"
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NO SCALE
CONCRETE _-..A.
CUT-OFF WALL . 6' MIN. (rYP)
SOLID SUBDRAIN PIPE
-
PERFORATED SUBDRAIN PIPE
J 6 MIN P)
NO SCALE
I TYPICAL SUBDRAIN CUT-OFF WALL DETAIL
. I
I GE000N (4400 I .INCORPORATED
GEOTECHNICAL CONSULTANTS
6960 FLANDERS DRIVE - SAN. DIEGO, CALIFORNIA 92121 - 2974
I PHONE 858 558-6900 - FAX 858 558-6159
AS IRA
- .
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SHELLEY PROPERTY
CARLSBAD, CALIFORNIA
DATE 06-26- 2006 PROJECT NO. 06721-52-02 1 FIG. 4
FRONT VIEW
I
24
NO SCALE
NOTE: HEADWALL SHOULD OUTLET INTO CONTROLLED SURFACE DRAINAGE
NO SCALE
TYPICAL SUBDRAIN OUTLET HEADWALL DETAIL
GEOCON
I INCORPORATED 4.00 -
GEOTECHNICAL CONSULTANTS
6960 FLANDERS DRIVE - SAN DIEGO, CALIFORNIA 92121-2974
PHONE 858 558-6900 - FAX 858 558-6159
AS/RA 1 DSk/G1YPD
XJR14TEMP/IAUTOCAD PLATE TEIJ'LATE/1DETAJL50HD
I
SHELLEY PROPERTY
CARLSBAD, CALIFORNIA
7 77 DATE 06-26-2006 PROJECT NO. 06721 -52-02 FIG.5
U
PROIW'T NO O671..1..fl1
ASSUMED CONDITIONS:
Slope Height H = 40 feet
Slope Inclination . 2:1 (Horizontal Vertical)
Total Unit Weight of Soil 'Yt =. 130 pounds per cubic foot
Angle of Internal Friction . = 28 degrees " Apparent Coheion C = 400 pounds per square foot
No Seepage Forces
ANALYSIS:
yco yH tai(b Equation (3-3), Reference 1
C
FS = Equation (3-2), Reference 1
yH.
yco = 6.9 , Calculated Using Eq. (3-3)
Ncf = 25 Determined Using Figure 10 Reference 2 t
FS = 1.9 Factor of Safety Calculated Using Eq. (3-2)
REFERENCES:
I
Janbu, N., Stability Analysis ofSlopes.with Dimensionless Parameters, Harvard Soil Mechanics,
Series No. 46, 1954.
Janbu,.N., Discussion of J. M. Bell, Dimensionless Parameters for Homogeneous Earth Slopes,
Journal of Soil Mechanics and Foundation Design, No. SM6, Nov'ember 1967.
SLOPE STABILITY ANALYSIS—FILL SLOPES
SHELLEY PROPERTY •
.
• CARLSBAD, CALIFORNIA
U
•• • •, FIGURE
i.
•
(I
I H
I PROTECT NO. 06721-12.01
ASSUMED CONDITIONS:
Slope Height . H = Infinite
Depth of Saturation Z = 3 1 feet
Slope Inclination . 2:1 (Horizontal :Vertical)
Slope Angle i = 26.6 degrees
Unit Weight of Water 'y = 62.4 pounds per cubic foot
Total Unit Weight of Soil Y, 130 pounds per cubic foot
Angle of Internal Friction. = 28 degrees
Apparent Cohesion .. . C = 400 pounds per square foot
Slope saturated to vertical depth Z below slope face.
Seepage forces parallel to sloe face
ANALYSIS: .
.
.
FS =
C+(y—y)Z Cos 2i tan Ø
=3.1
y,Z sin i cos i
REFERENCES:
Haefeli, R. The Stability of Slopes Acted Upon by Parallel Seepage Proc. Second International
Conference, SMFE, Rotterdam, 1948, 1, 57-62. .
Skempton, A. W., and F. A. Delory, Stability, of Natural Slopes in London Clay, Proc. Fourth
International Conference, SMFE, London, 1957, 2, 378-81.
SUIRFICIAL SLOPE STABILITY ANALYSIS
SHELLEY PROPERTY .
-. . CARLSBAD, CALIFORNIA
FIGURE 7
12- MIN. GROUND SURFACE
RETAINING WALL
3/4" CRUSHED
GRAVEL
H MIRAFI 14N
FILTER FABRIC
OR, EQUIVALENT
S. 2/3H
4" DIA. SHEDULE 40 PVC
PERFORATED PIPE
-
FOOTING 1"
7MIN.
SETBACK
NOTES:
1 ...... PREFABRICATED DRAINAGE PANELS, SUCH AS MIRADRAIN 7000 OR EQUIVALENT,
MAYBE USED IN LIEU OF PLACING GRAVEL TO HEIGHT OF 2/3 THE TOTAL WALL HEIGHT
2......DRAIN SHOULD BE UNIFORMLY SLOPED AND MUST LEAD TO A POSITIVE GRAVITY OUTLET
3......TEMPORARY EXCAVATION SLOPES SHOULD BE CONSTRUCTED AND/OR SHORED IN
ACCORDANCE WITH CAL-OSHA REGULATIONS I NO SCALE
RETAINING WALL DRAINAGE DETAIL
GE000N
Q INCORPORATED
GEOTECHNICAL CONSULTANTS
I
6960 FLANDERS DRIVE - SAN DIEGO, CALIFORNIA 92121- 2974
PHONE 858 558-6900 - FAX 858 558-6159
RA I SW DSK/GTYPO
X/RMTEMPA-AUTOCAD PLATE T&APLATEkDETAIURETWALL4
SHELLEY PROPERTY
CARLSBAD, CALIFORNIA
DATE 06-26-2006 IPR0JECTN0 06721-52-021 FIG.8
I
APPENDIX A
FIELD INVESTIGATION
The-field investigation was conducted on May 3 and 8, 2001, and consisted of collection of seismic
refraction data on 4 lines, geologic mapping, and the excavation of 13 exploratory backhoe trenches
Bulk soil samples were obtained from the material generated during exploratory trenching. The soils
encountered were examined, visually classified, and l6gged. Logs of the exploratory trenches are
presented as Figures A-i through A-13. The logs indicate the general material types encountered and
the depth at which samples were obtained. The results of the seismic refraction traverses are
presented below in Table A-I.
TABLE A-I
SEISMIC TRAVERSES
Seismic
Traverse
No
Average Velocity
(ft./sec.)
Average Depth
(ft.) Length of
Traverse
(ft) D3
Approximate
Maximum
Depth Explored
V1 V2 V3 D1 D2
SL-1 2,350 13,150 N/A 7 30+ N/A 100 30
SL-2 2,900 18,700 'N/A 3 30+ 'N/A 100 30
SL-3 3,250 17,250 N/A 9 30+ N/A 100 30
SL-4 J 1,600 8,300 N/A 4 30+ rN~A 100 30
V1 = Velocity in feet per second of first layer of materials
V2 = Second layer velocities
V3 = Third layer velocities
D1 = Depth in feet to base of first layer
D2 = Depth to base of second layer
Depth to base of third slayer
NOTE: '
For mass grading, materials with velocities of less than 4500 fps are generally rippable with a D9 Caterpillar
Tractor equipped with a single shank hydraulic ripper. Velocities of 4500 to 5500 fps indicate marginal ripping
and blasting. Velocities greater than 5500 fps generally require' pre-blasting. For trenching, materials with
velocities less than 3800 fps are generally rippable depending upon the degree of fracturing and the presence or
absence of boulders. Velocities between 3800 and 4300 fps generally indicate marginal ripping, and velocities
greater than 4300 fps generally indicate non-rippable conditions. The above velocities are based on a
Kohring 505.
The reported velocities represent average velocities over the length of each traverse, and should not generally
be used for subsurface interpretation greater than 100 feet from a traverse.
Project No. 06721-52-02 1 June 26, 2006
I PROJECT NO. 0672r-12-01
TRENCH T1 (.D I—
DEPTH SAMPLE 0 0 SOIL : '
FEET ELEV. (MSL.) 528 DATE COMPLETED 5/8/01 Lu
• EQUIPMENT JD410D W -' z co
MATERIAL DESCRIPTION
•
7-
.'
TOPSOMJCOLLUVIUM
Stiff, moist, reddish-brown, Sandy CLAY -
-2 - CL' -
Ti-i
0
-Contact varies 1.5 to 4 feet
ANTIAGO PEAK METAVOLCANICS
lightly weathered, dark green METAVOLCANIC
LROCK,joint N70W, 72N, and N60E90, excavates
o angular cobble size to 12 to 16 inches'
'TRENCH TERMINATED AT 4.FEET DUE TO
REFUSAL
0 '• 0
, S
I ' S
55
- Figure A-i, Log of Trench T 1 • ' • SHEL
I.
NOTE: THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE
DATE INDICATED. IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
I.
• S
-
... SAMPLING UNSUCCESSFUL LI ... STANDARD PENETRATION TEST M ... DRIVE SAMPLE (UNDISTURBED) SAMPLE SYMBOLS
DISTURBEDOR BAG SAMPLE ... CHUNK-SAMPLE .:. WATER TABLE OR SEEPAGE
PROJECT NO. 071-12-01 -
TRENCH T2
DEPTH SAMPLE SOIL
ELEV. (MSL.) 509 DATE COMPLETED 5/8/01 FEET
EQUIPMENT JD 410 D
Ci
MATERIAL DESCRIPTION -0 -
TOPSOIL - Medium dense, slightly moist, reddish-brown, - GC Clayey GRAVEL withSAND, rock is
i metamorphic, angular - 2
- T271
-
- SANTIAGO PEAK METAVOLCANICS
Slightly weathered, dark grayish-green, very strong
\ METAVOLCANIC ROCK. Refusal
REFUSAL ON ROCK AT 3.5 FEET
Figure A-2, Log of Trench T 2
. SHELl
I SAMPLE SYMBOLS ... SAMPLING UNSUCCESSFUL IJ ... STANDARDPENETRATION TEST ... DRIVE\SAMPLE (UNDISTURBED)
DISTURBED OR BAG SAMPLE ... CHUNK SAMPLE . . WATER TABLE OR SEEPAGE
I . NOTE: THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY APTHE SPECIFIC BORING OR TRENCH LOCATION AND AT THE
DATE INDICATED. IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
PROJECT NO. 06721-12-01 0
TRENCH T 3CD >-
DEPTH SOIL. SAMPLE
NO. ELEV. (MSL.) 424 DATE COMPLETED 5/8/01 FEET
0
EQUIPMENT JD 410 D
MATERIAL DESCRIPTION
:
CL TOPSOIL
Stiff, moist, red brown Silty CLAY
SANTIAGO PEAK METAVOLCANICS - Slightly weathered, dark grayih-green,
- METAMORPHIC ROCK, highly jointed N32E 90,
4 - N62E 70W, N15E 66W, N25W 60S, excavates to - cobble 6 inches max and gravel
___________
_
_
-_
TRENCH TERMINATED AT 5 FEET DUE TO
REFUSAL
0
- Figure A-3, Lou of Trench T 3 - -
- sHELl 1 rSAMPLE SYMBOLS E... SAMPLING UNSUCCESSFUL 10 ... STANDARD PENETRATION TEST ... DRIVE SAMPLE (UNDISTURBED)
1 DISTURBED OR BAG SAMPLE ... CHUNK SAMPLE ... WATER TABLE OR SEEPAGE
I NOTE: THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR T
R
E
N
C
H
L
O
C
A
T
I
O
N
A
N
D
A
T
T
H
E
DATE INDICATED. IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTH
E
R
L
O
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Figure A74, Log of Trench T 4
PROJECT NO. 06721-12-01
TRENCH T4
10 DEPTH
LD
SOtL
LW'
SAMPLEIN NO. ELEV. (MSL.) 448 DATE COMPLETED 5/8/01 wj FEET
EQUIPMENT JD41OD
MATERIAL DESCRIPTION -0
r/a, CL TOPSOHJCOLLUVIUM
- T4-1 'Firm, slightly moist, red-brown, Silty CLAY, with
angular metamorphic rock 2 inches max
• GC
- /4' Very dense, slightly mist, Clayey GRAVEL,
angular metamorphic rock to 2 inches (highly
• — - jointed, highly weathered metamorphic rock)
SANTIAGO. PEAK METAVOLCANICS
\ Moderately weathered, dark green, highly jointed
• METASEDIMENTARY? to 3 inches max, angular
TRENCH TERMINATED AT 4 FEET DUE TO
,REFUSAL
SAMPLE SYMBOLS ... SAMPLING UNSUCCESSFUL II ... TANDARD PENETRATION TEST U ... DRIVE-SAMPLE (UNDISTURBED)
... DISTURBED OR BAG SAMPLE ... CHUNK SAMPLE ... WATER TABLE OR SEEPAGE
I NOTE: THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE
DATE INDICATED. IT 'IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
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PROJECT NO. 06721-12-01
(pn W TRENCH T 5 :
DEPTH SOIL . '•'
IN SAMPLE
NO. z CLASS -
ELEV. (MSL.) 423 DATE COMPLETED 5/8/01 FEET H o (USCS) wH0
CD EQUIPMENT JD 410 D
MATERIAL DESCRIPTION
- 0
- ALLUVIUM
Stiff, moist, red-brown, fine Sandy CLAY with
silt
- 2
- T5-1 I '. CL
SANTIAGO PEAK METAVOLCANICS
- 6 - ' Highly weathered, highly jointed, dark
greenish-brown METAVOLCANIC ROCK,
- excavates to 3 inches max 'I
\.- Becomes fresh, unable to exdavate • . TRENCH TERMINATED AT 6 FEET DUE TO
--------
REFUSAL
Figure A-5. Lwof Trench T SML
SAMPLE SYMBOLS SAMPLING UNSUCCESSFUL II ... STANDARD PENETRATION TEST U ... DRIVE SAMPLE (UNDISTURBED)
DISTURBED OR BAG SAMPLE ... CHUNK SAMPLE ... WATER TABLE OR SEEPAGE
I
NOTE: THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE
DATE INDICATED. IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
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PROJECT NO. 06721-12-01 -
TRENCH T 6 z
DEPTH SOIL HI- H
IN
\FEET
SAMPLE
NO.
o = a Z CLASS
/
ELEV. (MSL.) 404 DATE COMPLETED 5/8/01 rtu
LL. wj a z
H (USCS) H LLI
EQUIPMENT JD 410 D
MATERIAL DESCRIPTION
0 :
• • 7, CL TOPSOIL
Stiff, moist, red-brown, Sandy CLAY - -
-2 -
SANTIAGO PEAK METAVOLCANICS
- L- Hih1y weathered, dark greenish-brown -
METAVOLCANIC ROCK, highly jointed
.4
- TRENCH TERMINATED AT 5 FEET DUE TO
REFUSAL ON ROCK
1
Fhrnre A-6. Log of Trench T 6 - I • - S bFItL
SAMPLING UNSUCCESSFUL II ... STANDARD PENETRATION TEST U ... DRIVE SAMPLE (UNDISTURBED) I SAMPLE SYMBOLS 10 .
-
... DISTURBED OR BAG SAMPLE ... CHUNK SAMPLE ... WATER TABLE OR SEEPAGE
NOTE: THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE
DATE INDICATED. IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES. -
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PROJECT NO. 06721-12-01
TRENCH T7
DEPTH
IN SAMPLE 0 o SOIL H
u.. ..
FEET
CLASS ELEV. (MSL.) 388 DATE COMPLETED 5/8/01
H (USCS)
EQUIPMENT JD 410 D
MATERIAL DESCRIPTION
TOPSOIL
- T7-1 CL Stiff to very stiff, moist, brown to olive, Sandy -
CLAY
SANTIAGO PEAK METAVOLCANICS
4 - Highly weathered, highly fractured, light green, -
• METAVOLCANIC ROCK, joints filled with
-
- L pistachio green clay with soapy feel -
T7-2 r-L 6
è • 4
i - -
- c-L
8
TRENCH TERMINATED AT 8 FEET
Figure A-7. Lo Trench T 7
I•
NOTE: THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE
DATE INDICATED. IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
I ' •, - -- -- -
SHEL
SAMPLE SYMBOLS U ... SAMPLING UNSUCCESSFUL E .. STANDARD PENETRATION TEST U ... DRIVE SAMPLE (UNDISTURBED)
DISTURBED OR BAG SAMPLE ... CHUNK SAMPLE • ... WATER TABLE OR SEEPAGE
PROJECT NO. 06721-12-01
CO I- TRENCH T8
DEPTH SOIL
- V 0 •
j LUX
' SAMPLE
ELEV. (MSL.) 378 DATE COMPLETED 5/8/01
•
EQUIPMENT JD41OD
-0 - MATERIAL DESCRIPTION
7-, ALLUVIUM
- . Stiff to very moist, brown, Sandy CLAY - V
-2 -
:-- CL V -
4.
/ . SANTIAGO FORMATION V V • Stiff, very moist, green, CLAY, fractured with -
V / V shiny parting surfaces with localized shearing
-6 - / CH -
- 8
10 - V
-Becomes less weathered, less fractured -
12.: -
_
-
•
V TRENCH TERMINATED AT 13 FEET
Fliure A-8. Log of Trench T SHEL
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NOTE: THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE V DATE INDICATED. IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
IV
'V • •V -
I - -
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V E SAMPLING-UNSUCCESSFUL 11 ... STANDARD PENETRATION TEST 0 ... DRIVE SAMPLE (UNDISTURBE ...D) SAMPLE SYMBOLS V
- ... DISTURBED OR BAG SAMPLE LJ ... CHUNK SAMPLE ... WATER TABLE OR SEEPAGE
I PROJECT NO. 06721-12-01 -
TRENCHT.9
DEPTH SOIL H
IN
FEET
SAMPLE
NO.
o I a Z CLASS ELEV. (MSL.) 382 DATE COMPLETED 5/8/01
u_
w a
...
z a (USCS) WHO • H
• - EQUIPMENT JD 410D
O_'— 0 C..)
MATERIAL DESCRIPTION
-0 -
CL TOPSOIL.
- Stiff, moist, dark brown, Sandy CLAY -
j CL
/,. ____
SANTIAGO FORMATION
- \Stif, moist, light green, CLAY -
SANTIAGO PEAK METAVOLCANICS - / 4 - Highly weathered, dark greenish-brown, -
METAVOLCANIC ROCK, highly jointed
/-•
- 4NL.. - -
- 6
TRENCH TERMINATED AT 6 FEET
Figure A-9. Loc! of Trench T 9
SAMPLE SYMBOLS ... SAMPLING UNSUCCESSFUL IJ ... STANDARD PENETRATION TEST U ... DRIVE SAMPLE (UNDISTURBED)
DISTURBED OR BAG SAMPLE • .. CHUNK SAMPLE ... WATER TABLE OR SEEPAGE
NOTE: THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES. ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE
DATE INDICATED. IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
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PROJECT NO. 0721-12-01 .
TRENCH T10 z
DEPTH SAMPLE . • SOIL w
FEET wo. CLASS ELEV. (MSL.) 388 DATE COMPLETED 5/8/01
EQUIPMENT JD 410 D
MATERIAL DESCRIPTION
OT
TOPSOIL
/ Firm, moist, dark brown, Sandy CLAY
yCL. .
-
v . . SANTIAGO PEAK METAVOLCANICS
4 Highly weathered, dark greenish-brown,
METAVOLCANIC ROCK, highly jointed,
- excavates to angular rock to 4 inches
6 7
.
TRENCH TERMINATED AT 6 FEET
Fhmre A-10. Loc! of Trench T 10
ML
U ... SAMPLING UNSUCCESSFUL Iii ... STANDARD PENETRATION TEST I ... DRIVE SAMPLE (UNDISTURBED) 1 [SAMPLE SYMBOLS
DISTURBED OR BAG SAMPLE ... CHUNK SAMPLE •.. WATER TABLE OR SEEPAGE
I NOTE: THE LOG OF SUBSURFACE. CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE
DATE INDICATED. IT IS NOT WARRANTED.TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
I
PROJECT NO. 06721-12-01
CY- TRENCH T11
DEPTH SAMPLE o o SOIL .
.
LL Q C \
H'
zU_ IN NO. CLASS ELEV. (MSL.) 398 DATE COMPLETED 5/8/01 nu w z FEET H (USCS) UJU)O •LLJ 0
'EQUIPMENT JD 410 D
MATERIAL DESCRIPTION S
0 -
/ TOPSOIL
-
- T11-1 CL Firm, moist, dark brown, CLAY, trace. sand, trace -
/ small gravel
:2: T.,
r- SANTIAGO PEAK METAVOLCANICS -
1- v t High weathered, dark olive and rust,
- 4 - METAVOLCANIC ROCK -
Vj -Becomes less weathered, highly jointed, excavates
- - '- to 6 inches angular -
- 6 - -
TRENCH TERMINATED AT 7 FEET
Figure A-li, Log of Trench T ii SHEL'
Li E AMPLE SYMBOLS ... SAMPLING UNSUCCESSFUL II ... STANDARD PENETRATION TEST U... DRIVE SAMPLE (UNDISTURBED)
Es DISTURBED OR BAG SAMPLE, ... CHUNK SAMPLE Y ... WATER TABLE OR SEEPAGE
I
NOTE: THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE
DATE INDICATED. IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
I
Figure A-12, Log of Trench T 12 5
• SHEL
I 0 SAMPLE SYMBOLS ... SAMPLING UNSUCCESSFUL
.
... STANDARD PENETRATION TEST .. DRIVE SAMPCE (UNDISTURBED) I
DISTURBED OR BAG SAMPLE ... CHUNK SAMPLE ... WATER TABLE OR SEEPAGE
PROJECT NO. 06721-12-01
TRENCH T12 '
D. <
DEPTH SAMPLE SOIL
IN
FEET NO. Cl. 'ELEV.. (MSL.) 430 DATE COMPLETED 5/8/01
EQUIPMENT JD410 D '-'
0 0
MATERIAL DESCRIPTION
SC TOPSOIL
Loose, slightly moist, Clayey, fine SAND - -
-2 -
v SANTIAGO PEAK METAVOLCANICS -
-. '- . Highly weathered, dark greenish-brown, -
METAVOLCANIC ROCK, highly jointed,
- 4 - ______ - ______ excavates to angular boulder up to 18 inch
- '\diameter
TRENCH TERMINATED AT 4 FEET DUE TO
•
-
REFUSAL
I
NOTE: THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE
DATE INDICATED. IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
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PROJECT NO. 06721-12-01
TRENCH' T 13
DEPTH SAMPLE SOIL
FEET NO. ELEV.(MSL.) 450 DATE COMPLETED 5/8/01
Hui
EQUIPMENT : JD 410 D W 00 ix 0
MATERIAL DESCRIPTION
A. TOPSOIL/COLLUVIUM
- Dense, slightly moist, brown-red, Clayey, fine • SC SAND with silt .
2 T13-1
Very stiff, moist, gre:thshrown, CLAY with r
-
CL angular rock
- 6 - - - -
•• v SANTIAGO PEAK METAVOLCANICS
Highly weathered, dark greenish-brown,
META VOLCANIC ROCK, highly jointed,
8 - ______ - ______ excavates to 8 inches max angular with clay
TRENCH TERMINATED AT 8 FEET
'S
SAMPLE SYMBOLS E ... SAMPLING UNSUCCESSFUL 11 ... STANDARD PENETRATION TEST ... DRIVE SAMPLE (UNDISTURBED)
] DISTURBED OR BAG SAMPLE 10 ... CHUNK SAMPLE ... WATER TABLE OR SEEPAGE
I
NOTE: THE LOG OF SUBSURFACE- CONDITIONSSHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE
DATE INDICATED. IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
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Figure A-13, Log of Trench T 13 SHEL
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Sample Moisture Content (%) Dry Density Expansion
No. (pci) Index Classification
Before Test - After Test
T5-1 11.7 24.9 - 104.5 11 Very Low
T13-1 11.1 27.3 106.2 57 Medium
June 26, 2006
I .
I APPENDIX B
LABORATORY TESTING
I Laboratory tests were performed in accordance with generally accepted test methods of the American
I Society for Testing and Materials (ASTM) or other suggested procedures. Selected, soil samples were
analyzed for maxiiiurn dry density and optimum moisture content, expansion potential, and shear
I
strength characteristics The results of the laboratory tests are presented in Tables B-I through B-III.
TABLE B-I
I , SUMMARY OF LABORATORY MAXIMUM DRY DENSITY AND
OPTIMUM MOISTURE CONTENT TEST RESULTS
ASTMD 1557-00
Maximum Optimum MOisture
Sample No. Description Dry Density Content (% dry"
(pci) weight)
T5-1 Dark brown, Clayey, fine SAND 121.3 125
T,13-1 Reddish brown, fine SAND with Silt 121.4 12 6
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TABLE B-11
SUMMARY OF LABORATORY DIRECT SHEAR TEST RESULTS
ASTM D 3080-90
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Sample No. Dry Density Moisture Content Unit Cohesion Angle of Shear
(pci) (%) ' (psi) Resistance (degrees)
T5-1 1093 / 124 400 28
Soil sample remolded to 90 percent relative density at near optimum moisture content:
TABLE B-Ill'
SUMMARY OF LABORATORY EXPANSION INDEX TEST RESULTS
ASTM D 4829-95 .
I S S S
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I APPENDIX C (
I RECOMMENDED GRADING SPECIFICATIONS
/ FOR. .
1 -• S . . p. .......................
...S \- #SHELLEYpROPERT
I 4 ,CARLSBAD, CALIFORNIA
PROJECT NO 06721-12-02
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I RECOMMENDED GRADING SPECIFICATIONS
1. GENERAL
1 1.1. These' Recommended Grading Specifications shall• be used in conjunction with the
Geotechnical Report for the project prepared. -by Geocon Incorporated. The
I recommendations contained in-the text of the Geotechnical. Report are a part of the
earthwork and grading specifications and shall supersede the provisions contained
hereinafter in the case of conflict.
1.2. Prior to the commencement of grading, a geotechnical consultant (Consultant) shall.be
I employed for the purpose' of observing. earthwork procedures and testing the,, fills for
substantial conformance with the recommendations of the Geotechnical Report and these ' specifications. It will be necessary that the Consultant provide adequate testing and
observation services so that he may determine that, in his opinion, the work was performed
in substantial conformance with these specifications,:,It shall be the responsibility of the
Contraôtor to assist the Consultant and keep him' appiised of work schedules and changes
so that personnel may be scheduled accordingly:
1.3. It shall be the sole responsibility of the Contractor to provide adequate equipment and
I ..methods 'to accomplish the work in - accordance with applicable grading codes or agency
ordinances, these specifications and the approved grading plans. If, in the opinion of the
Consultant, unsatisfactory conditions such as questionable soil materials, poor moisture
I , condition, inadequate compaction, adverse weather, and so forth, result in a quality of work
not in conformance with these specifications, the Consultant will be empowered to reject
the work and recommend to the Owner that construction be stopped until the unacceptable
conditions are corrected.
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2. DEFINITIONS
I 2.1. Owner shall refer to the owner of the property or the entity on whose behalf the grading
work is being performed and who has contracted with the Contractor to have grading
performed.
I •.' 2.2. 'Contractor shall refer to the Contractor performing the site grading work.
2.3. , Civil Engiñeer•or Engineer of Work shall refer to the California licensed Civil Engineer
or consulting firm responsible for preparation of the grading plans, surveying and verifying
I as-graded topography. •
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2.4. Consultant shall refer to the soil engineering and engineering geology consulting firm
retained to provide geotechnical services for the project.
2.5. Soil Engineer shall refer to a California licensed Civil Engineer retained by the Owner,
- who is experienced in the practice of geotechnical engineering. The Soil Engineer'shall be
responsible for having qualified representatives on-site to observe and test the Contractors
work for conformance with-these specifications.
2.6. Engineering Geologist shall refer to a California licensed Engineering Geologist retained
by the Owner to provide geologic observations and recommendations during the site
grading.
2.7. Geotechnical Report shall refer to a soil report (including all addenda) which may include
a geologic reconnaissance or geoldgic investigation that was prepared specifically for the
development of the project for which these Recommended Grading Specifications are
intended to apply.
3. MATERIALS
3.1. Materials for compacted fill shall consist of any soil excavated from the cut areas or
imported to the site that, in the opinion of the Consultant, is suitable for use in construction
of fills. In general, fill materials can be classified as soil fills, soil-rock fills or rock fills, as
defined below.
3.1.1. Soil fills are defined as fills containing no rocks or hard lumps greater than 12
inches in maximum dimension and containing at least 40 percent by weight of
material smaller than 3/4 inch in size.
( (
3.1.2. Soil-rock fills are defined as fills containing no rocks or hard lumps larger. than 4
feet in maximum dimension and containing a sufficient matrix of soil fill to allow
for proper compaction of soil fill around the rock fragments or hard lumps as
specified in Paragraph 6.2. Oversize rock is defined as material greater than 12
inches,
3.1.3. Rock fills are defined as fills containing no rocks or hard lumps larger than 3 feet
in maximum dimension and containing little or no fines. Fines are defined as
material smaller than 3/4 inch in- maximum dimension. The quantity of fines shall
be less than approximately 20 percent of the rock fill quantity.
GI rev. 07/02
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3.2. Material of a perishable, spongy, or otherwise unsuitable nature as determined by the
I Consultant shall not be usedin fills.
'I .3.3. Materials used for fill, either imported or on-site, shall not contain hazardous materials as
defined by the California Code of Regulations, Title 22, Division 4, Chapter 30, Articles 9
and 10; 40CFR; and any other applicable local, state or federal laws. The Consultant shall
I not be responsible for the identification or analysis of the potential presence of hazardous
materials. However, if observations, odors or soil discoloration cause Consultant to suspect
I the presence of hazardous materials, the Consultant may request from the Owner the
termination of grading operations within the affected area. Prior to resuming grading
operations, the Owner shall provide a written report to the Consultant indicating that the
I suspected materials are not hazardous as defined by applicable laws and regulations.
I 3.4. The outer 15 feet of soil-rock fill slopes, measured horizontally, should be composed of
properly compacted soil fill materials approved by the Consultant. Rock fill may extend to
the slope face, provided that the slope is not steeper than 2:1 (horizontal: vertical) and a soil I layer no thicker than 12 inches is track-walked onto the face for landscaping purposes. This
procedure may be utilized, provided it is acceptable to the governing agency, Owner and
I Consultant. .
I 3.5. Representative samples of soil materials to be used for fill shall be tested in the laboratory
by the Consultant to determine the maximum density, optimum moisture content, and,
I .
where appropriate, shear strength, expansioñ,and gradation characteristics of the soil.
3.6. During grading, soil or groundwater conditions other than those identified in the
I Geotechnical Report may be encountered by the Contractor. The Consultant shall be
notified immediately to.eval'uate the significance of the unanticipated condition
4. CLEARING AND PREPARING AREAS TO BE FILLED
4.1. Areas to be excavated and filled shall be cleared and grubbed. Clearing shall consist of
complete removal above the ground surface of trees, stumps, brush, vegetation, man-made
structures, and similar debris. Grubbing shall consist of removal of stumps, roots, buried
logs and 'other unsuitable material and shall be performed in areas to be graded.-Roots and
other projections exceeding 1-1/2 inches. in diameter shall be removed to a depth of 3 feet
below the surface of the ground,. Borrow areas shall be grubbed to the extent necessary to
provide suitable fill materials.
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4.2. Any asphalt pavement material removed during clearing operations should be properly
disposed at an approved off-site facility. Concrete fragments which are free of reinforcing
steel may be placed in fills, provided they are placed in accordance with Section 6.2 or 6.3
of this document.
4.3. After clearing and grubbing of organic matter or other unsuitable material, loose or porous
soils shall be removed to the depth recommended in the Geotechnical Report. The depth of
removal and compaction shall be observed and approved by a representative of the
Consultant. The exposed surface shall then be plowed or scarified to a minimum depth of 6
inches and until the, surface is free from uneven features that would tend to prevent uniform
compaction by the equipment to be used.
4.4. Where the slope ratio of the original, ground is steeper than 6:1 (horizontal:vertical), or
where recommended by the Consultant, the original ground should be benched in
accordance with the following illustration.
TYPICAL BENCHING DETAIL
Finish Grade Original Ground
1 Finish Slope Surface
Remove All
- Unsuitable Material
As Recommended By Slope To Be Such That Soil Engineer Sloughing OrSliding
Varies Does Not Occur
See Note I See Note 2
No Scale
DETAIL NOTES: (1) Key width "B" should be a minimum of 10 feet wide, or sufficiently wide to
permit complete coverage with the compaction equipment used. The base of the
key should be graded horizontal, or inclined slightly into the, natural slope.
(2) The outside of the bottom key should be below the topsoil or unsuitable surficial
material and at least 2 feet into dense formational material. Where hard rock is
exposed in the bottom of the key, the depth and configuration of the key may be
modified asapproved by the Consultant.
GI rev. 07/02
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4.5. After areas to receive fill have been cleared, plowed or scarified, the surface should be
disced or bladed by the-Contractor until it is uniform and free from large clods. The area
should then be moisture conditioned to achieve the proper moisture content, and compacted
as recommended in Section 6.0 of these specifications.
5. COMPACTION EQUIPMENT.
5.1. Compaction of soil or soil-rock fill shall be accomplished by sheepsfoot or segmented-steel
wheeled rollers, vibratory rollers, multiple-wheel pneumatic-tired rollers, or other types of
acceptable compaction equipment. Equipment shall be of such a design that it will be
capable of compacting the soil or soil-rock fill to the specified relative compaction at the
specified mdisture content.
5.2. Compaction of rock fills shall be performed in a'ccordance with Section 6.3.
6. PLACING, SPREADING AND COMPACTION OF FILL MATERIAL
6.1. Soil fill, as defined 7in Paragraph 3 11, shall be placed by the Contractor in accordance with
the following recommendatio'ñs -
6.1.1. Soil fill shall be placed by the Contractor in layers that, when compacted, should
generally not exceed 8 inches. Each layer shall be spread evenly and shall be
thoroughly mixed during spreading to obtain uniformity of material and moisture
- in each layer. The entire fill shall be constructed as a unit in nearly level lifts. Rock
materials greater than 12 inches in maximum dimension shall be placed in
accordance with Section 6.2 or 6.3 of these specifications.
6.1.2. In general, the soil fill shall be compacted at a moisture content at. or above the
optimum moisture content as determined by ASTM D1557-00.
6.1.3. ;When the moisture content of soil fill is below that specified by the Consultant,
water shall be added by the Contractor until the moisture content is in the range
specified.
6.1.4. When the moisture content of the soil fill is above the range specified by the
Consultant or too wet to achieve proper compaction, the soil fill shall be aerated by
- the Contractor by blading/mixing, or other satisfactory methods until the moisture
content is within-the range specified.
GI rev. 07/02
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6.1.5. After each layer has been placed, mixed, and spread evenly, it shall be thoroughly
I compacted by the Contractor to a relative compaction of at least 90 percent.
Relative compaction is defined as the ratio (expressed in percent) of the in-place
I dry density of the compacted fill to the maximum laboratory dry density as'
' determined in-accordance, with ASTM.D1557-00. Compaction shall be continuous
over the entire area, and compaction equipment shall make sufficient passes so that
I, the specified' minimum , relative compaction has been achieved throughout the
entire fill.
6.1.6. Soils having an Expansion Index of greater than 50 may be used in fills if placed at ' least 3 feet below finish pad grade and should be compacted at a moisture content
generally 2 to 4 percent greater than the optimum moisture content for the material.
1 6.1.7. Properly compacted soil fill shall extend to the design surface of fill slopes. To
achieve proper compaction;' it is recommended that fill slopes be over-built by at
I least 3 feet and then cut to the design grade. This procedure is considered
preferable to track-walking of slopes, as described in the following paragraph.
I 6.1.8. As an alternative to over-building of slopes, slope faces may be back-rolled with a
heavy-duty loaded sheepsfoot or vibratory roller at maximum 4-foot fill height
I intervals. Upon completion, slopes should then be track-walked with a D-8 dozer
or similar equipment, such that a dozer track covers all slope surfaces at least
I
'twice.
6.2. Soil-rock fill, as defined in Paragraph 3.1.2, shall be placed by the Contractor in accordance
with the following recommendations:
I' 6.2.1. Rocks larger than 12 inches but less than 4 feet in maximum dimension may be
incorporated into the compacted soil fill, but shall be limited to the area measured
15 feet minimum horizontally from the slope, face and 5 feet below finish grade or
I ' ,
3 feet below the deepest utility, whichever is deeper.
I 6.2.2. Rocks or rock fragments up to 4 feet in maximum dimension may either be
individually placed or placed' in windrows. Under certain conditions, rocks or rock
fragments up to 10 feet in maximum dimension may be placed using similar
I methods. The acceptability of placing rock materials greater than 4 feet in
maximum dimension shall be evaluated during grading as specific cases arise and.
I 'shall be approved by the Consultant prior to placement.
GI rev. 07/02
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6.2.3. For individual placement, sufficient space shall be provided between rocks to allow
I . for passage of compaction equipment.
I 6.2.4. For windrow placement, the rocks should be placed in trenches excavated in
properly compacted soil fill. Trenches should be approximately 5 feet wide and 4
feet deep in maximum dimension. The voids around and beneath rocks should be
I filled with approved granular soil having a Sand Equivalent of 30 or greater and
should be compacted by flooding. Windrows may also be placed utilizing an
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"open-face" methbd in lieu of the trench procedure, however, this method should
first be approved by the Consultant.
1 6.2.5. Windrows should generally be parallel to each other and may be placed either
parallel to or perpendiculr to the face of the slope depending on the site geometry.
I / The minimum horizontal spacing for windrows shall be 12 feet center-to-center .
with a 5-foot stagger or offset from lower courses to next overlying course. The
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minimum vertical spacing between windrow courses shall be 2 feet from the top of
a lower windrow to the bottom of the next higher Windrow.
1 6.2.6. All rock placement, fill placement and flooding of approved granular soil in the
windrows must be continuously observed by the Consultant or his representative.
1 6.3. Rock fills, as defined in Section 3.1.3., shall be placed by the Contractor in accordance with
the following recommendations:
6.3.1: The base of the rock fill shall be placed on a sloping surface (minimum slope of 2
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percent, maximum slope of 5 percent). The surface shall slope toward suitable
subdrainage outlet facilities. The rock fills shall be provided with subdrains during
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construction so that a hydrostatic pressure buildup does not develop. The subdrains
shall be permanently connected to controlled drainage facilities to control post--
. . constrction infiltration of water.
6.3.2. Rock fills shall be placed in lifts not exceeding 3 feet. Placementshall be by rock
I . trucks traversing previously placed lifts and dumping at the edge of the currently
placed lift. Spreading of the rock fill shall be by dozer to facilitate seating of the
rock. The rock fill shall be watered heavily during placement. Watering shall
I consist of water trucks traversing in front of the current rock lift face and spraying
water continuously during rock placement. Compaction equipment with
1 . compactive energy comparable to or greatei than that of a 20-ton steel vibratory
roller or other compaction equipment providing suitable energy to achieve the
required compaction. or deflection as recommended in Paragraph 6.3.3 shall be
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utilized. The number of passes to be made will be determined as described in
Paragraph 6.3.3. Once a rock fill lift has been covered with soil fill, no additional
rock fill lifts will be permitted over thesoil fill.
6.3.3. Plate bearing tests, in accordance with ASTM Dl 196-93, may be performed in
both the compacted soil fill and in the rock fill to aid in determining the number of
passes of the compaction equipment to be performed. If performed, a minimum of
three plate bearing tests shall be performed in the properly compacted soil fill
(minimum relative compaction of 90 percent). Plate bearing tests shall then be
performed on areas of rock fill having two passes, four passes and six passes of the
compaction equipment, respectively. The number of passes required for the rock
fill shall be determined by comparing the results of the plate bearing tests for the
soil fill and the rock fill and by evaluating the deflection variation with number of
passes. The required number of passes of the compaction equipment will be
performed as necessary until the plate bearing deflections are equal to or less than
that'determined for the properly compacted soil fill. In no case will the required
number of passes be less than two.
6.3.4. A representative of the Consultant shall be present during rock fill operations to
verify that the minimum number of "passes" have been obtained, that water is
being properly applied and that specified procedures are being followed. The actual
number of plate bearing tests will be determined by the Consultant during grading.
In general, at least one test should be performed for each approximately 5,000 to
10,000 cubic yards of rock fill placed.
6.3.5. Test pitsshall be excavated by the Contractor so that the Consultant can state that,
in his opinion, sufficient water is present and that voids between large rocks are
properly filled with smaller rock material. In-place density testing will not be
required in the rock fills.
6.3.6. To reduce the potential for "piping" of fines into the rock fill from overlying soil
fill material, a 2-foot layer of graded filter material shall be placed above the
uppermost lift of rock fill. The need to place graded filter material below the rock
should be determined by the Consultant prior to commencing grading. The
gradation of the graded filter material will be determined at the time the rock fill is
being excavated. Materials typical of the rock fill should be submitted to the
Consultant in a timely manner, to allow design of the graded filter prior to the
commencement of rock fill placement.
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6.3.7. All rock fill placement shall be continuously observed during placement by
representatives of the Consultant.
7. OBSERVATION AND TESTING
7.1. The Consultant shall be the Owners representative to observe and perform tests during
clearing, grubbing, and filling and compaction operations. In general, no more than 2 feet
in vertical elevation of soil or soil-rock fill shall be placed without at least one field density
test being performed within that interval. In addition; a minimum of one field density test
shall be performed for every 2,000 cubic yards of soil or soil-rock fill placed and
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7.2. The Consultant shall perform random field density tests of the compacted soil or soil-rock
fill to proyide a basis for expressing an opinion as to whether the fill material is compacted
as specified. Density tests shall be performed in the compacted materials below any
disturbed surface. When these tests indicate that the density of any layer of fill or portion
thereof is below that specified, the particular layer or areas represented by the, test shall be
reworked until the specified density has been achieved.
7.3. During placement of rock fill, the Consultant shall verify that the minimum number of
passes have been obtained per the criteria discussed in Section 6.3.3. The Consultant shall
request the excavation Of observation pits and may perform. plate bearing tests on the
placed rock fills. The observation pits will be excavated to provide a basis for expressing
an opinion as to whether the rock fill is properly seated and sufficient moisture has been
applied to the material. If performed, plate bearing tests will be performed randomly on the
surface of the most-recently placed lift. Plate bearing tests will be performed to provide a
basis for expressing an opinion as to whether the rock fill is adequately seated. The
maximum deflection in the rock fill determined in Section 6.3.3 shall be less than the
maximum deflection of the properly compacted soil fill. When any of the above criteria
indicate that a layer of rock.fill or any portion thereof is below that specified, the affected
layer or area shall be reworked until the rock fill has been adequately seated and sufficient
moisture applied.
7.4. A settlement monitoring program designed by the Consultant may be conducted in areas of
rock fill placement. The specific design of the monitoring program shall be as
recommended in the Conclusions and Recommendations section of the project
Geotechnical Report or in the final report of testing and observation services performed
during grading.
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7.5 The Consultant shall observe the placement of subdrains, to verify that the drainage devices
have been placed and constructed in substantial conformance with project specifications.
7.6. Testing procedures shall conform to the following Standards as appropriate:
7.6.1. Soil and Soil-Rock Fills:
7.6.1.1. Field Density Test, ASTM D1556-00, Density of Soil In-Place By the
Sand-Cone Method.
7.6.1.2. Field Density Test, Nuclear Method, ASTM D2922-96, Density of Soil and
Soil-Aggregate In-Place by Nuclear Methods (Shallow Depth).
7.613. Laboratory Compaction Test, ASTM D1557-00, Moisture-Density
Relations of Soils and Soil-Aggregate Mixtures Using 10-Pound Hammer
and 18-Inch Drop.
7.6. 1.4. Expansion Index Test, ASTM D4829-95, Expansion Index Test.
7.6.2. Rock Pills
7.6.2.1. Field Plate Bearing Test, ASTM D1196-93 (Reapproved 1997) Standard
Method for Nonreparative Static Plate Load Tests of Soils and Flexible
Pavement Components, For Use in Evaluation and Design of Airport and
Highway Pavements. -
8. PROTECTION OF WORK
During construction, the Contractor shall properly grade all excavated surfaces to provide
positive drainage and prevent ponding of water. Drainage of surface water shall be
controlled to avoid damage to adjoining properties or to finished work on the site. The
Contractor shall take remedial measures to prevent erosion of freshly graded areas until
such time as permanent drainage and erosion control features have been installed. Areas
subjected to erosion or sedimentation shall be properly prepared in accordance with the
Specifications prior to placing additional fill or structures.
M. After completion of grading as observed and tested by the Consultant, no further
excavation or filling shall be conducted except in conjunction with the services of the
Consultant.
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9. CERTIFICATIONS AND FINALREPORTS
9.1. Upon completion of the work, Contractor shall furnish Owner a certification by the Civil
Engineer stating that the lots 'and/or building pads are graded to within 0.1 foot vertically of
elevations shown on the grading plan and that all tops and toes of slopes are within 0.5 foot
horizontally of the positions shown on the grading plans. After installation of a section of
subdrain, the project Civil Engineer should survey its location and prepare an as-built plan
of the subdraiñ location. The project Civil Engineer should verify the proper outlet for the
subdrains and the Contractor should ensure that the drain system is free of obstructions.
9.2. The Owner is responsible for furnishing a final as-graded soil and geologic report
- satisfactory to the appropriate governing or accepting agencies. The as-graded report -
should be prepared and signed by a California licensed Civil Engineer experienced in
geotechnical engineering and by. a California Certified Engineering Geologist, indicating
that the geotechnical aspects of the grading . were performed in substantial conformance
with the Specificati6ns or approved changes to the Specifications.
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