HomeMy WebLinkAboutCT 00-20; FOX-MILLER PROPERTY; UPDATE GEOTECHNICAL INVESTIGATION; 2004-04-22GEOCON
INCORPORATED
GEOTECHNICAL CONSULTANTS
Project No. 07238-42-01
April 22, 2004
H. G. Fenton Company, Incorporated
7588 Metropolitan Drive
San Diego, Califomia 92108
Attention: Mr. Allen Jones
Subject: CARLSBAD TRACT CT-00-20
CARLSBAD, CALIFORNIA
UPDATE GEOTECHNICAL INVESTIGATION
Gentlemen:
In accordance with your authorization of our proposal No. LG-04013 dated January 12, 2004; we
have performed a supplemental geotechnical investigation at the subject property. The study was
conducted to augment and update previous studies for the site in order to evaluate stability of
proposed cut slopes and to provide grading recommendations for development of the property.
The accompanying report describes the site soil and geologic conditions and provides updated
grading recommendations and foundation design criteria. Geotechnical conditions that will require
special consideration include a relatively large undocumented fill with large oversize chunks of
concrete within the southeastem margins of the property and localized shallow clay seams that exist
within one of the proposed cut slopes. The site is considered suitable for the planned development
provided the recommendations of this report are followed.
Should you have questions regarding this update report, or if we may be of further service, please
contact the undersigned at your convenience.
Very truly yours,
GEOCON INCORPORATED
JLB:GCC:dmc
(3/del)
(1)
(1)
(4/del)
Addressee
Ladwig Design Group
Attention: Mr. Bob Ladwig
Newport National
Attention: Mr. Scott Bmsseau
O'Day Consultants
Attention: Mr. John Strominger
6960 Flanders Drive • San Diego, California 92121-2974 • Telephone (858] 558-6900 • Fax (858) 558-6159
TABLE OF CONTENTS
1. PURPOSE AND SCOPE 1
2. SITE AND PROJECT DESCRIPTION 2
3. SOIL AND GEOLOGIC CONDmONS 2
3.1 Undocumented Fill (Qudf) 3
3.2 Previously Placed Fill (Qpf) 3
3.3 Topsoil (uimiapped) 3
3.4 Alluvium (Qal) 3
3.5 Point Loma Formation (Kpl) 4
4. GROUNDWATER 6
5. GEOLOGIC HAZARDS 6
5.1 Faulting and Seismicity 6
5.2 Liquefaction Potential 7
6. CONCLUSIONS AND RECOMMENDATIONS 8
6.1 General g
6.2 Seismic Design Criteria 8
6.3 Soil and Excavation Characteristics 9
6.4 Grading 9
6.5 Subdrains H
6.6 Slopes 12
6.7 Foundations 12
6.8 Retaining Walls and Lateral Loads 14
6.9 Slope Maintenance 15
6.10 Drainage 15
6.11 Grading Plan Review 16
LIMITATIONS AND UNIFORMITY OF CONDITIONS
MAPS AND ILLUSTRATIONS
Figure 1, Vicinity Map
Figure 2-6, Geologic Map (Map Pocket)
Figure 7-10, Geologic Cross Sections
Figure 11-15, Slope Stability Analyses
Figure 16, Surficial Slope Stability Analysis
Figure 17, Typical Canyon Subdrain Detail
Figure 18, Recommended Subdrain Cut-Off Wall
Figure 19, Subdrain Outlet Headwall Detail
APPENDIX A
FIELD INVESTIGATION
Figure A-1, Log of Borings
Figures A-2 - A-16, Logs of Trenches
TABLE OF CONTENTS (Continued)
APPENDIX B
LABORATORY TESTING
Table B-I, Summary of Laboratory Maximum Dry Density and Optimum Moisture Content Test Results
Table B-E, Summary of Direct Shear Test Results
Table B-III, Summary of Laboratory Density from Submerged Wax Sample
APPENDK C
RECOMMENDED GRADING SPECIFICATIONS
LIST OF REFERENCES
UPDATE GEOTECHNICAL iNVESTiGATiON
1. PURPOSE AND SCOPE
This report presents the results of an update geotechnical investigation for Carlsbad Tract CT 00-20
located adjacent to the west side of El Camino Real and north of Faraday Drive in the City of
Carlsbad, Califomia (see Vicinity Map, Figure 1). The purpose of our study was to update previous
studies performed for the property and perform additional field studies to evaluate excavation
characteristics and slope stability of proposed cut slopes. Conclusions and recommendations
presented herein are based upon the conditions encountered.
The scope of the investigation consisted of a site reconnaissance, review of published geologic
literature pertinent to the site, and conducting a field investigation. In addition, we have reviewed
numerous geotechnical investigations for the property prepared by AGRA, AMEC and Leighton and
Associates. A detailed list of previous geotechnical investigations reviewed is summarized in the List
of References at the end of this report. Development plans reviewed include the following:
1. Tentative Map For Fox-Miller Property, (reduced copy) with portion of three sheets
depicting slopes that may require buttressing, undated.
2. Grading Plans For: Carlsbad Tract CT 00-20 Fox-Miller Property, prepared by Buccola
Engineering, Inc., dated February 4, 2004.
Our field investigation was conducted between March 29 and April 3, 2004, and consisted of
geologic mapping and excavation of one large-diameter boring and 14 exploratory backhoe trenches.
Trenches were located in areas of planned cut slopes to evaluate contacts, lithology and structural
attitudes of the Point Loma Formation. The approximate locations of the exploratory excavations are
shown on Figures 2 through 6 (Geologic Map, map pocket). The geologic maps also include
approximate locations of previous borings and trenches from earlier studies. Boring and trench logs
are included in Appendix A.
The base map used to plot boring and trench locations consisted of a copy of the above-referenced
grading plans prepared by Buccola Engineermg, Incorporated, dated Febmary 4, 2004 that were
provided to us on an electronic AutoCAD file.
Laboratory tests were performed on soil samples obtained from the exploratory excavations to
determine pertinent physical soil properties. Test results are summarized in Appendix B.
Project No. 07238-42-01 - 1 . April 22, 2004
2. SITE AND PROJECT DESCRIPTION
The site occupies approximately 54 acres of irregularly shaped land located southwest of El Camino
Real and north of Faraday Drive in the city of Carlsbad, Califomia (see Vicinity Map, Figure 1). It is
understood that a four-lot industrial subdivision is planned for the property.
Presently, the property is vacant and mostly covered with non-native grassland with some coastal
sage scrub in lower canyon areas. Topographically, northwest-trending rounded hills are dissected by
two tributary canyons and a major drainage called Letterbox Canyon. The tributary canyons drain
northward, merging into the east-to-west major drainage (see Geologic Map, Figures 2 through 6).
Site elevations range from a high of approximately 310 feet above Mean Sea Level (MSL) along the
southem boundary to a low of approximately 140 feet MSL in Letterbox Canyon near the westem
boundary. The confluences of the two tributary drainages with Letterbox Canyon are located where
planned fill slopes on the order of 60 feet high will be constructed.
Review of the referenced Tentative Map indicates site development will consist of mass grading to
construct four large sheet-graded pads industrial pads with associated streets, underground utilities,
and surface improvements. Access to the site will be via an extension of Salk Avenue that will cross
the site and intersect with existing El Camino Real. Grading will be fairly significant, consisting of
cuts and fills on the order of 40 feet and 60 feet, respectively. Slopes are proposed at inclinations of
2:1 (horizontal:vertical) with slope maximum heights on the order of 40 feet for cut slopes and 60
feet for fill slopes. Localized cut slopes proposed at inclinations of 1.5:1 (horizontal:vertical) are also
planned near the intersection of Salk Avenue with El Camino Real (see Geologic Map, Figure 3).
This cut will lower an existing 1:1 cut slope on a portion of the site bordering El Camino Real.
The locations and descriptions of the site and proposed development are based on a site
reconnaissance, review of the referenced plans and geotechnical reports, conditions encountered
during our field investigation, and our understanding of proposed development. If conditions and/or
project details vary significantly from those described above, Geocon Incorporated should be
consulted to provide additional recoinmendations and/or analyses.
3. SOIL AND GEOLOGIC CONDITIONS
Four surficial soil types and one geologic formation were encountered during our field investigation.
Surficial soils include undocumented fill, previously placed fill, topsoil, and alluvium. The geologic
formation consists of Cretaceous-age Point Loma Formation. Each of the surficial soil types and the
geologic unit are discussed below in order of increasing age.
Project No. 07238-42-01 - 2 - April 22, 2004
3.1 Undocumented Fill (Qudf)
Undocumented fills exist in several areas surrounding and extending within the site and are primarily
associated with previous adjacent developments. The largest undocumented fill extends along the
southwest margins and at the comer of proposed Lot 2 and the southeast comer of proposed Lot 3.
This undocumented fill contains significant amounts of oversize chunks of concrete and asphalt
concrete debris (see Geologic Map, Figure 3 and exploratory trenches T-3, T-4, T-13, T-13A, and
T-14). The maximum fill depth in this area exceeded 16 feet in trench T-13 and appears to extend
offsite to the southeast (see Geologic Map, Figure 3, and Cross Section A-A'). Significant settlement
of this fill offsite is evident based on observed cracks in a concrete block wall and a leaning lamppost
immediately adjacent to the southeast property liinits of the site. This fill is situated within a planned
cut slope and extends into building pads. Undocumented fill is considered unsuitable in its present
condition and will require removal and replacement with properly compacted fill.
3.2 Previously Placed Fill (Qpf)
Previously placed fill is present along the margins of the site, particularly along El Camino Real and
along the south and west boundaries of the site. Proposed cut slopes along the east side of Lot 2 may
encounter previously placed fill associated with El Camino Real (see Geologic Map, Figure 3).
Another area of previously placed fill may be encountered in planned cuts to grade a proposed
detainment basin near the west site boundary and the extension of Salk Avenue in Lot 4 (Figure 5).
Fill associated with El Camino Real and the adjacent developments may have received compactive
effort, but may be underlain by unconsolidated surficial soils in offsite peripheral areas. As such, the
fills are not suitable for support of additional fill or structures and will require removal and
recompaction in areas of planned development.
3.3 Topsoil (unmapped)
Topsoil and/or residual soil was encountered as a blanket from 1 to 4 feet thick across most of the
site. The topsoil typically consists of porous, soft, moist, dark brovm, silty clay to clayey silt. Thicker
topsoil layers were found in the upper portions of drainages and as a residuum above weathered
claystone bedrock. The topsoil exhibits iiigh. expansion (see also AGRA report, July 6, 2000)
potential and is compressible. Removal of the topsoil will be necessary in areas to receive fill and/or
site improvements.
3.4 Alluvium (Qal)
Alluvial deposits are present in the lower elevation portions of the three major drainages (see
Geologic Map, Figures 2 through 6). The alluvium generally consists of loose, dark brown, gravelly
Project No. 07238-42-01 - 3 - April 22, 2004
silt and clay indistinguishable, except in its greater thickness, from the topsoil and/or residual soils
described above. In one of the previous studies over 15 feet of alluvium was encountered near the
confluence of Letterbox Canyon and a tributary at the westem edge of proposed Lot 4. The alluvium
is not suitable in its present condition for support of stmctural fill and/or loading and will require
complete removal and recompaction.
3.5 Point Loma Formation (Kpl)
The Cretaceous-age Point Loma Fonnation is a well-indurated marine sedimentary unit that extends
to the surface or at shallow depths beneath the entire site. This unit consists predominately of dense
to very dense, damp to moist, medium to dark, olive grayish clayey siltstone with interbedded layers
of light yellowish brown, fme sandstone. Light gray calcium-carbonate-cemented concretions are
also present in this unit. Our investigation included exploratory backhoe trenches and a single large-
diameter boring to supplement previous studies and to obtain more geologic structure data for slope
stability evaluation. Exploratory excavations were specifically located in the areas that have been
identified by previous studies as possibly needing buttress slope stabilization (AGRA report, dated
July 6, 2000). In general, we encountered dense, horizontally bedded Point Loma Fonnation
siltstones in most exploratory excavations; exceptions were local undulatory variations in dip that
inclined 10 degrees or less toward the west. A lot-by-lot summary with respect to structural attitudes
and slope stability of the Point Loma Fonnation as encountered in our exploratory excavations is as
follows:
Lot 1 A buttress approximately 400 feet long extending approximately north-south along a
proposed 25-foot-high cut slope was recommended previously by AGRA (2000). This was based on
projected adversely dipping bedding plane attitudes measured in a road-cut of El Camino Real and a
boring (B-2), both approximately 100 feet away from the proposed cut slope (see Geologic Map,
Figure 6). Geocon excavated trenches T-9 and T-10 within the proposed cut slope outline and
encountered 2 to 6 feet of surficial soil and weathered Point Loma Formation underlain by
horizontally bedded, hard, very silty claystone and siltstone. Previous studies likely encountered
irregular (undulating) bedding or discontinuous parting-planes that commonly occur in the fonnation.
However, it is the opinion of Geocon Incorporated that a buttress to stabilize the slope is
unnecessary. Moreover, an engineering geologist should observe the undulating character of the
bedding during grading to confirm bedding maintains non-adverse attitudes.
Lot 2 Previous studies recommended a buttress approximately 350 feet long paralleling the
property line along a proposed 20-foot-high cut (see Geologic Map, Figure 3). This was based on
adverse (dipping out-of-slope) bedding planes projected from a single boring approximately 200 feet
from the proposed cut slope (AGRA, 2000). Geocon excavated trenches T-11 and T-12 within the
Project No. 07238-42-01 - 4 - April 22, 2004
proposed cut slope area and encountered 1 to 4 feet of surficial fill and topsoil underlain by dense to
very dense, clayey siltstone with bedding planes striking perpendicularly or at steep angles to the
proposed cut slope and dipping from horizontal to 5 to 10 degrees parallel to the proposed slope. The
bedding undulates, averaging approximately 5 degrees dip parallel to the slope. This represents a
neutral or non-adverse condition with respect to slope stability. The westem end of the same
proposed cut slope, however, will expose the transition into the concrete-debris fill described above
that extends into Lot 3 and will require remedial grading.
Lot 3 Previous studies recommended buttressed cut slopes extending approximately 700 feet along
the south boundary of the site, again based on projected bedding-plane attitudes measured from
distant excavations (see Geologic Map, Figure 4). Geocon advanced one deep large-diameter boring
(B-l) to a depth of 55 feet that was down-hole logged by an engineering geologist, adjacent to a
proposed 40-foot-high cut slope along the southem site boundary. In addition, exploratory trenches
T-3, T-13 and T-13A were excavated in the southeast comer of the lot. The findings in the deep
boring indicated similar bedding-plane stmcture as that found in Lot 2; very low-angle undulating
bedding striking perpendicular and dipping less than 7 degrees parallel to the proposed cut slope. A
single bedding-plane-parallel shear was found at a shallow depth approximately 10 feet below
proposed finish cut grade (see Geologic Cross Sections B-B' and C-C). In addition, calcium-
carbonate cemented layers were encountered, with the thickest layer being approximately 10 inches.
It is the opinion of Geocon Incorporated that these represent neutral or non-adverse bedding
conditions that will require as-graded observation by an engineering geologist to confirm that the
locally variable bedding stmcture maintains non-adverse attitudes. The proposed buttress in the
southeast comer of Lot 3 is in the transitional area previously described above to have an
undocumented oversize concrete-debris fill. Remedial grading will be required in the southeast
portion of Lot 3 where debris-fill is encountered.
Lot 4 Buttressing of the proposed approximately 700-foot-long cut along the east-southeast lot
boundary was proposed in previous studies based on projection of adversely dipping bedding
attitudes from distant exploratory trenches (see Geologic Map, Figure 5). Geocon excavated three
trenches (see Trenches T-4, T-7 and T-8, Geologic Map, Figure 5, and Appendix A) along the
proposed cut slope. All trenches encountered horizontally bedded, dense to very dense siltstone with
interbedded thin sandstone and claystone layers. In one trench, T-7, an extremely dense, cemented
sandstone caused refusal of excavation. It is the opinion of Geocon Incorporated that the proposed
buttress is not necessary.
Project No. 07238-42-01 - 5 - April 22, 2004
4. GROUNDWATER
Groundwater was not encountered during our recent field investigation or during previous studies.
Minor wet bedding planes surfaces between approximately 44 and 55 feet in Boring B-l were
encountered and were likely the result of surface water percolating down through the upper loose
deposits and perching on the underlying very dense cemented concretion layers. Observations should
be made during grading to evaluate the presence of surficial seepage and to provide
recoinmendations for subdrains, if necessary. Subsurface drainage systems will be required at the
base of debris-fill and alluvium removals to preclude the buildup of groundwater within fills.
Groundwater is not anticipated to adversely impact the proposed development.
5. GEOLOGIC HAZARDS
5.1 Faulting and Seismicity
Review of geologic literature, observations during this study and previous geotechnical reports
prepared for the property indicate that no active faults exist on-site. The nearest active faults are the
Rose Canyon fault located approximately 5 miles west of the site and the Elsinore Fault located
approximately 24 miles east of the site. The City of Carlsbad's Geotechnical Hazard Analysis and
Mapping Study, Slieet No. 10 shows a fault exposed in the existing cut slope adjacent to El Camino
Real (AGRA, 2000). Also, Geocon's boring B-l encountered a fault that offset a cemented sandstone
layer approximately 3 inches. This is in a zone of faulting shown on the Califomia Geological
Survey geologic map (S. S. Tan and M. P. Kennedy, 1996) to be comprised of short, discontinuous
faults that displace only Pre-Holocene formations. Moreover, the fault encountered in boring B-l has
a very thin gouge zone approximately 1/8-inch wide, lined with undisturbed calcium carbonate and
iron-oxide deposits. Such coatings in arid climates are estimated to take in excess of 10,000 years to
form (Birkeland, 1984). This finding, along with the previous fault studies by AGRA (2000),
supports the opinion of Geocon Incorporated that the faults on the site are inactive.
The distance of known active faults to the site was detennined from the computer program
EQFAULT (Blake, 1989a, updated 2,000). The program estimates ground accelerations at the site for
the maximum credible and maximum probable seismic events based on distances from the site to
known Califomia active faults that have been digitized in an earthquake catalog. Principal references
used by EQFAULT in selecting faults to be included were Jennings (1994), Anderson (1984) and
Wesnousky (1986). Attenuation relationships by Sadigh (1997) were used in the analysis.
The results of the deterministic analysis indicate that the Rose Canyon fault is the dominant source
of potential ground shaking at the site. The Rose Canyon fault is estimated to have the capability to
generate a maximum credible earthquake event of Magnitude 7.2. The estimated maximum peak site
Project No. 07238-42-01 - 6 - April 22, 2004
accelerations were calculated to be 0.37g. Presented on the following table are the earthquake events
and calculated peak site accelerations for the faults most likely to subject the site to significant
ground shaking.
TABLE 5.1
DETERMINISTIC SITE PARAMETERS
Fault Name Distance from Site
(miles)
Maximum Eartliquake
Magnitude
Peak Site
Acceleration
Rose Canyon Fault Zone 5.2 7.2 0.37g
Newport-Inglewood 7.2 7.1 0.31g
Coronado Bank 21.2 7.6 0.18g
Elsinore-Temecula 24.0 6.8 O.lOg
Elsinore-Julian 24.0 7.1 0.20g
Elsinore-Glen Ivy 35.3 6.8 0.06g
The site could be subjected to moderate to severe ground shaking in the event of a major earthquake
on any of the above listed faults or other regional faults in the southem Califomia or northem Baja
Califomia area. Stmctures for the site should be constmcted in accordance with cunent UBC seismic
codes and local ordinances.
5.2 Liquefaction Potential
Liquefaction is a phenomenon in which loose, saturated and relatively cohesionless soil deposits lose
shear strength during strong ground motions. Primary factors controlling liquefaction include
intensity and duration of ground motion, characteristics of the subsurface soil, in situ stress
conditions, and depth to groundwater. Due to the very dense nature of the Point Loma Formation,
lack of a permanent shallow groundwater table and removal and recompaction of surficial deposits as
recommended hereinafter, the potential for liquefaction of the site subsoils is considered to be
very low.
Project No. 07238-42-01 •7-April 22, 2004
6. CONCLUSIONS AND RECOMMENDATIONS
6.1 General
6.1.1 No soil or geologic conditions were encountered during this and previous geoteclmical
studies that would preclude the development of the industrial subdivision as planned,
provided the recommendations of this report are followed.
6.1.2 Remedial grading to remove oversize debris fill, previously placed fill, topsoil, and
alluvium within planned areas of development will be required to properly compact
compressible surficial deposits to make the materials suitable for support of stmctural fill
and/or loading.
6.1.3 Recent trenching and drilling indicates that previously recommended buttresses on
proposed cut slopes in the Point Loma Formation are, in general, unnecessary. Exploration
at proposed cut slope locations encountered generally favorable geologic stmcture such as
dense horizontal or neutral to non-adverse bedding attitudes with respect to slope stability.
Localized adverse bedding planes and shallow bedding-plane-parallel shears, however, are
possible because of the undulating character of the bedding, as well as surficial slope creep
within highly weathered zones. Observation by an engineering geologist during grading is
recommended.
6.1.4 The oversize concrete-debris fill in Lots 2 and 3 require removal and replacement with
suitable fill within planned building pad areas. Complete removal will be required beneath
building pads. Stabilization of the proposed cut slope within this fill will be required with
limited removal and recompaction due to the probable extension of the fill beneath the
adjacent property to the south (see Cross Section D-D', Figure 10).
6.1.5 Nonrippable cemented concretion layers with thicknesses on the order of 12 inches were
encountered in the Point Loma Fonnation. The large concretions appear to be lens-shaped
and embedded in a rippable siltstone matrix. However, other hardrock may exist laterally
at different elevations. Oversize rock generated during excavations will require special
handling and placement in fills.
6.2 Seismic Design Criteria
6.2.1 The following table summarizes site-specific design criteria obtained from the 1997 UBC.
The values listed are for the Rose Canyon fault, which is identified as the nearest Type A
Project No. 07238-42-01 - 8 - April 22, 2004
fault and is more dominant that the nearest Type B fault due to its close proximity to
the site.
SEISMIC DESIGN PARAMETERS
Parameter Design Value UBC Reference
Seismic Zone Factor 0.4 Table 16-1
Soil Profile Type Sd Table 16-J
Seismic Coefficient, CA 0.44 Table 16-Q
Seismic Coefficient Cv 0.68 Table 16-R
Near Source Factor, Na 1.0 Table 16-S
Near Source Factor Ny 1.0 Table 16-T
Seismic Source B Table 16-U
6.3 Soil and Excavation Ciiaracteristics
6.3.1 The on-site surficial soils consist predominately of clayey silts, clays and interbedded
fine-grained, silty sands (undocumented fill, topsoil and alluvium). These materials
possess moderate to high expansion potential as defined by UBC Table 18-I-B.
6.3.2 Surficial deposits can be excavated using light to moderate effort with conventional heavy-
duty grading equipment. A moderate to heavy effort is anticipated to excavate dense Point
Loma Formation materials. Some zones will likely be encountered that require ripping
with a single-shank ripper on a D-9 or larger bulldozer.
6.3.3 Interpretation of data obtained from previous investigations and observations during our
recent update study suggest that rippable to marginally rippable conditions exist for most
areas of the site. Localized areas of hard concretions may require rock breaking. It is
recommended that breaking be performed such that the resulting broken materials are
generally 2 feet or less in maximum dimension in order to reduce the rock to a manageable
size for moving and placing in fill areas.
6.4 Grading
6.4.1 Grading should be performed in accordance with the Recommended Grading
Specifications contained in Appendix C. Where the recommendations of Appendix C
conflict with this section, the recommendations of this section take precedence.
Project No. 07238-42-01 •9-April 22, 2004
6.4.2 Prior to commencing grading, a preconstmction conference should be held at the site with
he owner or developer, grading contractor, civil engineer, and geotechnical engineer in
attendance. Special soil handling and/or the grading plans can be discussed at that time.
6.4.3 Site preparation should begin with removal of all deleterious material and vegetation. The
depth of removal should be such that soil exposed in cut areas or materials to be used as
fill are relatively free of organic material. Extensive gmbbing to remove stumps and roots
should be anticipated in areas of dense vegetation. Materials generated during clearing and
gmbbing should be exported from the site.
6.4.4 Undocumented fill, previously placed fill, topsoil, and alluvium within areas of planned
grading should be removed and recompacted. Surficial soil removals should extend at
least 10 feet horizontally beyond the edges of slopes or stmctural areas (i.e., building pads
and roadways). Dependent upon the conditions observed in the field, isolated areas of
deeper removals might be required.
6.4.5 Existing undocumented fill in the vicinity of the proposed cut slope at the southem end of
Lot 2 will require remedial grading to stabilize the slope. Remedial grading should consist
of excavating a 5-foot vertical at the property line and then a 1:1 slope projecting down to
the base of the undocumented fill. The slope should then be rebuilt back to planned design
grades with properly compacted fill. Figure 1 (Geologic Cross Section D-D') presents a
typical detail for the proposed stability fill.
6.4.6 After removal of compressible surficial soils as recommended above has been
accomplished, and prior to placing fill, the base of overexcavations should be scarified,
moisture conditioned, and compacted. Fill soils may then be placed and compacted to
design finish grade elevations. All fill, including scarified ground surfaces and backfill,
should be compacted to at least 90 percent of laboratory maximum dry density as
determined by ASTM D 1557-02, at or slightly above optimum moisture content. Fill areas
with in-place density results indicating moisture contents less than optimum will require
additional moisture conditioning prior to placing additional fill.
6.4.7 Oversize materials (rocks larger than 12 inches in maximum dimension) will be generated
during excavation of concretion zones and during remedial grading of undocumented fill.
Oversize rock and concrete chunks can be placed in fill areas in accordance with the
recommendations of Appendix C. It is recoimnended that oversize materials be kept at
least 10 feet below proposed finish grade in building pads and 2 feet below the deepest
utility within streets. This recommendation is intended to have a sufficient soil cap at
Project No. 07238-42-01 - 10 - April 22, 2004
grade to allow for future grading and installation of underground improvements without
encountering oversize materials. Asphalt concrete can be placed in fill provided it is kept
within proposed street right-of-ways and kept at least 5 feet below proposed subgrade
elevations.
6.4.8 Where practical, the upper 3 feet of all building pads (cut or fill) and 12 inches in
pavement areas should be composed of properly compacted or undisturbed formational low
to medium expansive soils (Expansion Index of 90 or less).
6.4.9 Import fill, if required, should consist of granular, low expansive (Expansion Index less
than 50) soil. Soil samples should be obtained from proposed borrow sites and subjected to
laboratory testing to verify they conform to the recommended expansion criteria.
6.5 Subdrains
6.5.1 Subdrains should be installed in the canyons to be filled. Typical subdrain installation
details are presented on Figure 17. Subdrains should extend up the canyons to
approximately 15 feet below proposed finish grade elevations and/or at least 2 feet below
any proposed utilities.
6.5.2 The lower 20 feet of subdrains exiting the base of compacted fill slopes should consist of
non-perforated pipe. A cutoff wall should be constmcted immediately below the junction
of the perforated pipe with the non-perforated pipe. The cut-off wall should extend at least
6 inches beyond the sides and the bottom of the subdrain trench and 6 inches above the top
of the pipe, as depicted on Figure 18.
6.5.3 Where subdrain systems do not outiet into permanent structures such as storm drains, the
outiet pipe should be provided with a concrete headwall, riprap, or similar device. A
typical subdrain outlet headwall detail is shown on Figure 19.
6.5.4 After installation of the subdrains, the project civil engineer should survey the locations
and prepare accurate as-built plans of the subdrain locations. The project geotechnical
engineer should verify the as-built subdrain outlet. The contractor should ensure that an
adequate drainage gradient is maintained throughout the system and that the subdrain
outlet is free of obstmctions.
Project No. 07238-42-01 - 11 - April 22, 2004
6.6 Slopes
6.6.1 Cut slopes excavated in dense Point Loma Formation or fill slopes comprised of the
on-site materials constructed at an inclination of 2:1 (horizontal:vertical) should be stable
to the planned heights. Slope stability analyses were perfonned for proposed cut and fill
slopes using SLOPEW, a computer program that calculates factors of safety using
conventional 2-dimensional slope stability equations. The analyses were based on direct
shear test results and the analyses indicate factors-of-safety against deep-seated instability
of at least 1.5. Results of the analyses are presented on Figures 8 through 12. A surficial
slope analysis was also performed and results indicate stable slope conditions (see
Figure 13).
6.6.2 The upper portion of the proposed cut slope depicted on Geologic Cross Section B-B' will
require constmction of a drained stability fill to mitigate the presence of a bedding plane
shear. The recommended limits of the stability fill are shown on the Figure 4. A typical
detail is shown on Figure 8.
6.6.3 Fill slopes should be overbuilt at least 3 feet horizontally and cut to the design finish
grade. As an altemative, fill slopes may be compacted by backrolling at vertical intervals
not to exceed 4 feet and then track-walking with a D-8 bulldozer or equivalent, such that
the soils are uniformly compacted to at least 90 percent to the face of tiie finish slope.
6.6.4 All slopes should be planted, drained and properly maintained to reduce erosion.
6.7 Foundations
6.7.1 Foundation recommendations presented herein are based on low to medium expansive (EI
less than 90) within 3 feet of ultimate finish pad grade placed and compacted in
accordance with the recommendations presented above.
6.7.2 Conventional continuous and/or isolated spread footings are suitable for support of typical
concrete tilt-up or masonry block industrial buildings. Continuous footings should be at
least 12 inches wide and 18 inches deep (below lowest adjacent grade). Isolated spread
footings should be at least 2 feet wide and extend 18 inches below lowest adjacent grade.
6.7.3 Continuous footings should be reinforced with four No. 4 steel reinforcing bars, two
placed near the top of the footing and two near the bottom. The project stmctural engineer
should design reinforcement for spread footings.
Project No. 07238-42-01 - 12 - April 22, 2004
6.7.4 Foundations proportioned as recommended may be designed for an allowable soil bearing
pressure of 2,000 psf (dead plus live loads). This bearing pressure may be increased by
300 psf and 500 psf for each additional foot of foundation width and depth, respectively,
up to a maximum allowable soil bearing pressure of 4,000 psf
6.7.5 The allowable soil bearing recommendations presented above are for dead plus live loads
only and may be increased by up to one third when considering transient loads such as
those due to wind or seismic forces.
6.7.6 Industiial building concrete slabs will likely be subjected to heavy loading from forklift
loading and/or storage of supplies. We recommend that the slab be designed by the
stmctural engineer to accommodate loading requirements. Based on soil conditions, we
recommend a minimum 5-inch thick concrete slab reinforced with No. 3 steel reinforcing
bars spaced 18 inches on center in both directions and placed at the slab midpoint. The
slab should be underlain by at least 4 inches of clean sand and where moisture sensitive
fioor coverings or slab moisture would be objectionable a visqueen moisture banier should
be placed in the middle of the sand blanket. If a stmctural section is required beneath the
slab to support forklift loading or to support cranes for lifting of tilt-up panels Class 2
aggregate base should be used in lieu of the clean sand beneath the slab.
6.7.7 Exterior concrete flatwork not subject to vehicular traffic should be at least 4 inches thick
and reinforced with 6x6-6/6 welded wire mesh. All concrete flatwork should be provided
with crack control joints to reduce and/or control shrinkage cracking. Control joint spacing
should be provided by the stmctural engineer based upon the slab thickness and intended
usage. Criteria of the American Concrete Institute (ACI) should be taken into
consideration when establishing crack control spacing. Prior to placing, the subgrade
should be compacted to at least 90 percent relative compaction at or slightiy above
optimum moisture content.
6.7.8 No special subgrade presaturation is deemed necessary prior to placing concrete; however,
the exposed foundation and slab subgrade soils should be sprinkled as necessary, to
maintain a moist soil condition as would be expected in any such concrete placement.
6.7.9 The recommendations of this report are intended to reduce tiie potential for cracking of
slabs due to expansive soils (if present), differential settiement of deep fills, or fills 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
Project No. 07238-42-01 - 13 - April 22, 2004
concrete shrinkage cracks is independent of the supporting soil characteristics. Their
occunence may be reduced and/or controlled by limiting the slump of the concrete, proper
concrete placement and curing, and the placement of crack-control joints at periodic
intervals, particularly where re-entrant slab comers occur.
6.8 Retaining Walls and Laterai Loads
6.8.1 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 30 pounds per cubic foot (pcf). Where the backfill will be inclined at no steeper than 2.0
to 1.0, an active soil pressure of 40 pcf is recommended. 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 less than 50. For those lots with
finish grade soils having an Expansion Index greater than 50 and/or where backfill
materials do not conform to the above criteria, Geocon Incorporated should be consulted
for additional recommendations.
6.8.2 Unrestrained walls are those that are allowed to rotate more than O.OOIH 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 active soil pressure presented above.
6.8.3 All 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. 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 less than 50) backfill material with no
hydrostatic forces or imposed surcharge load. If conditions different than those described
are anticipated, or if specific drainage details are desired, Geocon Incorporated should be
contacted for additional recommendations.
6.8.4 In general, wall foundations having a minimum depth and width of 1 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 less than 90. 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.
Project No. 07238-42-01 - 14 - April 22, 2004
6.8.5 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 at least 5 feet horizontally beyond the footing 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.
6.8.6 The recommendations presented above are generally applicable to the design of rigid
concrete or masonry retaining walls having a maximum height of 8 feet. In the event that
walls higher than 8 feet or other types of walls (such as crib-type walls) are planned,
Geocon Incorporated should be consulted for additional recommendations.
6.9 Slope Maintenance
6.9.1 Slopes that are steeper than 3:1 (horizontal:vertical) may, under conditions that are both
difficult to prevent and predict, be susceptible to near-surface (surficial) slope instability.
The instability is typically limited to the outer 3 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
occunence 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 recommended that, to
the maximum extent practical: (a) disturbed/loosened surficial soils be either removed or
properly recompacted, (b) inigation 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. 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 project's slopes in the future.
6.10 Drainage
6.10.1 Adequate drainage provisions are imperative. Under no circumstances should water be
allowed to pond adjacent to footings. The building pads should be properly finish graded
Project No. 07238-42-01 - 15 - April 22, 2004
after the buildings and other improvements are in place so that drainage water is directed
away from foundations, pavements, concrete slabs, and slope tops to controlled drainage
devices.
6.11 Grading Plan Review
6.11.1 The soil engineer and engineering geologist should review tiie grading plans prior to
finalization to verify their compliance with the recommendations of this report and
determine the necessity for additional analyses and/or recommendations.
Project No. 07238-42-01 - 16 - April 22, 2004
LIMITATIONS AND UNIFORMITY OF CONDITIONS
1. The recommendations of this report pertain only to the site investigated and are based upon
the assumption that the soil conditions do not deviate from those disclosed in the
investigation. If any variations or undesirable conditions are encountered during constmction,
or if the proposed constmction will differ from that anticipated herein, Geocon Incorporated
should be notified so that supplemental recommendations can be given. The evaluation or
identification of the potential presence of hazardous or conosive 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 information and recommendations contained herein are
brought to the attention of the architect and engineer for the project and incorporated into the
plans, and the necessary steps are taken to see that the contractor and subcontractors cany out
such recommendations in the field.
3. The findings of this report are valid as of the present date. However, changes in the conditions
of a property can occur with the passage of time, whether they are due to natural processes or
the works of man on this or adjacent properties. In addition, changes in applicable or
appropriate standards may occur, whether they result from legislation or the broadening of
knowledge. Accordingly, the findings of this report may be invalidated wholly or partially by
changes outside our control. Therefore, this report is subject to review and should not be
relied upon after a period of three years.
Project No. 07238-42-01 April 22, 2004
SOURCE: 2004 THOMAS BROTHERS MAP
SAN DIEGO COUNTY, CALIFORNIA
REPRODUCED WITH PERMISSION GRANTED BY THOMAS BORTHERS MAPS.
THIS MAP IS COPYRIGHT BY THOKIIAS BROS. MAPS. fT IS UNLAWFUL TO COPY
OR REPRODUCE Aa OR ANY PART THEREOF, WHETHER FOR PERSONAL USE OR
RESALE, WITHOUT PERMISSION.
M
NO SCALE
GEOCON
INCORPORATED
GEOTECHNICAL CONSULTANTS
6960 FLANDERS DRIVE - SAN DIEGO, CALIFORNIA 92121 - 2974
PHONE 858 558-6900 - FAX 858 558-6159
GC/MM DSK/EOOOO
VICINITY MAP
CARLSBAD TRACT CT-00-20
CARLSBAD, CALIFORNIA
DATE 04-22-2004 PROJECTNO. 07238-42-01 FIG. 1
Mico»la/TamplarM/TamplalM/G«»tMh/Vidni(y Map
A
320—1
300-
280-
z
o
< 260-
>
Ul
_j
lij
240 —
220-
200-
PROPOSED
SLOPE
Kpl
40
A'
r-320
-300
-280
-260
-240
-220
-200
z o
I-< >
Ul
80 120 160 200
DISTANCE
240 280 320 360 380
GEOLOGIC CROSS-SECTION A-A^
SCALE: 1" = 40' (Vert. = Horiz.)
CARLSBAD TRACT CT-00-20
CARLSBAD, CALIFORNIA
GEOCON
INCORPORATED GEOTKHNICAL CONSULTANTS
6960 FLANDKS DRIVE - SAN DIEGO, CAUFORNIA 92121 - 2974
PHONE 858 558-6900 - FAX 858 558-6159
PROJECT NO. 07238 - 42 - 01
FIGURE 7
DATE 04-22-2004
E/2004/7038_XSAA.DWG/oml
B
320—1
300-
z o
< 280->
Ul _i
Ul
260-
240—1
CARLSBAD TRACT CT-00-20
CARLSBAD, CALIFORNIA
EXISTING
SLOPE •
?-jr'-xxxxxxxxxxxx xxxxxxxxxxx xxxxxxxxxxxxxxxxxxxxxx xxxxxxxxxxxx xxxxxx
7XXXXXXXXXXXXX XXXXXXXXXXXXXXXX XXXXX xxxxxx y.T^J.'<T>, %f.Tf,y. XXXX
^'•'^ fy'''^^ PROPOSEI
XXXXXX X Xj^^^^^^^X XXXXXX
-7'^
XXXXX XX
xxxxxxxxxxxxxxxxxxxx
PROPOSED STABIUTY FILL
xxxxxxxx
—Tynncy
-Kpl— — .—-STL LZ^- —— —— Kpl-—--
-JTX'XTXX X X X xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
CEMENTED LAYERS
(PROJECTED)
xxxxxxxxxxxxxxxxxxxxxxxxx
Kpl
40 80 120 160 200 240
DISTANCE
280 320 360 400 440 480
GEOLOGIC CROSS-SECTION B-B^
SCALE: r = 40' (Vert. = Horiz.)
B'
-320
-300
z o
(-
-280 5
Ul
_l
Ul
— 260
-240
GEOCON
INCORPORATED GEOTECHNICAL CONSULTANTS
6960 FUNDBIS DRIVE • SAN DIEGO, CAUBDRNA 92121 - 2974
PHONE 858 558-6900 - FAX 858 558-6159
PROJECT NO. 07238 - 42 - 01
FIGURE 8
DATE 04 - 22 - 2004
E/200.4/7038 XSBB.DWG/aitil
320-
300-
< 280 H >
260-
240-"
EXISTING
SLOPE
,x xxxxxxxxxxxx X x.i^ --— -T;;^ "y
XX x^>rx^x XXX XXXXX7X XXX XX xxxxxxxx
" / FAULT^ v^i^
EMENJED LAYERS^
Ixxxxxxxxxx
7x xxxxxxxxxxxx X /^^°^S^xx7xxxxxxxxxV^xxxxxxxxxxxi
X X X X « Xi*-^' "
•NEW PROPOSED STABUTrFILL
xxxxxxxxxxxxxxx
Kpt
xxxxxxxxxxxxx
c
1—320
— 300
-280 < >
Ul
_l
Ul
-260
"—240
40 80 120
DISTANCE
160 200 240
GEOLOGIC CROSS-SECTION C-C
SCALE: 1" = 40' (Vert. = Horiz.)
CARLSBAD TRACT CT-0a20
CARLSBAD, CALIFORNIA
GEOCON
INCORPORATED GEOTECHNICAL CONSULTANTS
6960 FLANDERS DRIVE - SAN DIEGO, CAUFORNIA 92121 - 2974
PHOSE 858 558-6900 - FAX 858 558-6159
PROJEa NO. 07238 - 42 - 01
FIGURE 9
DATE 04-22-2004
E:/2004/7038_XSCCDWG/oirJ
D
320-
300-
280-
< 260 H >
UJ
Ul
240-
220-
T-14
EXISTING
GRADE —V PROPOSED
\ GRADE -V
\ A T-
f
13
t
T:
NEW PROPOSED J
STABILrrY FILL '— TOPSOIL
Kpl Kpl
40
I
80 120 160 200
D'
1-320
-300
-280
-260 < >
Ul
UJ
— 240
1—220
DISTANCE
GEOLOGIC CROSS-SECTION D-D^
SCALE: 1" = 40' (Vert. = Horiz.)
CARLSBAD TRACT CT-0a20
CARLSBAD, CALIFORNIA
GEOCON
INCORPORATED GEOTECHNICAL CONSULTANTS
6960 FLANDKS DRIVE - SAN DIEGO, CAURDRNIA 92121 - 2974
PHONE 858 558-6900 - FAX 858 558-6159
PROJECT NO. 07238 - 42 - 01
FIGURE 10
DATE 04-22-2004
E:/2004/7038.XSOCX)WG/aml
Project No. 07238-42-01
Saved Date: 4/22/2004
CARLSBAD TRACT GT 00-20
CARLSBAD, CALIFORNIA
SECTION A-A'
3.456. / / / /
320
300
— ^280
260
— 240
220
100 120 140 160 180
Distance (feet)
200 220 240 260 280 300
Soil Type Unit Weight
(pcf)
Angle of Internal
Friction (deg)
Cohesion
(psf)
Qcf 130 30 400
Kpl 130 30 700
File Name: Carlsbad Tract\A-A(1).slz Figure 11
Project No. 07238-42-01
Saved Date: 4/22/2004
CARLSBAD TRACT CT 00-20
CARLSBAD, CALIFORNIA
SECTION B-B'
2.181
20 40 60 80 100 120 140 160 180
Distance (feet)
200 220 260 280
Soil Type Unit Weight
(pcf)
Angle of Internal
Friction (deg)
Cohesion
(psf)
Qpf 130 30 200
Kpl 130 30 700
B.P.S. 130 10 100
File Name : Carlsbad Tract\B-B(1).slz Figure 12
Project No. 07238-42-01
Saved Date: 4/22/2004 CARLSBAD TRACT CT 00-20
CARLSBAD, CALIFORNIA
SECTION B-B'
2.590
320
300
280
0) 0)
c o
^ 260
Oi
LU
240
220
320
300
— 280
20 40 60 80 120 140 160 180
Distance (feet)
260 280
Soil Type Unit Weight
(pcf)
Angle of Internal
Friction (deg)
Cohesion
(psf)
Qpf 130 30 200
Kpl 130 30 700
B.P.S. 130 10 100
Qcf 130 30 400
File Name: Carlsbad Tract\B-B(2).sl2
Figure 13
Project No. 07238-42-01
Saved Date: 4/22/2004
CARLSBAD TRACT CT 00-20
CARLSBAD, CALIFORNIA
SECTION C-C
1.937
320 I— 320
300
— 280
— 260
— 240
60 80 100 120 140 160 180
Distance (feet)
220
200 220 240 260 280 300
Soil Type Unit Weight
(pcf)
Angle of Internal
Friction (deg)
Cohesion
(psf)
Kpl 130 30 700
B.P.S. 130 10 100
Fault 130 10 100
File Name : Carlsbad Tracl\C-C(1).slz
Figure 14
Project No. 07238-42-01
Saved Date: 4/22/2004
CARLSBAD TRACT CT 00-20
CARLSBAD, CALIFORNIA
SECTION C-C
2.801
320
300
280
CD
c o
^ 260
0)
LU
240
220
—1 320
300
— 280
20 40 60 80 100 120 140 160 180
Distance (feet)
260 280
Soil Type Unit Weight
(pcf)
Angle of Internal
Friction (deg)
Cohesion
(psf)
Kpl 130 30 700
B.P.S. 130 10 100
Fault 130 10 100
Qcf 130 30 400
File Name: Carlsbad Tracl\C<;(2).slz
Figure 15
ASSUMED CONDITIONS
SLOPE HEIGHT H = Infinite
DEPTH OF SATUFJATION Z = 3 feet
SLOPE INCLINATION 2:1 (Horizontal : Vertical)
SLOPE ANGLE i = 26.6 degrees
UNIT WEIGHT OF WATER = 62.4 pounds per cubic foot
TOTAL UNIT WEIGHT OF SOIL 7, = 130 pounds per cubic foot
ANGLE OF INTERNAL FRICTION <f> = 30 degrees
APPARENT COHESION C = 200 pounds per square foot
SLOPE SATURATED TO VERTICAL DEPTH Z BELOW SLOPE FACE
SEEPAGE FORCES PARALLEL TO SLOPE FACE
ANALYSIS :
FS = C + (7f -Jw) Z cos' i tan ^
7; 2 sin i cos i
= 1.88
REFERENCES:
1 Haefell, R. The Stability of Slopes Acted Upon by ParaUel Seepage, Proc.
Second International Conference, SMFE, Rotterdam, 1948,1, 57-62
2 Skempton, A. W., and FA. Delory, Stability of Natural Slopes in London Clay, Proc.
Fourth International Conference, SMFE, London, 1957, 2, 378-81
SURFICIAL SLOPE STABILITY ANALYSIS
GEOCON
INCORPORATED Q
GEOTECHNICAL CONSULTANTS
6960 FLANDERS DRIVE - SAN DIEGO, CALIFORNIA 92121 - 2974
PHONE 858 558-6900 - FAX 858 558-6159
JB/AML DSK/EOOOO
CARLSBAD TRACT CT-00-20
CARLSBAD, CALIFORNIA
DATE 04 - 22 - 2004 PROJECT NO. 07238 - 42 - 01 FIG. 16
COlIOOT2.DWG/inJ
APPROVED
'FILTER FABRIC
1" MAX. OPEN-GRADED
AGGREGATE 9 CUBIC FT7FT.
MINIMUM
NOTES:
1 SUBDRAIN PIPE SHOULD BE 6-INCH MINIMUM DIAMETER, PERFORATED, THICK WALLED SCHEDULED
40 PVC, SLOPED TO DRAIN AT 1 PERCENT MINIMUM AND CONNECTED TO STORM DRAIN SYSTEM OR
APPROVED OUTLET.
2 WHEN SUBDRAIN PIPE EXCEEDS 500 FEET, PIPE DIAMETER SHOULD BE INCREASED TO 8 INCHES.
3 FILTER FABRIC TO BE MIRAFI 140N OR EQUIVALENT.
TYPICAL SUBDRAIN DETAIL
GEOCON
INCORPORATED a GEOTECHNICAL CONSULTANTS
6960 FLINDERS DRIVE - SAN DIEGO, CALIRDRNIA 92121 - 2974
PHONE 858 558-6900 - FAX 858 558-6159
JB/AML DSK/EOOOO
CARLSBAD TRACT CT-00-20
CARLSBAD, CALIFORNIA
DATE 04 - 22-2004 PROJECT NO. 06195 - 12 - 01 FIG. 17
E/CeOTECH/TYP/rSD/oml
FRONT VIEW
I- 6" MIN.
CONCRETE
CUT-OFF WALL
6" MIN.
6" MIN.
NO SCALE
SIDE VIEW
12"
MIN.
CONCRETE _
CUT-OFF WAU
S.:..'.—_'..
6" MIN. fTYP)
^ SOLID SUBDRAIN PIPE PERFORATED SUBDRAIN p'pE ' U • • • • • • Y
-•—r——27"
. •' a- • . • ^^^^ 6" MIN. (TYP) A\ AN /
NO SCALE
RECOMMENDED SUBDRAIN CUT-OFF WALL
GEOCON
INCORPORATED Q
GEOTECHNICAL CONSULTANTS
6960 FLANDERS DRIVE - SAN DIEGO, CALIRDRNIA 92121 - 2974
PHONE 858 558-6900 - FAX 858 558-6159
JB/AML DSK/EOOOO
CARLSBAD TRACT CT-00-20
CARLSBAD, CALIFORNIA
DATE 04 - 22-2004 PROJECT NO. 07238 - 42 - 01 FIG. 18
FRONT VIEW
SUBDRAIN
4 :
18"
12"
SIDE VIEW
SUBDRAIN
CONCRETE
HEADWAU
NOTE: HEADWALL SHOULD OUTLET AT TOE OF FILL SLOPE
OR INTO CONTROLLED SURFACE DRAINAGE
NO SCALE
NO SCALE
SUBDRAIN OUTLET HEADWALL DETAIL
GEOCON
INCORPORATED Q
GEOTECHNICAL CONSULTANTS
6960 FLANDERS DRIVE - SAN DIEGO, CALIRDRNIA 92121 - 2974
PHONE 858 558-6900 - FAX 858 558-6159
JB/AML DSK/EOOOO
CARLSBAD TRACT CT-00-20
CARLSBAD, CALIFORNIA
DATE 04 - 22 - 2004 PROJECT NO. 07238 - 42 - 01 FIG. 19
E/m>/S0HD.tWG/oiJ
APPENDIX M A
APPENDIX A
FIELD INVESTIGATION
The field mvestigation was performed between March 29 and April 3, 2004, and consisted of a site
reconnaissance, geologic field mapping, and excavation of 14 exploratory backhoe trenches and one
large-diameter boring. Trenches were excavated using a John Deere JD450 track mounted backhoe
equipped with a 24-inch-wide rock bucket. During trenching, chunk samples and disturbed bulk
samples were obtained for laboratory testing. The large diameter boring was drilled using an EZ
Bore-100 truck mounted drill rig equipped with a 30-inch diameter bucket auger. During Drilling,
relatively undisturbed soil samples were obtained by driving a 2.5-inch O.D., split-spoon sampler 12
inches into the undisturbed soil mass using a Kelly Bar. The sampler was equipped with 2-3/8-inch
diameter brass sampler rings to facilitate laboratory testing.
Soil conditions encountered in the boring and trench excavations were visually examined, classified,
and logged in general accordance with American Society for Testing and Materials (ASTM) practice
for Description and Identification of Soils (Visual-Manual Procedure D 2844). Logs of the boring
and trenches are presented on Figures A-1 through A-16. The logs depict the soil and geologic
conditions encountered and the depth at which samples were obtained. The approximate locations of
the exploratory excavations are shown on the Geologic Map (Figiu-e 2, map pocket).
Exploratory excavations (borings and trenches) pertinent to the new Tentative Map from previous
geotechnical investigations have also been included herewith. The logs are presented to provide
additional subsurface information regarding the depths and types of materials that were encountered
on site.
Project No. 07238-42-01 April 22, 2004
PROJECT NO. 07238-42-01
SAMPLE
NO.
SOIL
CLASS
(USCS)
BORING B 1
ELEV. (MSL) _
EQUIPMENT
310 DATE COMPLETED 03-29-2004
EZ BORE 100
Q o h
S HI m >- =-a:
Q
5 O
o
- 0
- 6
2 -
4 -
8 -
10 -
12
- 14
16
18 -
20 -
- 22 -
- 24
- 26 -
- 28
Bl-3
SC
ML-CL
MATERIAL DESCRIPTION
PREVIOUSLY PLACED FILL
3 inches Asphalt Concrete paving and 12 inch Base
Loose to medium dense, dry to humid, light to medium yellow brown.
Gravelly. Clayey, fine SAND: with some silt
POINT LOMA FORMATION
Hard, damp, medium yellow-brown-olive, very Silty CLAYSTONE; blocky,
massive to low-angle dipping beds, weathered
-Becomes more hard, less weathered at 7 feet
-Bedding N40W, 3SW (thin, 1" cemented layer)
-Fault N38W, 50SW with approx. 1/8-inch calcium carbonate lining; fault
offsets cemented layer approx. 3"
-BEDDING PLANE SHEAR (BPS) at 16.5 feet, N9W, 7SW, V,-'A inch
thick plastic, wet, remolded clay; through-going at top of 3" cemented layer
108.4 18.6
8/6"
-Bedding NlOE, 6NW (cemented layer thick)
-Gypsum veinlets
-Cemented zone 2-3" thick
Figure A-1, 07238-42^)1.GP.
Log of Boring B 1, Page 1 of 2
SAMPLE SYMBOLS ^ ' """"'"^ "•^^"'^^^SSFUL B ... STANDARD PENETRATION TEST 1 ... DRIVE SAMPLE (UNDISTURBED)
^ ... DISTURBED OR BAG SAMPLE B ... CHUNK SAMPLE I ... 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.
PROJECT NO. 07238-42-01
DEPTH
IN
FEET
SOIL
CLASS
(USCS)
BORING B 1
ELEV. (MSL.) _
EQUIPMENT
310 DATE COMPLETED 03-29-2004
EZBORE 100
pi ll
Q
1^
: o o
- 30 MATERIAL DESCRIPTION
Bl-6
32 -
34 -
-se-
as -
- 40
42 -
- 44
46 -
48
- 50
- 52
- 54 -
Very hard, damp, dark gray-olive, very Silty CLAYSTONE; with interbedded
yellowish to reddish brown, sandy siltstone layers, little or no fracturing or
jointing and massive to low-angle dipping bedding
9/6" 105.3 19.1
Bl-7
Bl-8
ML-CL
10/6" 106.9 n.7
-44'-50' (moist to wet surfaces along bedding planes)
BI-9
ML
-Cemented zone 6" to 10" thick (coring bucket used to penetrate)
Very hard, damp to moist, dark gray-olive, very Clayey SILTSTONE; massive
to low-dipping bedding as above
17/6"
BORING TERMINATED AT 55 FEET
Figure A-1, 07238.42^51. GP.
Log of Boring B 1, Page 2 of 2
SAMPLESYMBOLS ••• SAMPLING UNSUCCESSFUL B ... STANDARD PENETRATION TEST 1 ... DRIVE SAMPLE (UNDISTURBED)
^ ... DISTURBED OR BAG SAMPLE K ... 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.
PROJECT NO. 07238-42-01
DEPTH
IN
FEET
SAMPLE
NO.
>-O O —I o X I-
SOIL
CLASS
(USCS)
TRENCH T 1
ELEV. (MSL.)
EQUIPMENT
296 DATE COMPLETED 03-31-2004
JD450
i t- w >
Z u-
a:
Q
O z 5 O o
MATERIAL DESCRIPTION
- 2
- 4
CL
TOPSOIL
Soft, very moist, dark yellow brown, Sandy, Silty CLAY; very porous,
burrows, roots
-Irregular contact
CL
POINT LOMA FORMATION
Very stiff to hard, moist, dark olive-yellow brown, Silty CLAYSTONE;
weathered, fractured, with interbedded thin, cemented layers
-Bedding N32W, 6SW
-Becomes hard at approx. 6.5 feet
TRENCH TERMINATED AT 8 FEET
Figure A-2, 07238-42^)1.GPJ
Log of Trench T 1, Page 1 of 1
. . .r,. - ^v,. .r,^. n •• SAMPLING UNSUCCESSFUL
SAMPLE SYMBOLS
B •• STANDARD PENETRATION TEST 1 ... DRIVE SAMPLE (UNDISTURBED)
^ ... DISTURBED OR BAG SAMPLE B ... CHUNK SAMPLE Y ... 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.
PROJECT NO. 07238-42-01
DEPTH
IN
FEET
SAMPLE
NO.
SOIL
CLASS
(USCS)
TRENCHT 2
ELEV. (MSL.) 298
EQUIPMENT
DATE COMPLETED
JD450
03-31-2004
r=i
2 O !-
I- w g
QL
Z Ll.
o
LU 3^
oz s o o
MATERIAL DESCRIPTION
- 2 -
- 4
- 6 -
- 8
CL
TOPSOIL
Soft to stiff, very moist, dark brovm-olive, Silty, Sandy CLAY; porous, with
roots, shrinkage cracks
CL
POINT LOMA FORMATION
Hard, moist, medium to dark olive-brown, Silty CLAYSTONE; laminated
bedding N60W, 2SW
-3" thick cemented layer
TRENCH TERMINATED AT 8 FEET
Figure A-3, 07238-42-01.GPJ
Log of Trench T 2, Page 1 of 1
SAMPLE SYMBOLS ° -E ... STANDARD PENETRATION TEST 1 ... DRIVE SAMPLE (UNDISTURBED)
^ ... DISTURBED OR BAG SAMPLE Ei] ... CHUNK SAMPLE I ... 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.
PROJECTNO. 07238-42-01
DEPTH
IN
FEET
SAMPLE
NO.
SOIL
CLASS
(USCS)
TRENCH T 3
ELEV. (MSL.) 295
EQUIPMENT
DATE COMPLETED 03-31-2004
JD450
?=: UJ 2 O h 2 t
, w >
Z U-
o
«^
O Z 5 O O
- 0
- 2
- 4 -
- 6 -
- 8 -
MATERIAL DESCRIPTION
UNDOCUMENTED FILL
Loose, moist, light to dark brown (mottled), Gravelly, Clayey SAND; wood,
plastic, oversize concrete chunks
SC
CL
POINT LOMA FORMATION
Soft, moist, dark brown-olive, Silty CLAY; very weathered, claystone,
fractured, creep layers approx. 5-10 degrees out of slope
Hard, moist, medium to dark olive, Silty CLAYSTONE; bedding approx.
horizontal
CL
TRENCH TERMINATED AT 9'/2 FEET
Figure A-4, 07238-42-01.GPJ
Log of Trench T 3, Page 1 of 1
SAMPLE SYMBOLS ° ' • ^^^''^''^s UNSUCCESSFUL B ... STANDARD PENETRATION TEST 1 ... DRIVE SAMPLE (UNDISTURBED)
^ ... DISTURBED OR BAG SAMPLE liil ... CHUNK SAMPLE I ... 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.
PROJECT NO. 07238-42-01
DEPTH
IN
FEET
SAMPLE
NO.
SOIL
CLASS
(USCS)
TRENCH T 4
ELEV. (MSL.) 275
EQUIPMENT
DATE COMPLETED 03-31-2004
JD450
?s UJ ^
b z t
I- CO >
Z U-
Q:: o
WUJ o i 2 o o
- 0 MATERIAL DESCRIPTION
2 -
- 4 -
T4-1
T4-2
6 -
TOPSOIL
Stiff, moist, dark brown, Silty CLAY; very porous, roots, burrows
CL
POINT LOMA FORMATION
Hard, moist, medium olive-brown, Silty CLAYSTONE; horizontally bedded,
laminated
CL
TRENCH TERMINATED AT 7 FEET
Figure A-5, 07238-42^)1.GPJ
Log of Trench T 4, Page 1 of 1
SAMPLE SYMBOLS ° • '^''''''^ UNSUCCESSFUL B ... STANDARD PENETRATION TEST 1 ... DRIVE SAMPLE (UNDISTURBED)
^ ... DISTURBED OR BAG SAMPLE B ... CHUNK SAMPLE I ... 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. INDICATED. IT
PROJECT NO. 07238-42-01
DEPTH
IN
FEET
SAMPLE
NO.
SOIL
CLASS
(USCS)
TRENCHT 5
ELEV. (MSL.) 278
EQUIPMENT
DATE COMPLETED 03-31-2004
JD450
I- w g
Z U. ll
BC
a
LU 1^ OT jfJ
OZ 5 O O
MATERIAL DESCRIPTION
- 2
- 4 -
6 -
- 8 -
- 10
- 12
- 14
SC-CL TOPSOIL
Loose, damp, dark brown. Clayey, fine SAND; very porous, roots
POINT LOMA FORMATION
Hard to very hard, damp, medium olive brown, very Silty CLAYSTONE to
Clayey SILTSTONE; discontinuous, blocky, fracturing
CL-ML
-Fossil clam shell (1cm x 2cm mold) in calcium-carbonate cemented layer
approx. 2" thick; horizontal bedding
TRENCH TERMINATED AT 14 FEET
Figure A-6, 07238-42-01.GPJ
Log of Trench T 5, Page 1 of 1
SAMPLE SYMBOLS ° - """"""^ UNSUCCESSFUL B ... STANDARD PENETRATION TEST 1 ... DRIVE SAMPLE (UNDISTURBED)
^ ... DISTURBED OR BAG SAMPLE B ... CHUNK SAMPLE I ... 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.
PROJECT NO. 07238-42-01
DEPTH
IN
FEET
SAMPLE
NO.
>• O
o
_l
o
X h-
SOIL
CLASS
(USCS)
TRENCH T 6
ELEV. (MSL.) 261
EQUIPMENT
DATE COMPLETED 03-31-2004
JD450
I- w g
D.
OT ^ 2 u.
DC Q
UJ
o z
^8
MATERIAL DESCRIPTION
2 -
T6-1
T6-2
CL
- 6
TOPSOIL
Soft, moist, dark brown, Silty CLAY
ML
POINT LOMA FORMATION
Very hard, damp, light yellow-brown-olive. Clayey SILTSTONE; with thin
fine sandstone layers
-Bedding horizontal
108.9 17.7
TRENCH TERMINATED AT 7 FEET (Near Refiisal)
Figure A-7,
Log of Trench T 6, Page 1 of 1
07238-42-01.GPJ
SAMPLE SYMBOLS n ... SAMPLING UNSUCCESSFUL B ... STANDARD PENETRATION TEST • . . DRIVE SAMPLE (UNDISTURBED)
^ ... DISTURBED OR BAG SAMPLE B ... CHUNK SAMPLE I . . 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.
PROJECTNO. 07238-42-01
DEPTH
IN
FEET
SAMPLE
NO.
SOIL
CLASS
(USCS)
TRENCH T 7
ELEV. (MSL.) 282
EQUIPMENT
DATE COMPLETED 03-31-2004
JD 450
2 o I-t 2 y.
H- OT >
^OTO
OT -r-Z U.
u
cc a
O 2 5 O O
- 0 MATERIAL DESCRIPTION
- 2 -
- 4 -
- 6 -
- 8 -
CL TOPSOIL
Soft, moist, dark brown, Silty CLAY; porous, roots
POINT LOMA FORMATION
Hard, damp, dark olive-brown, very Silty CLAYSTONE;
-4" thick, dense, light brown, silty, fine sandstone layer; horizontal
CL-ML
ML Very hard, damp, medium olive. Clayey SILTSTONE
-Cemented concretions layer (refiisal)
TRENCH TERMINATED AT 814 FEET (Refiisal)
Figure A-8, 07238-42-01.GPJ
Log of Trench T 7, Page 1 of 1
SAMPLE SYMBOLS ° • UNSUCCESSFUL B ... STANDARD PENETRATION TEST 1 ... DRIVE SAMPLE (UNDISTURBED)
S ... DISTURBED OR BAG SAMPLE i] ... CHUNK SAMPLE I ... WATER TABLE OR SEEPAGE
i^MnT w?BplMT=Vf^;^ oii™ "^"^"N ^''P'-'ES 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.
PROJECT NO. 07238-42-01
DEPTH
IN
FEET
SAMPLE
NO.
>-O
o
_l o X
SOIL
CLASS
(USCS)
TRENCH T 8
ELEV. (MSL.) 270
EQUIPMENT
DATE COMPLETED 03-31-2004
JD450
o ^
« k
I^IOTQ
W -:• Z u.
ll
CC
a
gi
oz
2 O O
- 0 MATERIAL DESCRIPTION
- 2 -
- A -
- 6 -
CL
TOPSOIL
Soft, very moist, dark brown, Silty CLAY; porous, roots
POINT LOMA FORMATION
Very hard, damp, medium olive, very Silty CLAYSTONE; blocky to massive
CL
SM
-Contact is approx. horizontal
Very dense, damp, light brovyn to tan, very Silty, very fine SANDSTONE"
TRENCH TERMINATED AT 6'/7 FEET
Figure A-9, 07238-42-01.GPJ
Log of Trench T 8, Page 1 of 1
SAMPLE SYMBOLS ° ' UNSUCCESSFUL B - STANDARD PENETRATION TEST 1 ... DRIVE SAMPLE (UNDISTURBED)
^ ... DISTURBED OR BAG SAMPLE B ... CHUNK SAMPLE I ... 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.
PROJECTNO. 07238-42-01
DEPTH
IN
FEET
SAMPLE
NO.
SOIL
CLASS
(USCS)
TRENCH T 9
ELEV. (MSL.) 282
EQUIPMENT
DATE COMPLETED 03-31-2004
JD450
h- W g
OT ^ z u. go
>- —
Q
LU S~ °^ U ?2
OT[JJ
O Z
2 O
O
MATERIAL DESCRIPTION
- 2 -
- 4 -
- 6
- 8
CL
TOPSOIL
Soft, moist, dark brovm, Silty CLAY; porous, roots
POINT LOMA FORMATION
Stiff to very stiff, moist, medium olive, Silty CLAYSTONE; very weathered
and fractured
CL
-Contact is approx. horizontal
Hard, damp, medium olive, Silty CLAYSTONE; blocky, less^actured'
CL
TRENCH TERMINATED AT 8 FEET
Figure A-10, 1 1 1 •
07238-42-01.GPJ
Log of Trench T 9, Page 1 of 1
SAMPLE SYMBOLS ° - UNSUCCESSFUL B ... STANDARD PENETRATION TEST 1 ... DRIVE SAMPLE (UNDISTURBED)
^ ... DISTURBED OR BAG SAMPLE K ... CHUNK SAMPLE I ... 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. «' ' DATE INDICATED. IT
PROJECT NO. 07238-42-01
DEPTH
IN
FEET
SAMPLE
NO.
>-o o
_l o X
SOIL
CLASS
(USCS)
TRENCH T 10
ELEV. (MSL.) 278
EQUIPMENT
DATE COMPLETED 03-31-2004
JD450
2 o f-
h- Z U.
I- w >
^ w2
w
2 u-
ll
OC
Q
OZ
2 O O
- 0 MATERIAL DESCRIPTION
- 2 -
- 4
- 6
TlO-1
TOPSOIL
Soft, very moist, dark brown, Silty CLAY; porous, roots
CL
CL
POINT LOMA FORMATION
Hard, very moist, medium brown, Silty CLAYSTONE; very weathered,
fractured
-Horizontal contact
Very hard, moist, medium to dark olive-brown, very Silty CLAYSTONE
ML-CL
TRENCH TERMINATED AT 6V2 FEET
Figure A-11, 07238-42.01 .GPJ
Log of Trench TIO, Page 1 of 1
SAMPLE SYMBOLS ° • UNSUCCESSFUL B ... STANDARD PENETRATION TEST 1 ... DRIVE SAMPLE (UNDISTURBED)
S ... DISTURBED OR BAG SAMPLE B ... CHUNK SAMPLE I ... 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
PROJECTNO. 07238-42-01
SAMPLE
NO.
SOIL
CLASS
(USCS)
TRENCH Til
ELEV. (MSL.) 305
EQUIPMENT
DATE COMPLETED 04-03-2004
CASE 310
Suj-^
h- OT g
OT -> Z U.
o
UJ
li
Oz 20 o
- 0 MATERIAL DESCRIPTION
- 2 -
- 4 -
- 6 -
Tll-1
GM
2 inches ASPHALT CONCRETE and BASE
UNDOCUMENTED FILL
Medium dense, dry, light reddish brown to brown. Sandv. fine GRAVEL
TOPSOIL TOPSOIL
Stiff, very moist, dark brown, Silty CLAY
CL
CL-ML
POINT LOMA FORMATION
Hard, moist, medium olive-brown, very Silty CLAYSTONE to Clayey
SILTSTONE
-Bedding N25W, 5SW to horizontal (undulating)
1070 20.1
TRENCH TERMINATED AT IVi FEET
Figure A-12, 07238-42-01.GPJ
Log of Trench Til, Page 1 of 1
SAMPLE SYMBOLS ° •UNSUCCESSFUL B ... STANDARD PENETRATION TEST 1 ... DRIVE SAMPLE (UNDISTURBED)
M ... DISTURBED OR BAG SAMPLE iki ... CHUNK SAMPLE I ... 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.
PROJECT NO. 07238-42-01
DEPTH
IN
FEET
SAMPLE
NO.
>-O O
—1
o
X
SOIL
CLASS
(USCS)
TRENCH T 12
ELEV. (MSL.) 308
EQUIPMENT
DATE COMPLETED
CASE 310
04-03-2004
; UJ ^ '" h
OT g
OT2
W
2 u-°£
CC
o
UJ ^
li
W If]
02 2 O
o
- 0
- 2
MATERIAL DESCRIPTION
ASPHALT CONCRETE and BASE
SC UNDOCUMENTED FILL
Medium dense, moist, medium brovyn (mottled). Clayey SAND
CL-ML
POINT LOMA FORMATION
Very stiff, very moist, light yellowish brown to olive, very Silty
CLAYSTONE
-N15E, lONW along orange oxidized silt layer
Very hard, moist, medium to light olive, very Silty CLAYSTONE to Clayey
SILTSTONE
CL-ML
TRENCH TERMINATED AT 6 FEET
Figure A-13, 0723B-42-01.GPJ
Log of Trench T 12, Page 1 of 1
SAMPLE SYMBOLS ° • UNSUCCESSFUL B ... STANDARD PENETRATION TEST 1 ... DRIVE SAMPLE (UNDISTURBED)
S ... DISTURBED OR BAG SAMPLE B ... CHUNK SAMPLE I ... 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.
PROJECT NO. 07238-42-01
DEPTH
IN
FEET
SAMPLE
NO.
>-CJ
o
—I o X
I-
SOIL
CLASS
(USCS)
TRENCHT 13
ELEV. (MSL.) 303
EQUIPMENT
DATE COMPLETED 04-03-2004
CASE 310
o "J
I- OT g UJ rn Q OT
SB
OT
2 u, ll OC
o
W UJ
O 2 2 O
O
MATERIAL DESCRIPTION
- 2 -
- 4
- 8
- 10 -
- 12 -
- 14 -
- 16 -
/i
/
/
/
A
O//
UNDOCUMENTED FILL
Loose, moist, dark to light brovm (mottled). Clayey, very coarse GRAVEL;
very porous, debris fill consisting of oversize 1-5' diameter concrete chunks
(curb, pavement) and wood, plastic and asphalt concrete chunks
GC
SC TOPSOIL
Loose, very moist to wet, dark gray-brovra. Clayey, Gravelly SAND; with
chunks of Point Loma Formation
TRENCH TERMINATED AT 17 FEET (Refiisal On Concrete Debris In
Sidewalls)
Figure A-14, 07238-42-01.GPJ
Log of Trench T 13, Page 1 of 1
SAMPLE SYMBOLS ° UNSUCCESSFUL B ... STANDARD PENETRATION TEST 1 ... DRIVE SAMPLE (UNDISTURBED)
^ ... DISTURBED OR BAG SAMPLE B ... CHUNK SAMPLE I ... WATER TABLE OR SEEPAGE
NOTE: THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE OATE INDICATED IT
IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
PROJECTNO. 07238-42-01
DEPTH
IN
FEET
SOIL
CLASS
(USCS)
TRENCH T13A
ELEV. (MSL.) 301
EQUIPMENT
DATE COMPLETED 04-03-2004
CASE 310
I- w g
2 U.
ir
Q
OT^
02
2 O
O
MATERIAL DESCRIPTION
- 2
- 4
- 10
UNDOCUMENTED FILL
Loose, damp, dark to light brown (mottled), Silty to Clayey, very coarse
GRAVEL; very porous, debris fill consisting of oversize (over 12" diameter)
concrete, asphalt concrete, wood, plastic, trash
GC-GM
TRENCH TERMINATED AT 10 FEET (Caving)
Figure A-15,
Log of Trench T 13A, Page 1 of 1 07238-42-01 .GPJ
SAMPLE SYMBOLS D ... SAMPLING UNSUCCESSFUL B. . STANDARD PENETRATION TEST • . . DRIVE SAMPLE (UNDISTURBED)
^ ... DISTURBED OR BAG SAMPLE B. . CHUNK SAMPLE I. . WATER TABLE OR SEEPAGE
IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES E DATE INDICATED. IT
PROJECT NO. 07238-42-01
DEPTH
IN
FEET
SAMPLE
NO.
>-O O
_l
o
X
SOIL
CLASS
(USCS)
TRENCH T 14
ELEV. (MSL.) 303
EQUIPMENT
DATE COMPLETED 04-03-2004
CASE 310
2 O !-I- 2 y-
H W g
^OT2
w ^ 2 U.
li
DC
a
ii
O 2 2 O O
MATERIAL DESCRIPTION
- 2 -
- 4
- 6 -
'/
UNDOCUMENTED FILL
Loose, damp, medium to light brown (mottled). Gravelly, Clayey SAND; with
some oversize 12" asphalt concrete, and concrete debris, wood
SC
CL-ML
POINT LOMA FORMATION
Hard, moist, light to medium olive, very Silty CLAYSTONE; weathered,
fractured
-Bedding N9E, lONW
-Becomes very hard, massive
TRENCH TERMINATED AT 714 FEET
Figure A-16, 07238-42O1.GPJ
Log of Trench T 14, Page 1 of 1
SAMPLE SYMBOLS ° - UNSUCCESSFUL B ... STANDARD PENETRATION TEST 1 ... DRIVE SAMPLE (UNDISTURBED)
^ ... DISTURBED OR BAG SAMPLE B ... CHUNK SAMPLE I ... 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.
APPENDIX A
SELECTED BORINGS
FROM PREVIOUS INVESTIGATIONS
FOR
CARLSBAD TRACT CT-00-20
CARLSBAD, CALIFORNIA
PROJECT NO. 07238-42-01
I'lWWi-tc oe I^Dl=.r^ ^='-"t<-"'^'li-^l. tlMCilNEERS AND GEOLOGISTS
- • TEST BORING LOG
TYPE 24" 0 Bucket Auger IELEVATION 296.0
Job No. 589-102 - May 8, 19S9 A-l
.viUOKt.a.TABER GHOTECHNiCAU ENGINEERS ANO GEOUOG.STS
T EST BORINIfi I nr;
TYPE 24" 0 Bucket Auger
L32W
"6NI
[49E
3N0r
71W
\8N
\6m
NSK
[ELEVATION 296.0 IBGRING T
13 [2.5 1 ,
Bag 2 I 10
105 21.3 9 2.5 3
15
20
25
30
35
,-Jr4L COLLOVIDM: DarJc yalloi-/ hroxm CLAYEY ^TT
^ I ^nth mixnuta voids and roots
•DEL\lda2.-E0BMATI0N: Poorly bedded, hiaM-'-
fractured oxidized; gray broTm- '
• CLAYEY SILTSTONE • '
...slightly fractured beloir 10'
.13.5'; 6" thick concretion
.at 20'; 4" thick concrfetion
45
NOTES:
End of boring 39".
Nd groundtrater encountered.
No caving.
Backfilled 4/21/89.
Elevation "obtained from plan
dated 3/14/89.
C 3
THIS BORING LOG SUMMARY APPUES ONUY ATTHETIME
ANO LOCATION INDICATED. SUBSURFACE CONDITIONS
MAY DIFFER AT OTHER LOCATIONS ANO TIMES.
i I LOGGED BY DATE
Job No. 689-102 - May 8, 1989 A-5
' ^ '— « I 7-\ C3 C I-v ucul eUMNiCAL ENGINEERS AND GEOLOGISTS
TEST BORING LOG
TYPE 24" 0 Rnr-!rg^ a„.jo>- IELEVATION 284.0
Job No. 689-102 - May 8, 1989 a-2
MOORE S TA B E R GEOTECHNICAL ENGINEERS AND GEOLOGISTS
TEST BORING LOG
Job No. 689-102 - May 8.. 1939 A-3
MOORE S T A B E R GEOTECHNICAL ENGINEERS AND.GEOLOGISTS
TEST BORING LOG
TYPE 24" 0 Bucket Auger |ELEVATION 176.0 TBORING 4
Job NO. 689-102 - Msiy 8, 1939 A-4
TYPE 24" mc^^ Bucket
TEST PIT LOG
270
ALLDVIDM:
<S ANO GEOLOGISTS
[lRN«"
BroTm SILTY CLAY
DEL MAR- F0RI-1ATI0N: Lithofiad, bloc'-y
broT.;n CLkYEY, SILTSTONE i-rLth CLAy
• seacis • . •:
NOTES:
1,
2.
• 3.
4.
5.
Total depth of T.?, 5 •. .
No ground-;atar encountered.
No caving.
Baclcfilled 4-5-89.
Elevation obtained from plan
dated 3-14-89.
[TYPE 24" Wide Bucket
TEST PiT LOG
I ELEV. 220
[CLJ COLLUVro^; Brora SILTT CLAl
DEL MAR.F0Rf<IATI0N: Lithofiad. blocl-y .--ay
CLAYEY SILTSTONE mth oxidation "
staining •
Bloc!cy dark -gray CLAYEY SILTSTONE
NOTES:
r.
2.
3.
4.
5.
•i h
Total depth of T.F. 6.5'.
No groundtratar encountered.
No caving.
BacJcfillad 4-5-89.
Elevation obtained from ^lan
dated 3-4-89.
-1
-1
•<_)
o
-o
—-1
5" UN LOGGED BY KGF
Job No. 589-102 - May 8, 1939
I DATE 4-5-89
A-6
I /A DtrC =°NS"'-TINO ENGINEERS AND GEOLOGISTS
TEST PiT LOG
ELEV
[TYPE 24" Buckat
o
wo
Sl 13
u
-s
kl X
TEST PiT LOG
10-
15-
w
n
20-
[^54^ FILL: I'Jhita fine CLAYEY SA^JD
ICL ALLDVIUr-f: Dar.'c brora SILTY CLAY
I W
a. u.
Ul
a
-I
a
«nT
i<.u
DEL MAR-.F.0RHATI0N:- Dark brovm CLAYEY
SILTSTONE with CLAY saains
NOTES:
1. Total depth of T.P. 9'.
2. No groundv/ater encountered.
3. No caving.
4. Baclcfilled 4-5-39.
5. Elevation obtained from plan
dated 3-4-39.
LOGGED BY KGF
Job No. 589-102 - May 8, 1989
I DATE 4-5-39
A-7
TYPE 24" Buckat
.wuiico ENOIISCERS AND GEOLOGISTS
TEST PIT LOG
ELEV + 155 T.P.N« 5
AILUVIDM: Brora CLAYEY SILT
..scattered concretions.at 5' - I7.._n^„ in d-iainatar ~.
10-
15
20-
.seeoaga
PEL f ILNFORMATION: Lithofied, bloclry bl^ SILTY CLAYSTONE ^-oc../ oro.
NOTES:
- 1. Total depth of T.P. 17 .
2. Seepage at 15'.
3. Caving associated with seeoa-a
4. Baclcfilled 4-5-89. * *
t'ls-'/ation obtained from olan
dated 3-4-89,
TEST PiT LOG
Job No. 689-102 - May 3, 1989
TYPE 24" Wide Bucket
Nll^f
ri4^r Bag 1
=..^«.r.e.e.«3 AND GEOLOGISTS
TEST PIT LOG
TLEv^TTir
ICLI COLLDVIDM: Dark brora SILTY Clay ,.r^
I Sl^msiom concretions
DEL MAR. FORMATIONAL: Lithofied, blo^
. .. rnottled darJc brora SILTY CLAYST^S^
tnth CLAY seams ^i^-u>j^
10
15
20-
i-—f
NOTES:
1.
. 2.
3.
4.
5.
Total depth of T.P. 5.5'.
No groundv/ater encountered.
No caving.
BaCi'cfillad 4/5/89.
Elevation obtained from plan
dated 3-4-89.
TEST PiT LOG
ELEV -f- 238
J°b No. 589-102 -May 8, 1939
i YPE 24" Wide Bun!r.o-f-. TEST PIT \ na
ELEV t 163
^IXO GEOLOGISTS
10
20H
TP.N« • 9
ALLOVIDM: Dark bror-m SILTY CLAY
DEL FOMTION-r LithofiedTTI^
dark brora CLAYEY SILTSTOfk '
NOTES:
1- Total depth :of-test oit.-lO'
i^r^^"-^ ^°-cdpp.o..
4: SSfiJedtSS ^^^^
IlPE2£;j^d6Bucket-
o
.I5I
Wo
~o Si
u
K •» kl
W X
Job No. 689-102 - May 3,
TEST PIT LOG
10
15
20
ELEV 215 I,
^-^ |TRN« 10
I CL[ ALLUVIUM: Dark brora SILTY CLAY
• CLS^I^ ^ ^^^^ERED SILT^-
i~f~.
^OTES:
1. Total depth of test oit 4'.
2. No groundTvater encountered, p. No caving.
H. Backfilled 4/5/89.
1* ^^3/4/89" ^^^^^""^"^ ^^ted
~ I-
X w
ts
1939
l-l *<-i :o
|-<
|3
O
•>n|
LOGGED BY KGF [DATE 4-5-89
A-10
APPENDIX
APPENDIX B
LABORATORY TESTING
Laboratory tests were performed in accordance with generally accepted test methods of the American
Society for Testing and Materials (ASTM) or other suggested procedures. The chunk samples were
tested for their in-place dry density and moisture content. Disturbed bulk samples were tested to
determine compaction and expansion characteristics. The results of the tests are summarized in
tabular and graphical form herewith. The in-place dry density and moisture content of the samples
tested are presented on the logs in Appendix A.
TABLE B-l
SUMMARY OF LABORATORY MAXIMUM DRY DENSITY
AND OPTIMUM MOISTURE CONTENT TEST RESULTS
ASTM D 1557
Sample
No. Description Maximum Dry
Density (pcf)
Optimum Moisture
Content (% dry wt.)
Bl-2 Dark gray, Silty CLAY 113.0 16.0
TA-2 Olive, Silty CLAY 109.7 16.3
TABLE B-ll
SUMMARY OF DIRECT SHEAR TEST RESULTS
Sample
No.
Dry Density
(pcf)
Moisture
Content (%)
Unit Cohesion
(psf)
Angle of Shear Resistance
(degrees)
Bl-1 109.2 17.0 702 27
Bl-7 106.9 17.7 694 34
T6-1* 94.5 19.8 742 43
*Soil sample remolded to 90 percent relative density at near optimum moisture content.
TABLE B-III
SUMMARY OF LABORATORY DENSITY FROM SUBMERGED WAX SAMPLE
Sample
No.
Dry Density
(psf) Moisture Content (%)
T6-1 108.9 17.7
Tll-1 107.0 20.1
*Sample allowed to air-dry from as-received moisture content.
Project No. 07238-42-01 B-l April 22, 2004
APPENDIX M c
APPENDIX C
RECOMMENDED GRADING SPECIFICATIONS
FOR
CARLSBAD TRACT CT-00-20
CARLSBAD, CALIFORNIA
PROJECT NO. 07238-42-01
RECOIVIIVIENDED GRADING SPECIFiCATIONS
1. GENERAL
1.1. These Recommended Grading Specifications shall be used in conjunction with the
Geotechnical Report for the prpject prepared by Geocon Incorporated. The recom-
mendations contained in the text of the Geotechnical Report are a part ofthe earthwork and
grading specifications and shall supersede the provisions contained hereinafter in the case
of conflict.
1.2. Prior to the commencement of grading, a geotechnical consultant (Consultant) shall be
employed for the purpose of observing earthwork procedures and testing the fills for
substantial conformance with the recommendations of the Geotechnical Report and these
specifications. 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
Contractor to assist the Consultant and keep him apprised of work schedules and changes
so that personnel may be scheduled accordingly.
1.3. It shall be the sole responsibility of the Contractor to provide adequate equipment and
methods to accomplish the work in accordance with applicable grading codes or agency
ordinances, these specifications and the approved grading plans. If, in the opinion of the
Consultant, imsatisfactory conditions such as questionable soil materials, poor moisture
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.
2. DEFINITIONS
2.1. Owner shall refer to the owner of the property or the entity on whose behalf the grading
work is being performed and who has contracted with the Contractor to have grading
perfonned.
2.2. Contractor shall refer to the Contractor performing the site grading work.
2.3. Civil Engineer or Engineer of Work shall refer to the Califomia licensed Civil Engineer
or consulting firm responsible for preparation of the grading plans, surveying and verifying
as-graded topography.
GI rev. 07/02
2.4. Consultant shall refer to the soil engineering and engineering geology consulting fum
retained to provide geotechnical services for the project.
2.5. Soil Engineer shall refer to a Califomia licensed Civil Engineer retained by the Owner,
who is experienced in the practice of geotechnical engineering. The Soil Engineer shall be
responsible for having qualified representatives on-site to observe and test the Contractor's
work for conformance with these specifications.
2.6. Engineering Geologist shall refer to a Califomia 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 recormaissance or geologic investigation that was prepared specifically for the
development of the project for which these Recommended Grading Specifications are
intended to apply.
3. MATERIALS
3.1. Materials for compacted fill shall consist of any soil excavated from the cut areas or
imported to the site that, in the opinion of the Consultant, is suitable for use in construction
of fills. In general, fill materials can be classified as soil fills, soil-rock fills or rock fills, as
defined below.
3.1.1. Soil fills are defined as fills containing no rocks or hard lumps greater than 12
inches in maximum dimension and containing at least 40 percent by weight of
material smaller than 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 ofthe rock fill quantity.
GI rev. 07/02
3.2. Material of a perishable, spongy, or otherwise imsuitable nature as determined by the
Consultant shall not be used in fills.
3.3. Materials used for fill, either imported or on-site, shall not contain hazardous materials as
defined by the Califomia 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
not be responsible for the identification or analysis of the potential presence of hazardous
materials. However, if observations, odors or soil discoloration cause Consultant to suspect
the presence of hazardous materials, the Consultant may request from the Owner the
tennination of grading operations wathin the affected area. Prior to resuming grading
operations, the Owner shall provide a written report to the Consultant indicating that the
suspected materials are not hazardous as defined by applicable laws and regulations.
3.4. The outer 15 feet oi soil-rock fill slopes, measured horizontally, should be composed of
properly compacted soil fill materials approved by the Consultant. Rock fill may extend to
the slope face, provided that the slope is not steeper than 2:1 (horizontal:vertical) and a soil
layer no thicker than 12 inches is track-walked onto the face for landscaping purposes. This
procedure may be utilized, provided it is acceptable to the goveming agency, Owner and
Consultant.
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,
where appropriate, shear strength, expansion, and gradation characteristics ofthe soil.
3.6. During grading, soil or groimdwater conditions other than those identified in the
Geotechnical Report may be encountered by the Contractor. The Consultant shall be
notified immediately to evaluate the significance ofthe 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.
GI rev. 07/02
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
ofthis 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 (horizontahvertical), 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
Finish Slope Surface
Remove All
Unsuitable Material
As Recommended By
Soil Engineer Slope To Be Such That
Sloughing Or Sliding
Does Not Occur
See Note 1 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 conqjaction equipment used. The base of the
key should be graded horizontal, or inclined sHghtly into the natural slope.
(2) The outside ofthe 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 ofthe key, the depth and configuration ofthe key may be
modified as approved by the Consultant.
GI rev. 07/02
4.5. After areas to receive fill have been cleared, plowed or scarified, the surface should be
disced or bladed by the Confractor 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 moisture content.
5.2. Compaction of rock fills shall be performed in accordance with Section 6.3.
6. PLACING, SPREADING AND COMPACTION OF FILL MATERIAL
6.1. Soil fill, as defined in Paragraph 3.1.1, shall be placed by the Confractor in accordance with
the following recommendations:
6.1.1. Soil fill shall be placed by the Confractor 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 Confractor 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 Confractor by blading/mixing, or other satisfactory methods until the moisture
content is within the range specified.
GI rev. 07/02
6.1.5. After each layer has been placed, mixed, and spread evenly, it shall be thoroughly
compacted by the Confractor to a relative compaction of at least 90 percent.
Relative compaction is defined as the ratio (expressed in percent) of the in-place
dry density of the compacted fill to the maximum laboratory dry density as
determined in accordance with ASTM D1557-00. Compaction shall be continuous
over the entire area, and compaction equipment shall make sufficient passes so that
the specified minimum relative compaction has been achieved throughout the
entire fill.
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.
6.1.7. Properly compacted soil fill shall extend to the design surface of fill slopes. To
achieve proper compaction, it is recommended that fill slopes be over-built by at
least 3 feet and then cut to the design grade. This procedure is considered
preferable to frack-walking of slopes, as described in the follovwng paragraph.
6.1.8. As an altemative to over-building of slopes, slope faces may be back-rolled with a
heavy-duty loaded sheepsfoot or vibratory roller at maximum 4-foot fill height
intervals. Upon completion, slopes should then be frack-walked with a D-8 dozer
or similar equipment, such that a dozer frack covers all slope surfaces at least
twice.
6.2. Soil-rock fill, as defined in Paragraph 3.1.2, shall be placed by the Confractor in accordance
with the following recommendations:
6.2.1. Rocks larger than 12 inches but less than 4 feet in maximum dimension may be
incorporated into the compacted soil fill, but shall be limited to the area measured
15 feet minimum horizontally from the slope face and 5 feet below finish grade or
3 feet below the deepest utility, whichever is deeper.
6.2.2. Rocks or rock fragments up to 4 feet in maximum dimension may either be
individually placed or placed in windrows. Under certain conditions, rocks or rock
fragments up to 10 feet in maximum dimension may be placed using similar
methods. The acceptability of placing rock materials greater than 4 feet in
maximum dimension shall be evaluated during grading as specific cases arise and
shall be approved by the Consultant prior to placement.
GI rev. 07/02
6.2.3. For individual placement, sufficient space shall be provided between rocks to allow
for passage of compaction equipment.
6.2.4. For windrow placement, the rocks should be placed in frenches excavated in
properly compacted soil fill. Trenches should be approximately 5 feet wide and 4
feet deep in maximum dimension. The voids around and beneath rocks should be
filled with approved granular soil having a Sand Equivalent of 30 or greater and
should be compacted by flooding. Windrows may also be placed utilizing an
"open-face" method in lieu of the french procedure, however, this method should
first be approved by the Consultant.
6.2.5. Windrows should generally be parallel to each other and may be placed either
parallel to or perpendicular to the face of the slope depending on the site geometry.
The minimum horizontal spacing for windrows shall be 12 feet center-to-center
with a 5-foot stagger or offset from lower courses to next overlying course. The
minimum vertical spacing between windrow courses shall be 2 feet from the top of
a lower windrow to the bottom of the next higher windrow.
6.2.6. All rock placement, fill placement and flooding of approved granular soil in the
windrows must be continuously observed by the Consultant or his representative.
6.3. Rock fills, as defined in Section 3.1.3., shall be placed by the Confractor in accordance with
the following recommendations:
6.3.1. The base of the rock fill shall be placed on a sloping surface (minimum slope of 2
percent, maximum slope of 5 percent). The surface shall slope toward suitable
subdrainage outlet facilities. The rock fills shall be provided with subdrains during
construction so that a hydrostatic pressure buildup does not develop. The subdrains
shall be permanently connected to confrolled drainage facilities to confrol post-
construction infilfration of water.
6.3.2. Rock fills shall be placed in lifts not exceeding 3 feet. Placement shall be by rock
trucks fraversing previously placed lifts and dumping at the edge of the currently
placed lift. Spreading of the rock fill shall be by dozer to facilitate seating of the
rock. The rock fill shall be watered heavily during placement. Watering shall
consist of water trucks fraversing in front of the current rock lift face and spraying
water continuously during rock placement. Compaction equipment with
compactive energy comparable to or greater than that of a 20-ton steel vibratory
roller or other compaction equipment providing suitable energy to achieve the
required compaction or deflection as recommended in Paragraph 6.3.3 shall be
GI rev. 07/02
utilized. The number of passes to be made will be detennined as described in
Paragraph 6.3.3. Once a rock fill lift has been covered with soil fill, no additional
rock fill lifts will be permitted over the soil fill.
6.3.3. Plate bearing tests, in accordance with ASTM 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 pits shall be excavated by the Confractor 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 wall 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 roc^ fill placement.
GI rev. 07/02
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, 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
compacted.
7.2. The Consultant shall perform random field density tests ofthe compacted soil or soil-rock
fill to provide 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.
GI rev. 07/02
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).
7.6.1.3. 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 Fills
7.6.2.1. Field Plate Bearing Test, ASTM Dl 196-93 (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
8.1. During construction, the Confractor shall properly grade all excavated surfaces to provide
positive drainage and prevent ponding of water. Drainage of surface water shall be
confrolled to avoid damage to adjoining properties or to finished work on the site. The
Confractor shall take remedial measures to prevent erosion of freshly graded areas until
such time as permanent drainage and erosion confrol features have been installed. Areas
subjected to erosion or sedimentation shall be properly prepared in accordance wdth the
Specifications prior to placing additional fill or structures.
8.2. After completion of grading as observed and tested by the Consultant, no further
excavation or filling shall be conducted except in conjunction with the services of the
Consultant.
GI rev. 07/02
LIST OF REFERENCES
Geotechnical Investigation Update, Fox-Miller Property, prepared by AGRA, dated July 6, 2000.
Second Response to City ofCarlsbad Review Comments, prepared by AMEC, dated April 18, 2001.
Peer Review of Geotechnical Recommendations for 1.5 to l(horizontal to vertical) Slope, Fox-Miller
Property, prepared by Leighton and Associates, dated November 30, 2001.
Geotechnical Response to City of Carlsbad/Peer Review Comments, Fox-Miller Property, prepared
by AMEC, dated December 14, 2001.
Peer Review of Geotechnical Response for the 4-Foot-High Vertical Cut at the Base ofthe 1.5 to 1.0
(Horizontal to Vertical) Slope, Fox-Miller Property, prepared by Leighton and Associates
dated December 30, 2003.
Anderson, J. G., Synthesis of Seismicity and Geologic Data in Califomia, U.S. Geologic Survey
Open-File Report 84-424, 1984, pp. 1-186.
Bfrkeland, P. W., Soils and Geomorphology, Oxford University Press, 1984.
Blake, T. F., EQFAULT, A Computer Program for the Deterministic Prediction of Peak Horizontal
Acceleration fi-om Digitized Califomia Faults, User's Manual. 1989a, p. 79.
, EQSEARCH, A Computer Program for the Estimation of Peak Horizontal Acceleration from
Southem Califomia Historical Earthiquake Catalogs, User's Manual. 1989b, p. 94.
Jennings, C. W., Fault Map ofCalifomia with locations of Volcanoes, Thermal Springs and Thermal
Wells, Califomia Division of Mines and Geology, 1975 (revised 1987).
Tan, Siang S. and M. P. Kennedy, Geologic Map ofthe Oceanside. San Luis Rey, and San Marcos 7.5'
Quadrangles, San Diego County, Califomia, Califomia Division of Mines and Geology, Open-
File Report 96-02, Plate 1, 1996.
Unpublished reports, aerial photographs, and maps on file with Geocon Incorporated.
Weber, F. H., Jr., Geology and Mineral Resources of San Diego County, Califomia, Califoraia Division
of Mines and Geology, No. 3, 1963.
Wesnousky, S. G., Earthquakes, Quatemary Faults, and Seismic Hazard in Califomia, Joumal of
Geophvsical Research. Vol. 91, No. B12, 1986, pp. 12, 587, 631.
Project No. 07238-42-01 ^p^i 22, 2004