HomeMy WebLinkAboutSP 210; POINSETTIA LANE STORM DRAIN; GEOTECHNICAL INVESTIGATION FOR STORM DRAIN SYSTEM ASSESSMENT DISTRICT; 1994-06-01I
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GEOTECHNICAL INVESTIGATION
FOR
STORM DRAIN SYSTEM
ASSESSMENT DISTRICT
CARLSBAD, CALIFORNIA
sf 210
PREPARED FOR
KAIZA POINSETTIA CORPORATION
CARLSBAD, CALIFORNIA
PREPARED BY
GEOCON INCORPORATED
SAN DIEGO, CALIFORNIA
JUNE 1994
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Project No. 05333-12-01
June 23, 1994
Kaiza Poinsettia Corporation
A California Corporation
7220 Avenida Encinas, Suite 200
Carlsbad, California 92009
Attention:
Subject:
Gentlemen:
Mr. Brian Murphy
STORM DRAIN SYSTEM
ASSESSMENT DISTRICT
CARLSBAD, CALIFORNIA
GEOTECHNICAL INVESTIGATION
In accordance with your authorization and our proposal dated April 11, 1994, we have performed
a geotechnical investigation for the subject project. The accompanying report presents the fmdings
from our study and our conclusions and recommendations pertaining to the geotechnical engineering
aspects of the storm drain system installation.
If you have any questions regarding this report, or if we may be of further service, please contact
the undersigned at your convenience.
Very truly yours,
AS:DFL:slc
(4/del)
(4/del)
Addressee
O'Day Consultants
Attention: Mr. George O'Day
i~
CEG 1778
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TABLE OF CONTENTS
PURPOSE AND SCOPE ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 1
SITE AND PROJECT DESCRIPTION ................................. 2
SOIL AND GEOLOGIC CONDITIONS ................................ 3
Undocumented Fill (Qudt) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 4
Topsoil (Unmapped) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 4
Terrace Deposits (Qt) , ................................. '. . . . . .. 4
Santiago Formation (Ts) ...................................... 5
GROUNDWATER ............................................. :. 5
GEOLOGIC HAZARDS .......................................... 5
Faulting and Seismicity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . , . .. 5
Liquefaction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 7
CONCLUSIONS AND RECOMMENDATIONS ........................... 8
General. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 8
Dewatering ....................................,.......... 9
Temporary Shoring and Lateral Loads ..............•............. 10
Grading and Backfilling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 11
Bulking and Shrinkage Factors ................................. 12
Slope Stability . . . . . . . . . . . . . . . .......................... : . . 13
Reactive Soil Characteristics ................................ " . . 15
Alignment and Improvement Plan Review .......................... 15
LIMITATIONS AND UNIFORMITY OF CONDITIONS
MAPS AND ILLUSTRATIONS
Figure 1, Vicinity Map
Figure 2, Site Plan
Figure 3, Slope Stability Analysis -Cut and Fill Slopes
APPENDIX A
FIELD INVESTIGATION
Figures A-1 -A-10, Logs of Borings
Figure A-3, Off-Site Boring No. B-3 (from Project No. 05318-12-01)
APPENDIXB
LABORATORY TESTING
Table B-1, Summary of Direct Shear Test Results
Table B-II, Summary of Laboratory Maximum Dry Density and Optimum Moisture
Content Test Results
Figure B-1 -B-2, Gradation Curves
Figures B-3 -B-4, Consolidation Curves
APPENDIX C
RECOMMENDED GRADING SPECIFICATIONS
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Project No. 05333-12-01
June 23, 1994
GEOTECHNICAL INVESTIGATION
PURPOSE AND SCOPE
This report presents the results of a geotechnical investigation for the storm drainsystelJl of the
proposed Assessment District development in Carlsbad, California (see Vicinity Map, FigUre 1).
The purpose of the investigation was to evaluate the surface and subsurface soil· and geologic
conditions at the site and, based on the conditions encountered, to provide recommendations relative
to the geotechnical engineering aspects of project development.
The scope of the investigation included a review of the following:
1. Geotechnical Investigationsfor Avenida Encinas AssessmentDistrict; Carlsbad,
California, prepared by Geocon Incorporated, dated June 14, 19~4.
2.
3.
4.
5.
6.
Geotechnical Investigation for Poinsettia Shores, Carlsbad, California,
prepared by Geocon Incorporated, dated June 3, 1994.
Improvement Plans for Storm Drain, Assessment District and Plans for Grading
and Improvement of Desilting Basin, Assesstnent District, prepared' by O'Day
Consultants, stamp dated March 30, 1994.
Update Soil Investigation Report for Public Access Trial, Kaiza Poinsettia
(formally Batiquitos Lagoon Educational Park, Phase I), Carlsbad, California,
prepared by Woodward-Clyde Consultants, dated October 24, 1991.
Geotechnical Investigation for Proposed Batiquitos Lagoon, Educational
Park -Phase II and A Portion of Phase I, Carlsbad, California, prepared by
Woodward-Clyde Consultants, dated June 4, 1986.
Alignment Study Avenida Encinas and Storm Drain Assessment iJistrict,
prepared by O'Day Consultants, undated.
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Project No. 05333-12-01
June 23, 1994
The scope of the field investigation consisted of a site reconnaissance by an engineering geologist
and the excavation of 10 exploratory borings. Data from one additional boring, extracted from the·
referenced geotechnical investigation dated June 3, 1994, (Reference 2) was also utilized in this
study. Laboratory tests were performed on selected soil samples obtained at various depths in the
excavation to evaluate pertinent physical properties. A detailed discussion of the field investigation
and laboratory test results are presented in Appendices A and B. The recorrimendations presented
herein are based on an analysis of the data obtained and experience with similar soil and geologic
conditions.
SITE AND PROJECT DESCRIPTION
The project consists of construction of approximately 5,300 lineal feet of storm drain, traversing
north-south between Poinsettia Lane and the Batiquitos Lagoon in the city of Carlsbad, California.
The storm drain varies in size from 24-inch-to 78-inch-diameter reinforced concrete pipe. The
majority of the alignment will be located within the western margin of the Atcltinson Topeka and
Santa Fe (AT&SF) railroad right-of-way. The southern portion of the alignment will be located
along the eastern margin of Carlsbad Boulevard. The storm drain will cross beneath the existi11g
AT&SF railway at two locations. One crossing is planned at the head of the alignment, and the
second is a lateral tying in from the adjacent Poinsettia Shores project at approximately:midway
along the alignm~nt. Jack and bore pits and tunnel excavations are planned for the railway
crossings. It is our understanding that the storm drain pipe will have an average depth of 20 feet
below existing grade. Grading associated with the project includes the construction of a desilting
basin adjacent to the Carlsbad Boulevard, just north of the Batiquitos Lagoon.
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Project No. 05333-12-01
June 23, 1994
It is our understanding that the storm drain alignment may be altered. This change would entail
maintaining the pipe location near the railroad and not shifting to the west until within the proximity
of the Avenida Encinas bridge crossing. For this reason, exploratory borings BS-9 and BS-10were
excavated.
The project site elevation ranges from approximately 52 feet Mean Sea Level (MSL) near Poinsettia
Lane at the northern end of the project to approximately 13 feet MSL at the proposed desilting basin
to the south. The area of the alignment is undeveloped except for a number other utility lines
including water, gas and telephone lines that cross the proposed alignment at various locations.
A review of the grading plans for the desilting basin indicates that the grading will include a
construction of an approximately lO-foot-high dike and cut slopes of up to 28 feet in height. Th~
base map used in this study consists of a 100-scale alignment stUdy, Reference No. 6 (see
Figure 2).
The above discussion is based on a site reconnaissance and a review of the referenced alignment
study. It is understood that, as future development plans progress, Geocon Incorporated will be
offered the opportunity for the review of these documents.
SOIL AND GEOLOGIC CONDITIONS
The site was found to be underlain by undocumented fill, topsoils and formational soils of the
Terrace Deposits and the Santiago Formation. Each of these formational and surficial units is
described below.
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Project No. 05333-12-01
June 23, 1994
Undocumented Fill (Qudf)
Undocumented fill soils are associated with the existing utility trench backfills within the area·
of study. No undocumented fill was encountered within the borings; however, based on our
experience, it is not uncommon for old fill areas to be present in areas utilized for agriculture where
their presence is masked by cultivation activities. Where large aIIlounts of fill soils are ,encountered
within the excavations, special consideration such as flattening side slopes for excl:!.vations or more
extensive shoring may be required.
Topsoil (Unmapped)
Topsoils consisting of loose, dry to moist, silty sand and 1 to 2 feet in thickness were encountered
covering the majority of the site. At least the upper 12 inches of the topsoils had been reworked
by cultivation. Due to shallow depths of these materials, it is unlikely to impact the project
development.
Terrace Deposits (00
Quaternary Marine Terrace Deposits comprise the entire project site undedying the surficial soils.
These materials consist of medium dense, damp to moist, light brown silty sand to fine to medium
cohesionless sand. The silty sand portion of the Terrace Deposits should provide adequate shear
strength for stabil~ty of temporary excavations. However, the cohesionless sand lenses and layers
will be highly unstable and will require proper stabilization methods during excavations and pipe
installation.
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Project No. 05333-12-01
June 23, 1994
Santiago Formation (Ts)
The Eocene-age Santiago Formation underlies the entire site beneath the Terrace Deposits. The
Santiago Formation consists of dense to very dense, moist, gray to very light green, silty to clayey
sandstones interbedded with siltstones and claystones. These materials were encountered in the
majority of the borings at the depths ranging from 2 feet (Boring No. BS-8) to 30 feet (Boring
No. BS-2). The Santiago Formation possesses good bearing characteristic and should provide
suitable support for the pipe and bedding loads.
GROUNDWATER
Perched groundwater was encountered in the majority of the borings at the depths ranging from 12
feet in Boring No. BS-5 to 29 feet in Boring No. BS-l. Perched groundwater levels should be
anticipated to vary seasonally, principally, as a function of the amount of rainfall. Hased on the
conditions encountered at the time of the field investigation, groundwater is anticipated to
significantly impact the excavations for the storm drain installation and will require modifying
conventional installation! construction procedures.
GEOLOGIC HAZARDS
Faulting and Seismicity
Based on this fiel~ investigation, and review of aerial 'photographs and published geologic maps, the
site is not located on any active or potentially active fault trace as defined by the Caijfornia Division
of Mines and Geology.
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Project No. 05333-12-01
June 23, 1994
Undocumented Fill (Oudf)
Undocumented fill soils are associated with the existing utility trench backfills within the area
of study. No undocumented fill was encountered within the borings; however ,based on our
experience, it is not uncommon for old fill areas to be present in areas utilized for agriculture where
their presence is masked by cultivation activities. Where large amounts offill soils are encountered
within the excavations, special consideration such as flattening side slopes for excavations or more
extensive shoring may be required.
Topsoil (Unmapped)
Topsoils consisting of loose, dry to moist, silty sand and 1 to' 2 feet in thickness were encountered
covering the majority of the site. At least the upper 12 inches of the topsoils had been reworked
by cultivation. Due to shallow depths of these materials, it is unlikely to frnpact the project
development.
Terrace Deposits (On
Quaternary Marine Terrace Deposits comprise the entire project site underlying the surficial soils.
These materials consist of medium dense, damp to moist, light brown silty sand to fine to medium
cohesionless sand. The silty sand portion of the Terrace Deposits should provide adequate shear
strength for stabil~ty of temporary excavations. However, the cohesionless sand lenses and layers
will be highly unstable and will require proper stabilization methods during excavations and pipe
installation.
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Project No. 05333-12-01
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The Rose Canyon and Coronado Banks Fault Zones, the closest active faults, lie approximately 5
and i8 miles to the west, respectively. As shown on Table I, a "maximum probable." earthquake
of Magnitude 6.5 occurring on the Rose Canyon Fault could result in a peak site acceleration of
approximately 0.27 g. Other active faults listed on Table I are more distant from the site and,
hence, ground shaking from earthquakes on those faults will be less intensive. It is our opinion that
the site could be subjected to moderate to severe ground shaking in the event of a major earthqUake
along any of the above-mentioned faults; however, the seismic risk at the site is not considered
significantly greater than the surrounding area.
TABLE 1*
DETERMINISTIC SITE-PARAMETERS FOR SELECTED FAULT
Casa Lorna-Clark (San Jacinto) 50 7.50 0.04 7.00 0.03
Coronado Banks Fault Zone J8 6.75 0.11 ~.oo 0.07
Coyote Creek (San Jacinto) 52 7.50 0.04 7.00 0.03
Elsinore 26 7.50 0.10 6.75 0.07
GIn. Helen-Lytle Cr-Clremnt 53 7.50 0.04 7.00 0.03
Newport -Inglewood 43 7.50 0.06 6.50 0.03
Rose Canyon 5 7.00 0.36 6.50 0.27
San Diego Trough 29 6.50 0.06 6.00 0.04
*Derived from Blake T. F. EQFAULT, Computer Programfor Deterministic Prediction of
Peak Horizontal Acceleration from Digitized California Faults, 1989, a, updated 1991.
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Project No. 05333-12-01
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Liquefaction
In consideration of the dense formational soils underlying the site and lack of a permanent water
table near the ground surface, it is our opinion that liquefaction does not present a significant
geologic hazard to the proposed site development.
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Project No. 05333-12-01
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CONCLUSIONS AND RECOMMENDATIONS
General
1. The results of the investigation indicate that no geotechnical constraints are known to be
present within the alignment which would preclude the construction of the proposed storm
drain pipeline, provided the recommendations of this report are followed. It should be noted
that borings were conducted at approximately 300-to 1,000-foot intervals along the
alignment and, hence, subsurface conditions may vary between locations.
2. It is anticipated that the majority of the alignment may be excavated with typical heavy duty
excavating equipment.
3. Perched groundwater and/or seepage was encountered in all borings except Boring No. BS-8,
located in the desilting area. It is anticipated that dewatering will be required during
installation of the pipeline and that groundwater-related constraints will significantly impact
the project as presently proposed.
4. Various zones of cohesionless sands were encountered within the Terrace Deposits. These
zones will create significant instability within the excavations walls. Extensive shoring/
shielding will be required during the installation of the storm drain. The cohesionless sand
zones will also be a major concern for selecting the type of equipment and procedures for
jack and bore operations underneath the railroad tracks.
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Project No. 05333-12-01
June 23, 1994
5. In areas where the pipelines are within 2 feet of groundwater levels, the formational soils
should be overexcavated at least 1 foot and backfilled to pipe grade with a well-graded
gravel. To guard against the piping of adjacent trench sidewall soils and trench backfill
materials, the gravel bed should be wrapped in a suitable filter fabric (Mirafi 140N or
equivalent). The gravel bed will also provide a stable working platform and subgrade for
pipeline installation.
6. It is anticipated that excavated on-site soils will generally be suitable for use as compacted
fill. Very wet to moist soils may require drying or mixing with drier soils prior to lise as
trench backfill.
Dewatering
7. Perched groundwater conditions will necessitate local dewatering, depending on [mal design
elevations of the pipeline. It is recommended that the groundwater level be maintained at
least 1 to 2 feet below the excavation bottom to provide stable working conditions. Possible
dewatering systems include sump pumps. It is recommended that a contractor familiar in the
design and construction of dewatering systems be retained to conduct dewatering in
conjunction with the pipe installation and or jack and bore operations.
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Project No. 05333-12-01
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Temporary Shoring and Lateral Loads
8. Excavation shoring should be designed for a pressure equal to 35H psf, where "H" equals
the depth of the excavation in feet. This value assumes no groundwater or surcharge loading
within a distance to the top of the trench equal to the depth of the trench. Shoring extending
below local groundwater levels should also be designed to resist the appropriate hydrostatic
forces.
9. Shoring which is subject to vehicle or construction traffic surcharge within a horizontal
distance equal to or less than the height of the wall should be designecl for an. addi~ional
uniform horizontal pressure of 250 psf. This design value should be considered preliminary
and reassessed based on actual loads from equipment planned to work adjacent to the trench.
In addition, where excavated soils will be stockpiled within a distance closer to the trench
than the depth of trench, this surcharge loading ShOl,1ld be accounted for in the shoring
design.
10. All shoring should be designed by a qualified professional consultant familiar with the design
of tempor~ earth retaining systems as well as-compliance with governing agency codes.
11. Lateral loads may be resisted by an allowable passive pressure equiva.lent to that generated
by a fluid weighing 300 pounds per cubic foot (pet). A coefficient of friction of 0.35 may ,
be used to calculate the resistance to sliding along the concrete/soil and pipeline/soil inter-
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Project No. 05333-12-01
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face. The passive pressure may be combined with friction for resisting la.teralloads. These
passive pressure values may be utilized in design of reaction pits for the jack and bore pipe
installation operations.
Grading and Backfilling
12. Grading for the desilting basin and the trench backfill should be performed in accordance
with the Recommended Grading Specifications contained in Appe:p.dix C and the city of
Carlsbad Grading Ordinance. Where the recommendations of Appendix C conflict with this
section, the recommendations of this section take precedence.
13. Site preparation should begin with the removal of deleterious matter and vegetation, asphalt
concrete, and concrete. The depth of removal should be such that material to be used as fill
soil is free of organic or unsuitable material. Unsuitable material generated from on-site
operations should be removed from the project site.
14. Pipe bedding and shading materials should conform to civil design and/or agencyspeci-
fications. ~t is recommended that shading material placed under the haunches and to a level
of just over the top of pipe consist of granular soils with a Sand Equivalent greater than 30.
15. Trench backfill should consist of predominantly granular material no greater than 6 inches
in maximum dimension and be compacted in lifts with thicknesse~ no greater than that which
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Project No. 05333-12-01
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will allow proper compaction. The backfill should be compacted to a minimum relative
compaction of 90 percent, at or up to 3 percent over optimum moisture content as determined
by ASTM D1557-91.
16. Grading for the proposed desilting basin will involve construction of an approximately 10-
foot-high dike, a maintenance access road and a cut slope approximately 28 feet high, east
of the desilting basin. Areas to receive fill soil should be scarified to a minimum depth
of 12 inches, moisture conditioned, and be compacted to a minimum relative compaction
of 90 percent, at or up to 3 percent over optimum moisture content as determined by
ASTM D 1557-91. The fill soils free of organic matters should then be placed and compacted
to 90 percent relative compaction to achieve design finish grade elevations. Cohesionless
sands should be restricted from the face of fIll slopes as discussed below.
Bulking and Shrinkage Factors
17. Estimates of embankment bulking and shrinkage factors are based on comparing laboratory
compaction tests with the density of the material .in its natural state as encoUntered in the
exploratory excavations. It should be emphasized that variations in natural soil density, as
well as in compacted fill density, render shrinkage value estimates very approximate. As an
example, the contractor can compact the fill soils to any relative compaction of 90 percent
or higher of the maximum laboratory density. Thus, the contractor has approximately a 10
percent range of control over the fill volume. Based on the limited Work performed to date,
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Project No. 05333-12-01
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it is our opinion that the following shrinkage and bulking factors can be used as a basis for
estimating how much the on-site soils may shrink or swell (bulk) when excavated from their
natural state and placed as compacted fills.
TABLE II
SHRINK/BULK FACTORS
Undocumented fill and topsoil
Terrace Deposits
Slope Stability
5 to 10 percent shrhlic
2 to 5 percent bulk
18. The stability of proposed permanent cut and fill slopes with respect to dt;:ep-seated failure was
analyzed using Janbu's method for dimensionless slopes. The results of the analysis indicate
that 2: 1 (horizontal to vertical) cut and fill slopes possess a calculated factor of safety in
excess of 1.5 for the height of approximately 30 feet. The slope stability analysis is
presented in Figure 3.
19. All permanent cut slopes should be observed and logged by an engineering geologist during
the grading operations to verify that the soil and geologic conditions exposed do not differ
significantly from those anticipated.
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Project No. 05333-12-01
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20. Cohesionless sands should not be placed within the outer 15 feet of the fill slopes. If such
materials are exposed within the cut slopes, mitigation measures, such as construction of a
stability fill, may be considered.
21. All slopes should be planted, drained and properly maintained to help reduce erosion. Slope
planting should consist of a drought-tolerant plants having a variable root depth. Slope
watering should be kept to a minimum to just support the plant growth.
22. Temporary cut slopes excavated as a part of the trenching operation may, in general, be
considered stable with an inclination of 1:1 (horizontal:vertical). This assumes cdhesionless
sands are not present within the excavated slope or within that trench zone berteaththe slope.
For this condition, slopes should be flattened to at least 2: 1 (horizontal:vertical) or shallower.
Temporary cut slope stability will vary and should be evaluated on a fielq/site-specific-
condition basis. It is considered the responsibility of the installation contractor to staff the
field operations with a qualified person knowledgeable of trenching operations and applicable
local, state; and federal regulations and codes dealing with trench safety.
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Project No. 05333-12-01
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Reactive Soil Characteristics
23. Testing for reactive soil properties, such as pH and resistivity, were not within the scope of
this study. Geocon Incorporated does not practice in the field of corrosion engineering.
Therefore, if this information is required in design for this project, a qualified design
consultant specializing in corrosion engineering should be retained.
Alignment and Improvement Plan Review
24. Geocon Incorporated should review the project design plans as they become available to
provide additional analyses and recommendations where required.
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LIMITATIONS AND UNIFORMITY OF CONPITIONS
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
construction, or if the proposed construction 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 corrosive materials was .
not part of the scope of services provided by Geocon Incorporated.
2. This report is issued with the understanding that it is the responsibility of the owner, or of
his representative, to ensure that the information and recommendations contained herein are
brought to the attention of the architect and engineer for the project and incorporated into
the plans, and the necessary steps are taken to see that the contractor and subcontractors
carry out such,recommendations in the field.
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 be 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 th,e
broadening of knowledge. Accordingly, the findings Qf 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.
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SOURCE: U.S.G.S. QUADRANGLE
ENCINITAS, CALIFORNIA
PHOTOREVISED 1975
GEOCON
INCORPORATED
GEOTECHNICAL ENGINEERS AND ENGINEERING GEOLOGISTS
6960 FLANDERS DRIVE -SANDTEGO, CALIFORNIA 92121-297-1
PHONE 619 558-6900 • FAX 619 558-6159
AS /RSS I
SCALE: 1" = 2QQO' N
VICINITY MAP
STORM 'DRAIN SYSTEM
ASSESSMENT DISTRICT
CARLSBAD, CALIFORNiA
DATE 6·23·1994 'I PROJ. NO. 05333· 12·01 I FIG. 1
RS5.GSlTllPL.WJ3
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PROJECT No 05333-12-01"
ASSUMED CONDITIONS:
Slope Height
Slope Inclination
Total Unit Weight of Soil
Angle of Internal Friction
Apparent Cohesion
No Seepage Forces
H = 30 feet
2:1 (Horizontal:Vertical)
'Y = 125 pounds per cubic foot
¢ = 30 degrees
C = 400 pounds per square foot
ANALYSIS:
Ac</> = ):H tan 11. Equation (3-3), Reference 1
C
FS = Nc£ Equation (3-2), Reference 1
'YH
ACt/> = 5.4 Calculated Using Eq. (3-3)
Ncr = 22 Detennined Using Figure 10, Reference 2
FS = 2.3 Factor of Safety Calculated Using Eq. (3-2)
.
REFERENCES
(1) Janbu, N., Stability Analysis of Slopes with Dimensionless Parametf;rs, Harvard Soil Mechanics,.
Series No. 46, 1954.
(2) Janbu, N., Discussion of J.M. Bell, Dimensionless Pa~ameters for Homogeneous Earth Slopes,
Journal of Soil Mechanics and Foundation Design, No. SM6, November 1967.
SLOPE STABILITY ANALYSIS -CUT'AND FILL SLOPES
STORM DRAIN SYSTEM
ASSESSMENT DISTRICT
CARLSBAD, CALIFORNIA
FIGURE 3.
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Project No. 05333-12-01
June 23, 1994
APPENDIX A
FIELD INVESTIGATION
The field investigation was performed on May 9 through May 11, 1994, and consisted of the
excavation of 10 small-diameter borings. One additional boring (B-3) has been extracted from the
geotechnical investigation of the adjacent subdivision (report dated June 3, 1994). Theapproximate
locations of the exploratory borings are shown on Figure 2.
The small-diameter borings were advanced to depths of 17 to 32 feet below existiI;lg grade using
a Mobile Drill B-61 truck-mounted drill rig equipped with an eight-inch-diameter hollow stem
auger. Relatively "undisturbed" samples were obtained by driving a 3-inch, split-tube sampler into
the "undisturbed" soil mass with blows from a 140-pound hammer falling 30 .inches. The sampler
was equipped with a I-inch by 23fa-inch-diameter, brass sampler rings to facilitate removal and
laboratory testing. Disturbed bulk samples were also obtained at selected depths.
The soils encountered in the borings and trenches were visually examined, classified; and logged.
Logs of the borings are presented on Figures A-I through A-lO. The log ofthe off-site boring B-3
is presented on Figure A-3, but noted as Project No. 05318-12-01. The logs depict the soil and
geologic conditions encountered and the depth at which samples were obtained.
IpROJECT NO 05333-12-01
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DEPTH
IN
FEET
I-0
I--
I-2 -
I--
I-4 -
I--
I-6 -
I--
I-8 -
I--
I-10 -
I--
12 -
-
14 -
I--
I-16 -
I--
I-18 -
I--
20 -
-
22 -
I--
24 -
-
I-26 -
-
28 -
-
30 -
-
32
0:: >-w t!) l-0 <I: ...I ::I SOIL SAMPLE 0 C'l CLASS NO. ::I: z I-::J (USCS) H 0 ...I 0:: t!)
J;:I" C;:M
"'1. 1'"1"
r-ll -I BSI-l
:'1 r!" :1.l J 11"1 BSI-2 SM
:'1 r!" :1.l
11"1
:'j r!"
BSI-3 ltn
. "
" "
" " "
" " "
BSI-4 1 " " SP
" "
" " " " " " " . "
" "
" "
BSI-5[ :1.1:1" li "I
:'1 t·," :1-:1"
li "'
BSI-6 1 :'1 r ," SM
:1-l
li "' :'1 r ," J -:1-~. :1"
BSI-7[ ::f:~::~· SM :rjo:f: .. :1~·
BORING BS 1 z w",--
Ou • HZI--I-<I:u.
ELEV. (MSL.) 56 DATE COMPLETED 5/9/94 _ ~I-~ I-CI)::I WHO
EQUIPMENT B-61 MOBILE DRILL zCl)...I WWIO 0..0::",
MA TERIAL DESCRIPTION
TOPSOIL
Loose,dry, medium brown, Silty, fine to medium I SAND with little rootlets I-15
TERRACE DEPOSITS l-
Medium dense, damp, dark reddish brown, Silty fine I-
to medium SAND
-Becomes moist at 4 feet I-21 l-
-Becomes wet to very wet, orang ish brown at 7-feet '-
'-
l-
-Becomes dense I-31
I-
--------------------------------------
Becomes light orang ish brown, fine to medium I-
SAND, cohesionless I-
f-40
'-
'--Becomes dark orangish brown
'-
~
--------------------------------------33 Becomes light orangish brown, Silty fine to medium I-
SAND ,l-
I-
I-
'l-45 '-
'-
f-
-Water table at 27 feet I-
SANTIAGO FORMA nON -, 56
Dense to very dense, very wet to saturated, light ....
grayish brown, Silty fine SANDSTONE /
BORING TERMINATED AT 32 fEET
Figure A-1 Log of Boring BS 1. page 1 of 1
>-,...
1-,... WX H • 0::'" Cl)u. ::JI-ffi· I-z aU Cl)w
-. HI-)000.. Oz 0:::'"' 1:0
C'l -u
114.2 6.6
101.8 7.0
100.4 7.7
KSDS
I SAMPLE SYMBOLS D ... SAMPLING UNSUCCESSFUL
~ ••• DISTURBED OR BAG SAMPLE
IJ ... STANDARD PENETRATION TEST ••• ,. DRIVE SAMPLE (UNDISTURBED)
~ ••• CHUNK SAMPLE ~ ••• WATER TABLE OR, SEEPAGE
I NOTE: THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT TH~
DATE INDICATED. IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCAT,IONS AND TIMES.
I
_ROJECT NO 05333-12-01
I DEPTH
IN
I FEET
I I-0
-
2 -
I I--
4 -
-I 6 -
I--
I I-8 -
I--
I-10 -
I I--
I-12 -
I: -
14 -
I--
I: 16'-
-
I
I
I
I
I
I
I-18 -
I--
I-20 -
I--
I-22 -
t--
I-24 -
I--
I-26 -
I--
I-28 -
I--
I-30 -
r--
f-32
0:: >-UJ t!) I-0 <I: -' 3 SOIL SAMPLE 0 C) CLASS NO. :J: z I-;:) (USCS) H 0 -' 0:: t!)
-1 ' _: --"l-,d-I SM
BS2-1 1:1-'l 11-1
:'1 r [-
BS2-2 I :1· -"I-SM l,1-1
:'1 rt-
:1.-"1-11-1 1:1 t.,_ BS2-3 -·r· :1.-"1-"1"-1-1
:'1 t'l-:1· l
'I. i -
BS2-4 1 :1-"l li -, SM
:'1 r I-
:1--"!-
:1"-1-,
BS2-S I ., ------SP -----------
BS2-6 1 :1,1-"1-
l1 -,
:'1 t'l-! SM
:l-"l-J-t -,
BS2-7 ~ ~x.f.! ~~ SC .,:~
BORING BS 2 Z ';-" 'oUJ • H~I-i:=·~ ELEV. (MSL.) 54 DA TE COMPLETED 5/9/94 1-(1)3 UJHO Z(l)...! EQUIPMENT B-61 MOBILE DRILL UJUJ ea .
'0. 0::"".
MATERIAL DESCRIPTION
TOPSOIL I-
Loose to medium dense, dry, medium brown, Silty
1\ fine to medium SAND with few rootlets / I-28
TERRACE DEPOSIT
Medium dense, moist, dark reddish brown, Silty fine l-
to medium SAND l--Becomes moist to wet, orangish brown 20 l-
l-
I-
l-
l-
-Becomes dense 57
l-
l-
'I-
.f'-
--------------------------------------32 Becomes light orangish brown, slightly Silty fine l-
SAND, cohesionless I-
I-
-Becomes Silty, fine to medium SAND l-
--------------------------------------61 Becomes light orangish brown, fine SAND l-
cohesionless I-
I-
I-
-----------------------------~--------
Becomes very wet to saturated, very light orangish 52 l-
brown, Silty fine SAND l--Water table at 27 feet I-
l-
SANTIAGO FORMATION . 50/5" l-
Becomes' very dense, wet, light grayish brown,
\ Clayey, fine SANDSTONE /
BORING TERMINATED AT 32 FEET
Figure A-2 Log of Boring BS 2, page 1 of 1
>-'" 1-", UJ~ H. 0::"" (l)LL ;:)1-Z UJ • I-z C)~ (l)UJ ~I-0:. ~"" :E:z 0 C, U
-"
.
113.5 7.9
109.8 . 1.5
KSDS
I SAMPLE SYMBOLS D ... SAMPLING UNSUCCESSFUL
~ ••• DISTURBED OR BAG SAMPLE
(] ••• STANDARD PENETRATION TEST •••• DRIVE SAMPLE (UNDISTURBED)
~ ••• CHUNK SAMPLE ~ ••• WATER TABLE OR SEEPAGE
I NOTE: THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE
DATE INDICATED. IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
I
~ROJECT NO 05333-12-01
II DEPTH SAMPLE
IN I FEET
NO.
0:: >-IJJ (!) I-o <I: ...J :3 o Cl :J: Z I-::J H 0 ...J 0:: (!)
SOIL
CLASS
(USCS)
BORING BS 3
ELEV. (MSL.,.I-) ----=.4..:..7 __ DATE COMPLETED 5/9/94
EQUIPMENT B-61 MOBILE DRILL
MATERIAL DESCRIPTION
1= 0 J ~l SM TOPSOIL -;--'l~ -I Loose, dry, medium brown, Silty fine to medium
1-2 ~B~_I~~~,l~:~I_~--~\~_S~A~N~D_w_h~h_s~a~m~e_s~m~a~I~I~~~a~v~e~I~~~d~_~li~tt~k~ro~o~tl~e~b~_~f 23
-11 -I SM TERRACE DEPOSIT -
I-4 -:j .t'I_ ~;~~m dense, moist, dark reddish brown, Silty fine ~
I: 6 ~ BS3-2 ~1"""'~:~:-4-f:-,.-t!--l--~ _________________ , __________ ----.... -----_1--_3_9~_,"-,---+_--I
!-_ ,'l'-t -I Becomes dense, moist, medium brown, Silty SAND
oj SC with trace of clay
11= 8 = :t (f:
I: 10 = BS3-3 IrIlVf-,...-:--i, /-:1--,:--1_ -+---+ - - -;e~~~;s ~~~t-;r~;i~; ~r~~~,-~l~;e; ~~~~-t~ -S~~;y--!-31
t-12 _ V/_, CLAY "" o SC-CL I~ 14 = 1.J»:.n-/~':'-t--+ __ -\-~ ,
I
'" 16 -BS3-41~} ---;e~~~e~-~I~y~~~i~~~~~~-------------------50
~ -v.;(> SC I-f-,-~~ -Becomes very wet to saturated t-18 -V:. (: / ~ }~>:-
-
110.8 18.8
I !--/l'j~ I-
20 -///"/ '" BS3_5Ir1lm'~~+---+----------------~--~-~-8-7-~-~~-4
!-_ SANTIAGO FORMATION ~
I ,.. 22 -Becomes very dense, wet, Clayey SILTSTONE
~ _ ~ ML
I-24 -
It--BS3-6 •
I-26 -
-I: 28 =
- -
I I-30 -BS3-7 -=
I---
!-32
-Water table at 23 feet
-Becomes Sandy SILTSTONE
-Becomes Clayey SILTSTONE
-
-
I-
~
I-
~
-
~
-
-
50/6" 12Q.8 13.6
50/5"
I BORING TERMINATED AT 32 FEET
~-::---:-w-~~~_~""",,"-----I------L---I.o---J
Figure A-3 Log of Boring BS 3, page 1 of 1 KSDS I SAMPLE SYMBOLS D ... SAMPLING UNSUCCESSFUL IJ ... STANDARD PENETRATION TEST .... DRIVE SAMPLE (UNDISTURBED)
~ ••• DISTURBED OR BAG SAMPLE ~ ... CHUNK SAMPLE ~ ... WATER TABLE OR SEEPAGE
I NOTE: THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE
DATE INDICATED. IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDI.TIONg AT OTHER LOCATIONS AND TIMES.
I
IROJECT NO 05333-12-01
I
0:: BORING BS 4 > lLJ . ZlLJ""'
(!) l-0 <I: °u .
DEPTH SAMPLE ..J :3: SOIL I;jZG:
IN 0 Cl CLASS <I:~'
NO. :J: Z ELEV. (MSL.) 47 DATE COMPLETED 5/.9./.94
FEET I-:::J (USCS) 0:: (/)'(/)
I H 0 I-H:3:
..J 0:: lLJ(/)O
EQUIPMENT B-61 MOBILE DRILL zlLJ..J (!) ~o::e'
MA TERIAL DESCRIPTION
I i-0 :,1. ~'l SM TOPSOIL .
r--:'1·1-"1-Loose, dry, medium brown, Silty fine SAND r -2 -1 1-, TERRACE DEPOSITS -
I BS4-1 SM 37 --:'1 t-I-Medium dense, moist, orangish brown, Silty, fine to .,..
f-4 -medium SAND f-
:1· ."1-
I
f--[ rt:'. f-
BS4-2 10
f-6 ---------------------------------------
i---Loose, to medium dense, moist, very light grayish '-
--SP brown, fine SAND, cohesion less .
I :-8 -------,... ----.-
· -
f-10 -BS4-3 f'" -f-
I
32
I--f-
-12 ----I-'
· --Becomes very wet to saturated ---f--I ---~ 14 ---Water table at 14 feet I---
:-------------------------------------------BS4-4 · -SW Becomes medium dense, saturated, light orang ish 74
:-16 --
I : 1· '1-"1-
, ,.
\ brown, fine to coarse SAND with some fine to I
-"1"-i -, \ medium .sravel ' f-~-----------------------------------,
18 -:'i t-I-SM Becomes very dense, light orangish brown, Silty fine '-
I -SAND -:J. -"I-20 -BS4-5 • :1"-1-, -50/3" -::f:~: :t I 22 -:rkf SANTIAGO FORMATION -Very dense, wet, very light greenish brown, Silty fine -::f:~::t SANDSTONE -
24 -::t*:f -
I .' 'f' -BS4-6 ~ ':[: :'t -Becomes gray, mottled with purplish red -
SM 50/5"
26 -::t*:[ -
" 'f' -':f: :'t -
28 -::t*:f -
-::f:~: :t -
30 -BS4-7 • ::t*:f i-
::f:~\ 50/5" -i-, :r ' , ,
32 .... ",.'
BORING TERMINATED AT 32 FEET
I
I
I. Figure A-4 Log of Boring BS 4, page 1 of 1
> ""' I-lLJ~ H""' (/) . 0::'''"'
zu. :::JI-lLJ • I-Z Cl~ (/)lLJ HI->0.. Oz "
0::""' 1:0
Cl c:J
' 100.2 3.7
114.1 15.5 '
116.2 15.a
KSDS
I SAMPLE SYMBOLS D ... SAMPLING UNSUCCESSFUL
~ ••• DISTURBED OR BAG SAMPLE
[] ... STANDARD PENETRATION rEST .... DRIVE SAMPLE (UNDJSTURBED)
IiiJ ••• CHUNK SAMPLE ~ ••• WATER TABLE OR SEEPAGE
I NOTE: THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE
DATE INDICATED. IT IS NOT WARRANTED TO BE REPRESENrATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
I
lROJECT NO. 05333-12-01
I
I
DEPTH
IN
FEET'
II-I-0
SAMPLE
NO.
>-i~ (!) 0 ....I SOIL a CLASS :I: i I-(USCS) H ....I
~'l
SM
BORING BS 5 ~UJ~ >-" 14" UJ~ . HUI-I-Zu.. (I) • 0:: ......
<I: <1:" zu.. ::JI-
ELEV. (MSL.) 44 DATE COMPLETED 5/9/94 '0:: I-(I) UJ' ..,.Z
1-(1);3; C~ (I)UJ 'UJ~O HI-
EQUIPMENT B-61 MOBILE DRILL 'a" Oz zUJ....I ~ ...... :1:0 ~o::e c U
MA TERIAL DESCRIPTION
TOPSOIL
Loose, dry, light brown, Silty fine to medium SAND I
with rootlets I-20
TERRACE DEPOSITS '""'
Loose to medium dense, moist, dark reddish brown,
Silty fine SAND' -
--Becomes moist to wet, orangish brown
-Becomes dense, wet at 5 feet 29 113.5 7.0
-FigUre A-5 Log of Boring BS 5, page 1 of 1
-
l-
I-
I-
I-24 I-
-
-
I-
15.0
KSDS
I SAMPLE SYMBOLS 0 ... SAMPLING UNSUCCESSFUL'
~ ••• DISTURBED OR BAG SAMPLE
(J •.• STANDARD PENETRATION TEST •••• DRIVE SAMPLE (UNDISTURBED)
iJ ... CHUNK SAMPLE ~ ••• WATER TABLE OR SEEPAGE
I NOTE: THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE ,SPECIFIC BORING OR TRENCH LOCAtION AND AT THE
DATE INDICATED. IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTH~R LOCATIONS AND TIMES.
·1
lROJECT NO 05333-12-01
I DEPTH IN SAMPLE I FEET NO.
~ >-UJ (!) I-o <I: ...J :3: o 0 :J: :z I-::J H 0 ...J ~ (!)
SOIL
CLASS
(USCS)
BORING BS 6
ELEV. (MSL.,.L..) ----=-48:::.-__ DATE COMPLETED 5/10/94
EQUIPMENT B-61 MOBILE DRILL
MA TERIAL DESCRIPTION 11-_ 0 _ :.1.1:1-.. ,._.~ _, SM TOPSOIL
1 ~ t Loose, dry, light brown, Silty, fine to medium SAND
1-42 --BS6-1 I :l·ll .,._i -, TERRACE DEPOSIT
1 ~ Medium dense, moist, orangish brown, Silty, fine to
30 I-
--:j i .1-medium SAND
II-I-6 -BS6-2 • :·1· -t.-i-SM -36 -~ 11 -I -
I--J t· t· -
109.1 7.5
I: 8_ -:1-1l --~l -
10 -~·~·J~-+----4--------------------------------------~---r----~--~
I -BS6-3 l:··· -25 Becomes moist to wet, light orangish brown, fine I-
SAND, cohesionless I-12 --_ '"'-SP I---_ _ '"'-
I I-14 -
I--I -
BS6-4 -48
I I-16 - - -
I--
-
-
-18 -I-w'--<>--l-+-----t --------------------------------------1------/-----1-----1
I - --. SW Becomes very wet, fine to coarse SAND with som~ I-
rr.--,......-r--,-f---+------+ ___ s!fl..a~ _g!:a'y~l_ a.!l~ !~~ !fl_e~i.!l~_ c_o!>~l~s ___________ ,..1-_-/----1--~
20 -BS6-5 :1.i:l-85
I
I--li -I SM ~x~r:es very dense, wet to saturated, Silty fine l-
I-22 -:j t.!_ l-
I---.1. i.-I_ -
I-24 --·,-_i -I ~ -
I 1 -Water table at 24 feet I-_ ~:~L~_~+-__ -+ ________________________________ ~ ____ -+~ __ +-~~~~
BS6-6 • -:f:~:-t SOlS" 114.6 14.0 -26 -:-:t:~::-[ SANTIAGO FORMA nON -, [ SM Very dense, wet to saturated, light grayish brown,
I -::f:~::t Silty fine SANDSTONE -
28 -.:t:~:.[. -
I--:. -~-:~: I-
I I-30 -BS6-7
I--
-t---t-::t:~::f: -:r:~: -~ :.[ ~ ~~:~
1-50/6"
I-
I-32
I BORING TERMINATED AT 32 FEET
~~~~~~--~~ Figure A-6 Log of Boring BS 6, page 1 of 1 KSDS I SAMPLE SYMBOLS D ... SAMPLING UNSUCCESSFUL IJ ... STANDARD PENETRATION TEST •••• DRIVE SAMPLE (UNDISTURBED)
~ ... DISTURBED OR BAG SAMPLE ~ ... CHUNK SAMPLE ~ ... WATER TABLE OR SEEPAGE
I NOTE: THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT-THe
DATE INDICATED. IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
I
lROJECT NO 05333-12-01
I DEPTH SAMPLE
IN I FEET
NO.
>-(!) o ...J o iE I-f ...J
0:: lIJ I-~ SOIL ~ CLASS 15 (USCS)
0:: (!)
BORING BS 7
ELEV_ (MSL. . .I...) ----:;4.:::...8 __ DATE COMPLETED 5/10/94
EQUIPMENT B-61 MOBILE DRILL
MA TERIAL DESCRIPTION
I
I-0 _ J 1_-1_ TOPSOIL '.l'-,~ -, SM .~ Loose, dry, medium brown, Silty, fine to medium
I
2 -:1-I-"\-\'---=S::,.A.=N.,;.:D=--______________ ---1!
-l.1 -, TERRACE DEPOSIT
4 {SM Loose to medium dense, moist to wet, dark orangish
I-
"-I--:1 'I-brown, Silty, fine to medium SAND
I: 6 ~ BS7 -1 Irl+--_:-:-:.,L,~'...:._'-+-+----+ - - -;e~~~~ -:e~, -o~~n-g~s~ ~~;:n~ ~i~~ ~o-~~~i~~ -S~~~~ -"-11
cohesionless I---SP
II-8 =
10 = BS7-2 J:-,~, ,-
It-12 -SP
I--_-
I
I: :: = BS7-3 [: ... :.
- -
18 -
-Becomes very dense, moist, light orang ish brown,
fine SAND, cohesionless
-Becomes fine to medium SAND
-
-
f-71
"-
"-
I-
-
,-
-
-
-
-
43
105.4 3.5
50/611 100.3 4.4 I-
I 20 ~ BS7 -4 • -:~, -,~ ~
I--:_ -
"-
"-I f--22 -:~ _-
I--, --I-24 --_ I-
II--BS7 -5 1r1:_0:-,: ",':<:=:==SW==~, - --;e~~~e~ -v~;y-~;t -t~ ~a~~r~t~~,-f~;e -t~ -c~:r;e -S-;~~ -~t---6-7---i---+---I
26 -~ :1, I-"\-
...L SM Becomes light grayish brown, Silty, fine to medium I I--,'j,-1 -I _ \~ - -'Yi.!I!. ~.o.,!11_e -s!.ll~!! j!:.a'y~I_ - - - - - - - - - - - - - - -....... - -/ "-
28 -_ i ~_I-= SAND I-
~ ~~rt-r_--_i'-~-~W~a~t~er~ta~b~le~at~2~8~fe~e~t-----------------------rr_---t~--;----i -~:j. 1-"\-
I I-30 -.. J SANTIAGO FORMA nON "-
I-BS7-6 ,. II -, SM Very dense, very wet to saturated, very light grayish 1-50/511' 106.8 12.8 -:11-1-brown, Silty fine SANDSTONE .
I-32 ~----++~~-+----1_---------------------------------~----_r--~+_----~--~
I BORING TERMINATED AT 32 FEET
I~-:---=-'--I-~~~_~---'--_~~-I....--..J Figure A-7 Log of Boring BS 7, page 1 of 1 KSDS I SAMPLE SYMBOLS D ... SAMPLING UNSUCCESSFUL [J ... STANDARD PENETRATION TEST •••• DRIVE SAMPLE (UNDISTURBED)
~ ••• DISTURBED OR BAG SAMPLE ~ ••• CHUNK SAMPLE ~ ••• WATER TABLE OR SEEPAGE
I NOTE: THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH, LOCATION AND AT ·THE
DATE INDICATED. IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER 'LOCATIONS AND TIMES.
I
IROJECT NO 05333-12-01
II DEPTH
0:: BORING BS 8 >-lLJ ZlLJ'" >-.;..
(!) .... 0 <I: °u . ....'" lLJ~
....I ::3: SOIL HZ .... H. 0::""
IN SAMPLE 0 Cl CLASS .... <I:u. (J)u. :l '
NO. ::c Z ELEV. (MSL.) 20 DATE COMPLETED SL10L94 ,<I: .... " Z. ........ n FEET .... :l (USCS) I=(J)~ lLJ(;.) (J)Z
H 0 lLJHO ' Cl • HlLJ
....I 0:: EQUIPMENT B-61 MOBILE DRILL z(J).;J >-Q. 0 ....
(!) lLJlLJa:I 0::"" ~z ,0 Q. 0::"" C (.)
MATERIAL DESCRIPTION
If 0 :-1. 1_-1_ SM TOPSOIL -'-dol Loose to medium dense, dry to damp, light grayish -
-2 -L :'f+:t brown, Silty fine SAND .
I~ BS8-1 'T SANTIAGO FORMATION .,..50/5" -:·f· ·:f ~
4 " 'f' Very dense, moist to wet, light gray, Silty fine to -·:f: :·f medium SANDSTONE "'" , .,
I: -• ::t:~::f -
BS8-2 SM 6116" 105.3 9,i
6 -... ~ ... -::f:~::~: -" , -, ::t:~::f :
I 8 -"f' ,t -, ., 'T I--:·t+ .:~ -
" 'f' f-10 -BS8-3 t-: ::f: ::f r-
I "j' 50/3" -::f: ::f: i-..... ~.·r·
l-12 -"f' "t -: ... ~.: - -'r "f -
I .' 'f' r-14 -::f: ::f -
'--BS8-4 -:rkf -.+ .. ~. toe .. SO/I"
I -16 -::f:·::f: -
f-··~:j::r:
BORING TERMINATED AT 17 FEET
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I Figure A-8 Log of Boring BS 8, page 1 of 1 KSDS I SAMPLE SYMBOLS 0 ... SAMPLING UNSUCCESSFUL IJ ... STANDARD PENETRATION TEST •••• DRIVE SAMPLE (UNDISTURBED)
~ ... DISTURBED OR BAG SAMPLE ~ ... CHUNK SAMPLE ~ ., •• WATER TABLE OR SEEPAGE
I NOTE: THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION' AND AT THE
DATE INDICATED. IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCAlIONS AND TIMES.
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IPROJECT NO 05333-12-01
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DEPTH
IN
FEET
I-0
I--
-2 -
-
I-4 -
I--
I-6 -
I--
8 -
-
10 -
-
12 -
-
14 -
-
16 -
-
-18 -
-
20 -
-
22 -
-
24 -
-
26 -
I):: > w (!) I-0 <t: ..J 3 SOIL SAMPLE 0 Cl
NO. :x: z CLASS
I-:;:) (USCS) H 0 ..J I)::
(!)
)',l 'd'l SM
BS9-1 :l,'l l~ 'I
:'1 t-[-
BS9-2 I-tr::-SM
:'1 t-[,
:1-l :d-I
BS9-3 l:'" -
------, -, -----SP 1'--':-.-BS9-4 --------~ ------, --
BS9-5 I:
:1-'l li -I SM
:'1 r [-
:1-l
BS9-6 • li -I
:'1 t,[-
BORING BS 9 zl.tJ"" °u • HZI-1-<t:lJ..
ELEV. (MSL.) 49 DATE COMPLETED 5,(llL94' ~I-~ 1-(/);3; WHO
EQUIPMENT B-61 MOBILE DRILL _ z(/)..J W'~al a.. ""'
MATERIAL DESCRIPTION
TOPSOIL ;..
Loose to medium dense, dry, medium brown,' Silty
fine to medium SAND " .I 17
TERRACE DEPOSIT -
Medium dense, moist, reddish brown, Silty fine to I-
medium SAND --Becomes orangish brown 37 -
-
--
--------------------------------------
Becomes dark orangish brown, fine to medium SAND, 29
I-
cohesionless -
;..
-
'--Becomes dense to very dense, very light orang ish 71
brown, fine to medium SAND with few little gravel, -
cohesionless I-
-Water table at 18 feet
I-
I-,
"-
50/3"
SANTIAGO FORMATION -
Very dense, moist to wet, very light grayish brown, -Silty fine SAND
I-
1-50/4"
I-
BOTTOM OF HOLE AT 27 FEET
-I
I Figure A-9 Log of Boring BS 9, page 1 of 1
> "" ,I-"" wX H 1)::""' (/). 'ZlJ.. :;:)1-w· I-Z Cl~ (/)W H ... >0.. Oz
1)::""' Eo
Cl u
101.9 4.2
-,
KSDS
I SAMPLE SYMBOLS D ... SAMPLING UNSUCCESSFUL
~ ••• DISTURBED OR BAG SAMPLE
IJ ... STANDARD PENETRATION TEST •••• DRIVE SAMPLE (UNDISTURBED)
~ ••• CHUNK SAMPLE ~ ••• WATER TABLE OR SEEPAGE '=' . -. -
I NOTE: THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE ,SPECIFIC BORING,OR' TRENCH LOCATION AND AT THE
DATE INDICATED. IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
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'ROJECT NO 05333-12-01
I DEPTH SAMPLE IN I FEET NO.
Q:: >-w (!) I-o <t: ..J ::I o 0 :J: Z I-::::l H 0 ..J Q:: (!)
II-I-0 :.1."'-"1-
SOIL
CLASS
(USCS)
SM -l1-, - 2 -~~.~~~~--~
I ~SI0-1 :1· ~l -ll-,
4 -:j {'I-
I r-)3S1 0-2 r :.J. f'-i-6 -'1·1-,
L 1-{
SM
BORING BS 10 : zw...... >-0u' 1-...... Hzl-H. I-<t:1J.. (J)IJ..
ELEV. (MSL.,L.) --=.4.:.,8 ___ DATE COMPLETED 5/11/94 ~I-(},' ffi • -- -I-(J)::I .OU. WHO
EQUIPMENT B-61 MOBILE DRILL • ffiffii6' ~!b -------=--=:..=..-'-==-"=:=....;;;"":', =~------. Q. Q::", 0
MA TERIAL DESCRIPTION
TOPSOIL -
Loose to medium dense, dry to damp, medium brown, rf---,-,,.---f,---j-----I
Silty fine to medium SAND ,I 43
TERRACE DEPOSIT ~
Medium dense to dense, moist, dark orang ish brown, r
Silty, fine to medium SAND
-Becomes light orangish brown, Silty fine SAND r 14
8 :1. l -1
'-= BSIO-3 ~ :'j f t--
-~l -
-10 )3SI0-4 ""'_'='-....... 'I'-'-f-+ __ -+ - - -;e~~~e~ ~~~s~,-~~e-;~~~,-c-o~;s;o~;e~s-- - - - - - - --l-r-4"-:'7--+-1-0-1.-0~-S-.3---'1 ~ 12 = SP ~
r
r I 14 -
r -~~~+--~-----------------------------------~--I--~-+----~~~
6 BSI0-Sll ~l.Y: Becomes very wet to saturated, Silty, fine to coarse _ 39 1:-1 --ll -I = SAND
I--:j t. t-SM
'-18 --.j.1.-,_
-
-
-Water table at 16 feet -I, -)-t-I
20 =~SI0-6W:~::ft7:~:=~~~----r---S-A-NTIA---GO---F-O-RMA---TI-O-N------------~--~_~S-0/-3-1I+-11~9~.2;-1~2-.4~
I ' '1' [ Very dense, moist, light grayish brown, Silty fine
.' 22 -:r1::t SM SANDSTONE -. -¥~ ~
I r-24 -:;f:~::t: r-
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I--BSIO-71::~t~~~:f -Becomes moist to wet r SO/4"
":' 26 -:,r,~,:t r-.. [:~:.
BOTTOM OF HOLE AT 27 FEET
I~~~~~~----~~ Figure A-l0 Log of Boring BS 10, page 1 of 1 KSDS
I SAMPLE SYMBOLS D ... SAMPLING UNSUCCESSFUL
~ ••• DISTURBED OR BAG SAMPLE
IJ .,. STANDARD PENETRATION TEST •••• QRIVE SAMPLE (UNDISTURBED)
~ ••• CHUNK SAMPLE I ... WATER TABLE OR SEEPAGE
I NOTE: THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND'AT THE
DATE INDICATED. IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
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IROJECT NO 05318-12-01
IloEPTH
0: BORING B 3 > W ZW ...... > '"' (!) I-0 <I: °u • 1-...... UJ~
SAMPLE -l :::I SOIL HZI-H. 0::'-'
IN 0 Cl CLASS ~<I:'t ~u. :::;)1-
Z z ELEV. (MSL.) 46 DA TE COMPLETED 5/4/94 NO. I-:::;)
0:: I-CJ) . UJ' I-z II FEET (USCS) I-CJ):::I Cl~ ~UJ H 0 WHO -l 0: EQUIPMENT B-61 MOBILE DRILL zCJ)-l >Il. 01-
(!) UJwal 0::'-' x::Z 0 Il.a::...., Cl u
MA TERIAL DESCRIPTION
II 0 :·I·ll -J"t "I
SM TOPSOn. I-
Loose,dry to damp, light brown, Silty fine to medium
II 2 -: 1· -"I-~ SAND with rootlets / B3-1 54 116.2 4.4
-11 "I TERRACE DEPOSITS -SM Medium dense, damp, medium brown, Silty fine to
4 -:~ .[·1" medium SAND . -
II -"i -t"j --------------------------------------B3-2 I :1. 1'"1-Becomes loose, very moist to nearly saturated, 8
6 -11 "I -
SM medium grayish brown, slightly Silty, fine to medium
II -:1 .[·1" SAND -
8 -"1 -t.i ,
"f':'r . " --::f:l::f SANTIAGO FORMATION -.
11 10 -
' , , ~ Very dense, very moist, greenish gray, Clayey, fine to • ::f:~::t medium SANDSTONE -123,3' B3-3 :tJ.:f SC -Water table stabilized at 9.5 feet 50/411 11..8
-" '1" -
I f 12 -<f: :·t -:r~::f
t--" 'f' ~ 'r :'t -14 -::t:j:=f -Scattered gravels from 13 to 15 feet l-
I l -'r B3-4 .. ::t:.::t: SM ___ ~e:~~e: _v:.ry_l~g~: ~r!~!~ ~~!: ~i:~ ~~~?~:~~""_ -50/6"
I-16 -::f:~::t Becomes slightly Silty fine to coarse SANDSTONE -
It
:r~':f -" 'f' -
18 -
-=f: :'t SP-SM ::t*=f -
.' 'f' I -'r >t -
to :~:. , , ,
I-20 . ,
BORING TERMINATED AT 21.5 FEET
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I Figure A-3 Log of Boring B 3, page 1 of 1 PS II SAMPLE SYMBOLS D ... SAMPLING UNSUCCESSFUL IJ ... STANDARD PENETRATION TEST •••• DRIVE SAMPLE (UNDlSTURBED)
~ ... DISTURBED OR BAG SAMPLE iJ ... CHUNK SAMPLE ~ ... WATER TABLE OR SEEPAGE :=' . rOTE: 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.
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Project No. 05333-12-01
June 23, 1994
APPENDIXB
LABORATORY TESTING
Laboratory tests were performed in accordance with generally accepted test methods of the
American Society for Testing and Materials (ASTM) or other suggested procedures. Selected
samples were tested for their maximum dry density and optimum moisture content, iIi-place density,
moisture content, gradation and consolidation characteristics. The results of these tests ate
summarized on Tables B-1 and B-II, and Figures B-1 through B-4. The results of in-place density
and moisture content are shown on the boring logs, Figures A-I through A-lO, and the off-site
boring A-3 (Boring No. B-3).
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Project No. 05333-12-01
June 23, 1994
TABLE B-1
SUMMARY OF DIRECT SHEAR TEST RESULTS
Dry Moisture Unit
Density Content Cohesion
Sample No. (pet) (%) (pst)
BS1-4 101.8 7.0 0
BS4-5 114.1 15.5 880
TABLE B-II
Angle of
Shear
Resistance
(degrees)
41
37
SUMMARY OF LABORATORY MAXIMUM DRY DENSITY
AND OPTIMUM MOISTURE CONTENT TEST RESULTS
ASTM D1557-91
Sample No. Description
BS10-3 Brown, Silty, fine to medium SAND
Maximum
Dry Density
(pet)
131.0
Optimum
Moisture Content
. (% Dry Weight)
9.7
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PROJECT NO. 05333-12-01
GRAVEL SAND
COARSE I FINE ~OARSEI MEDIUM FINE
U. S. STANDARD SIEVE SIZE
1-1/2" 110 If so 50
S" S/4" S/8" 4 20 40 60 100 200
100 II -rr ..,... ~ ~~ I I
I 1Io~ I I I
I ~I I I
90 I ~, N
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I I ~ I
80 " I I ~ I I
I I i\ :~ I
l-I I 1\ I ::x: 70 \ " I , (.!) I I I H W I I I I
:3: 60 I I I I
)0-I I
" \' I
10 I I I
Il:: I I 'II I
w 50 1\ I \ z I I \ I
H I I
LL I ~ I I I
I-40 :~ z I I I
W U I I \ I
Il:: I I I
W 30 ~ \ a.. I I I I
I I I I
20 I I I I
I I I ~' I
I I I I
I I I
10 "'" I I I
I I I
0 I I I I
10 1 0.1
GRAIN SIZE IN MILLIMETERS
SAMPLE Depth (ft) CLASSIFICATION
• BS2-4 15.0 (SM) Silty fine to medium SAND
III BS4-4 15.0 (SP) Fine to medium SAND
A BS6-3 10.0 (SP) Fine to medium SAND w /silt
GRADA TION CURVE
STORM DRAIN SYSTEM
ASSESSMENT DISTRICT
CARLSBAD, CALIFORNIA
KSDS
SILT Oll CLAY
, .
' .
0.01 0.001
NAT W(: LL PL PI
.. ..
..
Figure B-1
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PROJECT NO. 05333-12-01
GRAVEL
COARSE I FINE
1-1/2" 3" 3/4" 3/8" 100 II I
I
90 I
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80
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l-I :J: 70 t!) I H UJ I :3 60 I
>-I
III I
Q:! I
UJ 50 z I
H I LL I
I-40 Z I UJ I U Q:! I UJ 30 Q.. I
I
20 I
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10 I
I
0 I
10
SAMPLE Depth (ft) • BS7-6 30.0
1%1 BS10-2 ·5.0
KSDS
, ,
SAND
COARSE! MEDIUM FINE SILT OR CLAY
U. S. STANDARD SIEVE SIZE
f 110 1 30 50 20 40 60 190 2QO
Il T ~ t'i~ I I
I
I "'!p I I
I 1\ : I
I , I
I I I
N I I
I I
I I
I :~ I
I I
I I
I I , I
I I I
I I I
I I I
I I I <
I I I ..
I I I
I I \' I
I I I
" I I I'
I I I
I I I
I I
I I I
I I
I I I
I I I
I I I ,~
1 0.1 0.01 0.001
GRAIN SIZE IN MILLIMETERS
CLASSIFICATION, N"AT we LL PL PI
(SM) Silty medium SAND 12.8 -
(SM) Silty fine to medium SAND
GRADATION CURVE
STORM DRAIN SYSTEM
ASSESSMENT DISTRICT
CARLSBAD, CALIFORNIA
.-
Figure B-2
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PROJECT NO. 05333-12-01
SAMPLE NO. BSl-6
-4
-2
0 -............. !'-..... .......... ........
z r-... 0 2 H "l"-I--~ <t 0 H ..J ~ 0 (f) 4 z " 0 (.) ~ I--~ .... ~ z ~ UJ (.) -r"I
a:: 6 UJ 0-
S
10
12 0.1 1 10
APPLIED PRESSURE (ksf)
Initial Dry Density (pef) 100.2 Initial Saturation (0/0)
Initial Water Content (%) 7.7 Sample Saturated at (ksf).
CONSOLIDA TION CURVE
STORM DRAIN SYSTEM
ASSESSMENT DISTRICT
CARLSBAD, CALIFORNIA
KSDS
100
31
0.5
-
Figure B-3
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PROJECT NO. 05333-12-01
SAMPLE NO. BS5-6
-4
,-2
0 ........... ~ ~~
~
1"1"" z 0 2 H '" I-<J: C H '" ...J 0 en 4 z " 0 U
I-..-. "-z ~ ..... IJJ ..... U 0:: 6 -" IJJ 0..
e
10
12 0.1 1 10
APPLIED PRESSURE (ksf)
Initial Dry Density (pef) 116.2 Initial Saturation (0fQ)
Initial Water Content (CAl) 15.0 Sample Saturated at" (ksf)
CONSOLIDA TION CURVE
STORM DRAIN SYSTEM
ASSESSMENT DISTRICT
CARLSBAD, CALIFORNIA
--"
KSDS
I
I
':--
" ,
100
93.1
0.5
. ""
Figure B-4
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APPENDIX C
RECOMMENDED GRADING SPECIFICATIONS
FOR
STORM DRAIN SYSTEM
ASSESSMENT DISTRICT
CARLSBAD,CALIFORNIA"
Project No. 05333-12-01
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1
RECOMMENDED GRADING SPECIFICATIONS
GENERAL
1.1 These Recommended Grading Specifications shall be used in conjunction with the
Geotechnical Report for the project prepared by Geocon Incorporated. The recom-
mendations contained in the text of the Geotechnical Report are a part 9f the earthwork
and grading specifications and shall supersede the provisions contained hereinafter in
the case of conflict.
1.2 Prior to -the commencement of grading, a geotechnical consultant (Consultant) shall be
employed for the purpose of observing earthwork procedures and testing -the fills for
substantial conformance with the recommendations of the Geotechnical Report and
these specifications. 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 017 agency
ordinances, these specifications and the approved grading plans. If, in the opinion of
the Consultant, unsatisfactory conditions such as questionable' soil materials, poor
moisture condition, inadequate compaction, 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 co~truction be
stopped until the unacceptable conditions are corrected.
2 DEFINITIONS
2.1 Owner shall refer to the owner of the property or the entity on whose behalf the
grading work 'is being performed and who has contracted with the Contractor to have
grading performed.
2.2 Contractor shall refer to the Contractor performing the site grading work.
2.3 Civil Engineer or Engineer of Work shall refer to the California licensed Civil
Engineer or consulting firm responsible for preparation of the grading plans, surveying
and verifying as-graded topography.
2.4 Consultant shall refer to the soil engineering and engineering geology consulting
firm retained to provide geotechnical services for the project.
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3
2.5 Soil Engineer shall refer to a California licensed Civil Engineer retained by the
Owner, who is experienced in the practice of geotechnical engineering. The Soil
Engineer shall be responsible for having qualified representatives on-site to observ~and
test the Contractor's work for confonnance with these specifications.
2.6 Engineering Geologist shall refer to a California licensed Engineering Geologist
retained by the Owner to provide geologic observations and recommendations during
the site grading.
2.7 Geotechnical Report shall refer to a soil report (including all adde~dums) which may
include 'a geologic reconnaissance or geologic investigation that was prepared
specifically for the development of the project for which these Recommended Grading
Specifications are intended to apply.
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 defmed as fills containing no rocks or hard lumps'greater than 12
inches in maximum dimension and containing at least 40 percept QY 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 tock 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 defmed
as material smaller than 3/4 inch in maximum dimension. The quantity of fines
shall be less than approximately 20 percent of the rock fill quantity.
3.2 Material of a perishable, spongy, or otherwise unsuitable nature as determined by the
Consultant shall not be used in fills.
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3.3 Materials used for fill, either imported or on-site, shall not contain hazardous materials
as defined by the California Code of R~gu1ations, 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 an~ysis of the potential
presence of hazardous materials. However, if observations, odors or soil discoloration
cause Consultant to suspect the presence of hazardous materials,. the Consultant may
request from the Owner the termination of grading operations within the affected area.
Prior to resuming grading operations, the Owner shall provide a written report to the
Consultant indicating that the suspected materials are not hazardous as defined by
applicable laws and regulations.
3.4 The outer 15 feet of soil-rock fIll slopes, measured horizontally, should be composed
of properly compacted soil fill materials approved by the Consultant. Rock fill may
extend to the slope face, provided that the slope is not steeper than 2: 1
(horizontal:vertical) and a soil layer no thicker than 12 inches is track-walked onto the
face for landscaping purposes. This procedure may be utilized" provided it is
acceptable to the governing agency, Owner and Consultant.
3.5 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 of the soil.
3.6 During grading, soil or groundwater conditions other than those ide~tified in the
Geotechnical Report may be encountered by the Contractor. The Consultant shall b~
notified immediately to evaluate the significance of the unanticipated condition.
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; sttunps, brush, vegetation,
man-made structures and similar debris. Grubbing shall consist of-removal of stuinps,
roots, buried logs and other unsuitable material and shall be perfotmed in areas to be
graded.' Roots and other projections exceeding 1-112 inches in, diameter shall be
removed to a depth of 3 feet below the surface of the ground. Bortow areas shall be
grubbed to the extent necessary to provide suitable fill materials.
4.2 Any asphalt pavement material removed during clearing operations should be properly
disposed at an approved off-site facility. Concrete fra~ents which are free of
reinforcing steel may be placed in fills, provided they are placed in accordance with
Section 6.2 or 6.3 of this document.
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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 featqres 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 (horizonta1:vertical),
or where recommended by the Consultant, the original ground should be benched in
accordance with the following illustration.
NOTES:
TYPICAL BENCIDNG DETAIL
, NO 'sc.:.~
(1) Key width "B" should be a minimum of 10 feet ~ide, or
sufficiently wide to permit complete coverage with th~compaction
equipment used. The base of the key should be gradeci horizontal,
or inclined slightly into the natural slope.
(2) The outside of the bottom key should be below the topsoil or
unsuitable surficial material and at least 2 feet into dense formational
material. Where hard rock is exposed in the bottom of the key, th~
depth and configuration of the key may be modified as approved 'by
the Consultant.
.....
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4.5 After areas to receive fill have been cleared, plowed or scarified, the surface should
be disced or bladed by the Contractor until it is uniform and free from large' clods.
The area should then be moisture conditioned to achieve the proper moisture content,
and compacted as recommended in Section 6.0 of these specifications.
COMPACTION EQUIPMENT
5.1 Compaction of soil or soil-rock fill shall be accomplished by sheepsfoot or segfnented-
steel wheeled rollers, vibratory rollers, multiple-wheel pneumatic-tired rollers, or other
types of acceptable compaction equipment. Equipment shall be of such a design that
it will be capable of 'compacting the soil or soil-rock fill to the specified relative
compaction at the specified moisture content.
5.2 Compaction of rock fills shall be performed in accordance with Section 6.3.
6 PLACING, SPREADING AND COMPACTION OF FILL MATERIAL
6.1 Soil fill, as defined in Paragraph 3.1.1, shall be placed by the Contractor in accordance
with the following recommendations:
6.1.1 Soil fill shall be placed by the Contractor in layers that, when compacted,
should generally not exceed 8 inches. Each layer shall be spread evep!y 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 ne~ly
level lifts. Rock materials greater than 12 inches in maxinium dimensio:Q. 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 D1557-91.
6.1.3 When the moisture content of soil fill is below that specified by the Consultant,
water shall be added by the Contractor until the moisture content is in the 'range
specified.
6.1.4 When the moisture content of the soil fill is above the range specified by the
Consultant or too wet to achieve proper compaction, the soil fIll shall be aerated
by the Contractor by blading/mixing, or other satisfactory methods until the
moisture content is within the range specified.
6.1.5 After each layer has been placed, mixed, and spread evenly, ,it shall be
thoroughly compacted by the Contractor to a relative compaction of at least 90
percent. Relative compaction is defined as the ratio (expressed in percent) Of
the in-place dry density of the compacted fill to th~ maximum laboratory dry
density as determined in accordance with'ASTM D1557-91. Compaction shall
be continuous over the entire area, and compaction equipment shall make
sufficient passes so that the specified minimum density has been achieved
throughout the entire fill.
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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 oveJ;"-built by
at least 3 feet and then cut to the design grade. This procedure is considered
preferable to track-walking of slopes, as described in the following paragraph.
6.1.8 As an alternative to over-building of slopes, slope faces· may be back-rolled willi.
a heavy-duty loaded sheepsfoot or vibratory roller at maximum 4-foot fill height
intervals. Upon completion, slopes should then be track-walked with a D-8
dozer or similar equipment, such that a dozer track covers all slope surfaces at
least twice.
6.2 Soil-rock fill, as defined in Paragraph 3.1.2, shall be placed by the Contractor in
accordance with the following recommendations:
6.2.1 Rocks larger than 12 inches but less than 4 feet in maximum dimension may be
incorporated into the compacted soil fill, but shall be limited to the area
measured 15 feet minimum horizontally from the slope face and 5 feet below
finish grade or 3 feet below the deepest utility, whichever is deeper.
6.2.2 Rocks or rock fragments up to 4 feet in maximum dimension may either be
individually placed or placed in windrows. Under certain conditions, rocks or
rock fragments up to 10 feet in maximum dimension may be placed using
similar methods. The acceptability of placing rock materials greater than 4 feet.
in maximum dimension shall be evaluated during grading, as specific cases arise
and shall be approved by the Consultant prior to placement.
6.2.3 For individual placement, sufficient space shall be provided betWeen rocks to
allow for passage of compaction equipment.
6.2.4 For windrow placement, the rocks should be placed in trenches excavated in
properly compacted soil fill. Trenches should be approxnnatelY 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 mayalso be placed
utilizing an "open-face" method in lieu of the trench 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.
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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 defmed in Section 3.1.3, shall be placed by the Contractor in accordance
with the following recommendations:
6.3.1 The base of the rock fill shall be placed on a sloping surface (minjmum 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 buildilp does not
develop. The subdrains shall be permanently connected to controlled drainage
facilities to control post-construction infiltration of water.
6.3.2 Rock mls shall be placed in lifts not exceeding 3 feet. Placement shall be by
rock trucks traversing previously placed lifts and dumping at the edge of the
currently placed lift. Spreading of the rock fill shall be by Q.azer to facilitate
seating of the rock. The rock fill shall be watered heavily during placement.
Watering shall consist of water trucks traversing in front of the current rock lift
face and spraying water continuously during rock placement. Compaction
equipment with compactive energy comparable to or greater than that of a
20-ton steel vibratory roller or other compaction equipment providing suitable
energy to achieve the required compaction or deflection as recommended in
Paragraph 6.3.3 shall be utilized. The number of passes to be made will be
determined as described in Paragraph 6.3.3. Once a rock fill lift lIas 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 D1196-64, may be performed in
both the compacted soil fill and in the rock fill to aid in determining tlle nmnber
of passes of the compaction equipment to be perforIiled. 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 me 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 nU}llber 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.
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6.3.5 Test pits shall be excavated by the Contractor so that the Consultahtcan st~te
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 fmes into the rock fill from ov~rlying
soil fill material, a 2-foot layer of graded filter material shall be placed above
the uppennost lift of rock fill. The need to place graded filter material below
the rock should be determined by the Consultant prior to commenting grading.
The gradation of the graded filter mater.ial will be determined at the time the
rock fill is being excavated. Materials typical of the rock fill should be
submitted to the Consultant in a timely manner, to allow design of the graded
fIlter prior to the commencement of rock fill placement.
6.3.7 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 petfonn 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 perfonned within that interval. In addition, a minimum of one field
density test shall be perfonned for every 2,000 cubic yards of soil or soil-rock fill
placed and compacted.
7.2 The Consultant shall perfonn random field density tests of the ,cbmpacted 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 perfonned 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 be,eil 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. TheConsultant
shall request the excavation of observation pits and may perfonn 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 perfonned, plate bearing tests will be
perfonned randomly on the surface of the most-recently placed lift. Plate bearing tests
will be perfonned to provide a basis for expressing ·an opinion as t.O 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.
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7.4 A settlement monitoring program designed by the Consultant may be conducted iIi
areas of rock fill placement. The specific design of the monitoring program shall be
as recommended in the Conclusions and Recommendations section of tl1e project
Geotechnical Report or in the final report of testing and observation services performed
during grading.
'1.5 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 D1556-82, Density of Soil In-Place By the
Sand-Cone Method.
7.6.1.2 Field Density Test, Nuclear Method, ASTM D292~-~1, Density of
Soil and Soil-Aggregate In-Place by Nuclear Methods (Shallow
Depth).
7.6.1.3 Laboratory Compaction Test, ASTM D1557-91, Moisture-Density
Relations of Soils and Soil-Aggregate Mixtures Using lO-Pound
Hammer and 18-Inch Drop.
7.6.1.4 Expansion Index Test, Uniform Building Code Standard 29-2,
Expansion Index Test.
7.6.2 Rock Fills:
7.6.2.1 Field Plate Bearing Test, ASTM D1196-64 (Reapproved 1977)
Standard Method for Nonrepresentative 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 Contractor shall properly grade all excavated surfaces to
provide positive drainage and prevent ponding of water. Drainage of surface water
shall be controlled to avoid damage to adjoining properties or to flhished work on the
site. The Contractor shall take remedial measures to prevent erosion of freshly graded
areas until such time as permanent drainage and erosion control features have been
installed. Areas subjected to erosion or sedimentation shall be properly prepared in
accordance with the Specifications prior to placing additional fill or structures.
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.
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9 CERTIFICATIONS AND FINAL REPORTS
9.1 Upon completion of the work, Contractor shall furnish Owner a certification· by' the
Civil Engineer stating that the lots and/or building pads are graded to with4l 0.1 foot
vertically of elevations shown on the grading plan and that all tops and toes of slopes
are within 0.5 foot horizontally of the positions shown on the grading plans. After
installation of a section of subdrain, the project Civil Engineer should survey its
location and prepare an as-built plan of the subdrain location. The project Civil
Engineer should verify the proper outlet for the subdrains and the Contractor should
ensure that the drain system is free of obstructions.
9.2 The Owner is responsible. for furnishing a final as-graded soil and geologic report
satisfactory to the appropriate governing or accepting agencies. The as~graded report
should be prepared and signed by a California licensed Civil Engineer experienced in
geotechnical engineering and by a California Certified Engineering Geologist,
indicating that the geotechnical aspects of the grading were perfotIhed insubstantial
conformance with the Specifications or approved changes to the Specifications.
GCOCOI;I IDcorporatcd Form. 'Revision date: 08193