HomeMy WebLinkAbout; Leo Carrillo Ranch Ltd Geotechnical Investigation; Limited Geotechnical Investigation Leo Carrilo Ranch; 2000-04-01<::>rsioU.TAhns
LIMITED
GEOTECHNICAL INVESTIGATION
LEA CARRILLO RANCH
PHASE 2
CARLSBAD, CALIFORNIA
PREPARED FOR
KTU+A
SAN DIEGO, CALIFORNIA
APRIL 2000
GEOCON
INCORPORATED
GEOTECHNICAL CONSULTANTS
Project No. 06484-22-01
April 20, 2000
KTU+A
3916 Normal Street
San Diego, California 92103
Attention; Mr. Kurt W. Carlson
Subject: LEA CARRILLO RANCH, PHASE 2
CARLSBAD, CALIFORMA
LIMITED GEOTECHNICAL INVESTIGATION
Gentlemen:
In accordance with your authorization and our proposal No. LG-99353, dated August 11, 1999, -we
are submitting the results of our limited geotechnical investigation for the subject site. The
accompanying report presents the findings and conclusions from our study. Based on the results of
our study, it is our opinion that the subject site can be. developed as proposed, provided the
recommendations of this report are followed.
If you have any questions regarding this investigation, or if we may be of further service, please
contact the undersigned at your convenience.
Very truly yours,
GEOCON INCORPORATED
Joseph J. Vettel
GE 2104
JJV:DB:lek
(6) Addressee
Dennis Burke
CEG 1749
6960 Flanders Drive B 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 1
3. . SOIL AND GEOLOGIC CONDITIONS .........2
3.1 Undocumented Fill 2
3.2 Topsoil 2
3.3 Alluvium 2
3.4 Colluvium ; 3
3.5 Delmar Formation 3
3.6 Lusardi Formation 4
4 . GROUNDWATER 1 4
5 . GEOLOGIC HAZARDS 4
5.1 Landslides ....4
5.2 Faulting 4
5.3 Soil Liquefaction Potential 5
5.4 Tsimamis and Seiches 6
6. CONCLUSIONS AND RECOMMENDATIONS 7
6.1 General 7
6.2 Excavation and Soil Charactenstics 8
6.3 Seismic Design Critena 8
6.4 Grading 9
6.5 Foundations 10
6.6 Concrete Slabs-on-Grade :„;. 11
6.7 Lateral Loading 12
6.8 Retaining Walls 13
6.9 Pavements 13
6.10 Site Dramage and Moisture Protection 14
6.11 Foundation and Grading Plan Review 14
LIMTTATEONS AND UNIFORMITY OF CONDmONS
MAPS AND ILLUSTRATIONS
Figure 1, Vicinity Map
Figure 2, Site Plan
Figure 3, Wail/Column Footmg Dimension Detail
Figure 4, Retaining Wall Drainage Detail
APPENDIX A
FIELD INVESTIGATION
Figures A-I-A-9, Logs of Borings
TABLE OF CONTENTS (Continued)
APPENDDCB
LABORATORY TESTING
Table B-I, Summary of In-Place, Density and Direct Shear Test Results
Table B-n, Summary of Laboratory Expansion Index Test Results
Table B-EI, Summary of Laboratory Maximum Dry Density and Optimum Moisture Content
Tests Results
Table B-IV, Summary of Laboratory Resistance Value Test Results
Figure B-1, Consolidation Curve
APPENDDCC
RECOMMENDED GRADING SPECIFICATIONS
APPENDIX D
REFERENCES
LIMITED GEOTECHNICAL INVESTIGATION
1. PURPOSE AND SCOPE
This report presents the results of a Limited Geotechnical Investigation for proposed improvements to
the Leo Carrillo Ranch site located west of Melrose Drive and northwest of Leo Carrillo Way in
Carlsbad, CaUfomia (see Vicinity Map, Figure 1). The purpose of the investigation was to identify
the site geology, to observe and sample the prevailing soil and rock conditions at the site, and based
on conditions encountered, to provide recommendations relative to geotechnical aspects of
developing the property as proposed.
The scope of our limited investigation included a site reconnaissance, a field investigation, laboratory
testing, engineering analyses, and preparation of this report. The field investigation was performed on
March 28, 2000 and consisted of drilling six small-diameter borings using truck-mounted equipment
and advancing three hand auger borings at the locations indicated on the Site Plan, Figure 2. Logs of
the exploratory borings and other details of the field investigation are presented in Appendix A.
Laboratory tests were performed on selected soil samples obtained from the borings to determine
their pertinent physical properties for engineering analyses. A discussion pertaining to the laboratory
testing and results is presented in Appendix B.
The recommendations presented herein are based on analysis of the data obtained from our
reconnaissance, exploratory borings, and laboratory tests, together with our experience with similar
soil and geologic conditions in this portion of San Diego County. Significant references are included
in Appendix D.
2. SITE AND PROJECT DESCRIPTION
The Carrillo Ranch property is an irregularly-shaped area of about 10 acres at the confluence of
several creeks that drain west and south to San Marcos Creek. Slopes of the lower valley sides and an
alluvial plain in the valley bottom are included in the property. Topographic maps and aerial
photographs from our files show that little modification to the property has occurred since the early
1950's, although extensive grading and residential development is currently taking place throughout
its surroundings.
We understand that a variety of modifications and improvements are proposed for the site in order to
develop it as a City park. These included a paved parking area on the eastern slope near the entrance
road, partial reconstruction of the present equipment shed and blacksmith shop to include a new
caretaker residence, construction of new foot bridges over the creek that runs to the south of the
Project No. 06484-22-01 -1- Apnl 20,2000
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
carnage house and hacienda, repairs to the damaged swimming pool, and construction of new
restroom facilities near the pool. This work, to the extent possible, will maintain the histoncally
significant elements of the present site development.
3. SOIL AND GEOLOGIC CONDITIONS
Our field investigation indicates that six general soil and rock types underlie the site. These consist of
undocumented fill, topsoil, colluvium, alluvium, Delmar Formation, and Lusardi Formation. The
soils and rock encountered are described in detail below.
3.1 Undocumented Fill
It is apparent from stepped and benched areas in the vicinity of the stables, bams, and sheds that
natural slopes of the area have been modified by local cut and fill grading to produce some building ,
pads and roadbeds. These and other areas of diverse and limited fill can be expected on the site.
Our power auger drilling encountered fill to depths of no more than 2 feet in Boring B-2 in the
proposed parking area, and in B-3, adjacent to the existing equipment shed and blacksmith shop.
Thicker fill may be present elsewhere. Hand auger samples from near the swimming pool show that
near-surface local soils there have been reworked in construction, with sand added around at least a
part of the pool margin.
These materials consist predominantiy of plastic clays, with varying amounts of sand and some
gravel. They appear to have been locally derived form weathered claystone of the Delmar Formation
in the area. The fill is considered unsuitable in its present state for support of pavement, structures, or
additional fill, and will require removal and recompaction in areas of new development.
3.2 Topsoil
A mantle of topsoil that covered the site in its natural state has been removed in the area of the ranch
buildings, but it is found on the less-modified sloping ground elsewhere. This soil is soft to firm and
clayey, with lesser sand, and is characterized by common roots and pores. The topsoil is unsuitable
for development without remedial removal and recompaction.
3.3 Alluvium
Our power auger Borings B-5 and B-6 show that the alluvium of the valley plan is 10 to 13 feet thick
near the proposed footbridges close to the carriage house. Claystone strata of the Delmar Formation
should thus be found below the creek bed at a depth of several feet.
Project No. 06484-22-01 -2- April 20,2000
Firm, grayish brown, clayey alluvium with sa;nd in the near-surface grades to stiff, brownish gray and
yellowish brown clay with increasing sand, fine gravel, and- claystone fragments at depth. The
deposits became very moist to' wet in their lower part, where groundwater is perched above
iinpermeable Delmar Formation claystone.
Hand auger Boring HA-3, which sampled alluvium from near the creek level at the hacienda
footbridge, encountered a gray and brown mottled clay that is continually wetted by the creek and
softened by the roots of plants in the creek bed. Delmar Formation claystone was found at a depth of
about 2/2 feet below the creek level.
The properties of the alluvium beneath the valley plain make it imsuitable for support of the proposed
footbridges, but emplacement of supporting members in the immediate channel area will be feasible
only if they are founded in the formational materials beneath the alluvial clay.
Alluvial clay found in hand auger Borings HA-1 and HA-2 in the vicinity of the pool and cabaiia is
saturated from leakage of the pool and possible shallow groundwater, and is softened by abundant
root growth in the marshy environment. The possibility that this ground is naturally wetted is
suggested by the USD A 1953 aerial photographs, which there show a gap in the regular grid of
orchard frees in the alluvial plane.
3.4 Colluvium
Valley slopes of the site area are covered with a discontinuous veneer of colluvium as much as
several feet thick beneath the topsoil and above the local bedrock of the Delmar and. Lusardi
Formations. Colluvial materials encountered in power auger Borings B-2 and B-3 consist of firm to
stiff, brown to dark brown, sandy clay with a pronounced capacity to swell and shrink upon wetting
and drying.
The colluvium is not considered suitable for support of pavement or structures and should be
removed from areas where such development is planned.
3.5 Delmar Formation
Bedrock of the lower valley slopes and beneath the alluvium of the valley plain is a very stiff to hard
claystone assigned to the Delmar Formation, of Eocene age. The uppermost of this material is highly
weathered and firm to stiff, with orange to red mottling of the otherwise pale gray strata. Decreasing
weathering to fresher rock can be expected to vary in depth over the site, with the thickest weathered
profiles beneath the alluvium of the valley plain.
Project No. 06484-22-01 -3 - April 20,2000
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
Only the most intensely weathered and mottled material is unsuitable for structural support.
3.6 Lusardi Formation
Our Borings B-1 and B-2 in the area of the proposed parking lot encountered decomposed to highly
weathered, pale gray and reddish brown mottled, sandy conglomerate assigned to the Lusardi
Formation, of Cretaceous age. This material was derived from erosion of granitic rocks in the higher
hills nearby and, like the granitic rocks themselves, Lusardi Formation deposits are considered to be
very good foundation materials in their decomposed but very dense state. Excavation of more than
several feet into decreasingly weathered and hard conglomerate can in places prove to be difficult,
however.
4. GROUNDWATER
Surface flow of natural and irrigation waters in the creeks of the site and the presence of impermeable
claystone bedrock at shallow depth in the valley result in high groundwater conditions in the
alluviated area of the site. As mentioned above, a natural seep or spriiig may have existed in the area
of the pool and cabaiia, which would also contribute to the ground saturation found in our hand auger
borings. Planning of excavations to any depth in the low-lying areas will need to take this condition
into account.
5. GEOLOGIC HAZARDS
5.1 Landslides
Examination of aerial photographs in our files and review of available geotechnical reports for the
site vicinity indicate that no landslides are present in that portion of the property to be developed.
Several slides have been mapped on the higher valley slopes and hillsides of the surrounding area,
however, and one is reported to have toed out in the southeastern part of the site. These slides are
understood to have been removed or stabilized in the course of development of adjacent properties
and should pose no hazard, or otherwise impact, the proposed development.
5.2 Faulting
No active faults are known to exist at or near the site. The nearest known active fault, the Rose
Canyon, lies approximately 8 miles southwest of the site. This and other known active or potentially
active faults within a 62-mile (100-kilometer) radius of the site, and the associated maximum
probable and maximum credible earthquakes and site accelerations, are indicated in Table 1 below.
Project No. 06484-22-01 - 4 - Apnl 20, 2000
I
I
I
TABLE 5.2
DETERMINISTIC SITE PARAMETERS FOR SELECTED FAULTS
Fault Name
Distance
From Site
(miles)
Maximum Probable Event Maximum Credible Event
Fault Name
Distance
From Site
(miles)
Magnitude
Event
(mag)
Peak Site
Acceleration
(g)
Magnitude
Event
(mag)
Peak Site
Acceleration
(g)
Rose Canyon 8 5.7 0.14 6.9 0.30
Newport-Inglewood (offshore) 11 5.8 O.ll 6.9 0.22
Elsinore 22 6.4 0.08 7.1 0.12
Coronado Bank ' 23 6.3 0.06 7.4 0.14
Earthquake Valley 38 5.7 0.02 6.5 0.04
Palos Verde 42 6.2 0.02 7.1 0.05
San Jacinto 45 6.9 0.04 7.2 0.05
Chino-Central Ave 52 , 5.5 0.01 6.7 0.03
Whittier 56 5.9 0.01 6.8 0.03
Compton Thrust 62 5^8 0.01 6.8 0.04
It is our opinion that the site could be subjected to moderate to severe ground shaking in the event of
an earthquake along any of the faults listed in Table 5.2, or along other faults in the southem
Califomia and northem Baja California regions. Saturated soil conditions within the confines of the
site valley may exacerbate this shaking, as compared to better-drained developments in the
surrounding highlands.
While listing of peak accelerations is usefijl for comparison of potential effects of fault activity in a
region, other considerations are important in seismic design, including the frequency and duration of
motion and the soil conditions underlying the site. We recommend that seismic design of the
structures be performed in accordance with Uniform Building Code (UBC) guidelines which are
currentiy adopted by the City of Carlsbad.
5.3 Soil Liquefaction Potential
I
I
I
I
I
Soil liquefaction occurs within relatively loose, cohesionless sands that are located below the water
table and that are subjected to ground accelerations from earthquakes. Due to the clayey composition
of local alluvium and the dense natijre of formational materials at shallow depth, the potential for
liquefaction occurring at the site is considered low. Under the most exfreme conditions of shaking
and soil saturation, however, it may be possible to have permanent ground deformation from lurching
or failure along the creek banks of the site.
Project No. 06484-22-01 -5-April 20, 2000
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
5.4 Tsunamis and Seiches
The site is not located near the ocean or any other large bodies of water, so there is no local risk of
tsunamis or seiches.
Project No. 06484-22-01 -6- April 20,2000
I
I
I
I
I
I
I
I
I
I
t
I
I
1
I
I
I
I
I
6. CONCLUSIONS AND RECOMMENDATIONS
6.1 General
6.1.1 From a geotechnical standpoint, it is our opinion that the site is suitable for the proposed
development, provided the recommendations presented herein are implemented in design
and construction of the project.
6.1.2 Our field investigation indicates that the site is underlain by: (1) a patchy distribution of
undocumented fill throughout the area; (2) topsoil and colluvium on some valley slopes;
(3) alluvium on the valley plain; and (4) Lusardi and Delmar Formations at depth. The fill,
topsoil, colluvium, and uppermost alluvium are not adequate in their present condition for
support of settlement-sensitive structures. Accordingly, remedial grading in the form of
partial removal and recompaction will be required as discussed below.
6.1.3 Subsurface conditions observed in our borings are highly variable and they are not
expected to be uniform across the site.
6.1.4 Groundwater was encountered in Boring B-6 near the creek at a depth of 13 feet below the
existing ground surface. In addition, very wet conditions were encountered west and north
of the existing cabana and pool. A french drain is recommended in this area to remove
water and discharge it to the creek north of the existing improvements. Groundwater and
seepage-related problems are not anticipated if surface drainage is directed into properly
designed drainage structures and away from buildings foundations and other moisture-
sensitive developments.
6.1.5 With the exception of possible sfrong seismic shaking, no significant geologic hazards
were observed or are known to exist on the site or other locations that could adversely
affect the proposed project. A landslide in the southeast comer of the property was
reportedly mitigated during previous grading at the site.
6.1.6 No project grading plans were available for our review. Excavations are expected to be on
the order of 3 feet within the footprint of the proposed structures, with only minor grade
changes outside improvement areas.
6.1.7 The proposed caretaker residence, bathrooms, and bridges can be supported on
conventional continuous and isolated spread footings founded in properly compacted fill or
formational materials. Site retaining walls, flatwork, and other settlement-sensitive
structures can be founded on properly compacted fill. Recommendations are presented in
subsequent sections of this report.
Project No. 06484-22-01 ~- ' April 20,2000
6.2 Excavation and Soil Characteristics
6.2.1 The majority of the soils in the upper 5 feet encountered in the field-investigation are
considered to have a "high" expansion potential (Expansion Index [EI] of 90 to 130) as
defined by the Uniform Building Code (UBC) Table No. 18-I-B.
6.2.2 All the in situ soils can be excavated with moderate to heavy effort by conventional heavy-
duty equipment. However, hard Lusardi Formation strata and cemented zones in the
Delmar Formation may be encountered. The contractor should be aware that excavations in
these materials could be difficult.
6.2.3 It is the responsibility of the contractor to ensure that all excavations and trenches are
properly shored and maintained in accordance with applicable OSHA rules and regulations
in order to maintain safety and maintain the stability of adjacent existing improvements.
6.3 Seismic Design Criteria
6.3.1 The following table summarizes site design criteria obtained from the 1997 Uniform
Building Code (UBC). The values listed in Table 6.3 are for the Rose Canyon and
Elsinore-Julian Fault, which are identified as a Type B and Type A faults, respectively. The
Rose Canyon Fault is located approximately 8 miles southwest and the Elsinore-Julian
Fault is about 22 miles east of the site.
TABLE 6.3
SITE DESIGN CRITERIA
Parameter Value UBC Reference
Seismic Zone Factor 0.40 Table 16-1
Soil Profile Sc Table 16-J
Seismic Coefficient, Ca 0.40 Table 16-Q
Seismic Coefficient, Cv 0.56 Table 16-R
Near-Source Factor, Na 1.0 Table 16-S
Near-Source Factor, Nv 1.0 Table 16-T
Seismic Source A/B Table 16-U
Project No. 06484-22-01 April 20, 2000
6.4 Grading
6.4.1 Grading should be performed in accordance with the Recommended Grading Specifications
in Appendix C. Where the recommendations of this report conflict with Appendix C, the
recommendations of this section take precedence.
6.4.2 Earthwork should be observed, and compacted fill tested by representatives of Geocon
Incorporated.
6.4.3 A preconstruction conference should be held at the site prior to the beginning of grading
operations with the owner, confractor, civil engineer and soil engineer in attendance.
Special soil handling requirements can be discussed at that time.
6.4.4 Grading of the site should commence with the removal of all existing vegetation and
existing improvements from the areas to be graded. Deleterious debris such as wood,
asphalt and concrete should be exported from the site and should not be mixed with the fill
soils. All existing underground improvements within the proposed construction areas
should be removed and the resulting depressions properly backfilled in accordance with the
procedures described herein.
6.4.5 Existing undocumented fill, topsoil, alluvium and colluvium within areas of the new
caretaker residence, bridge footings and restrooms should be removed to a depth of 3 feet
below the bottom of footings elevations or to formational materials, whichever is
shallower. Based on the final location of the structures and geometiy of the foundation
system, we expect removals to be on the order of 1 to 5 feet. This area of recompaction
should extend 5 feet beyond perimeter footing lines. In the proposed parking area,
undocumented fill, topsoil and colluvium should be removed to expose formational
materials. The bottom of the excavations should be scarified to a depth of 12 inches,
moisture conditioned, and compacted to at least 90 percent relative compaction at about
one to three percent above optimum moisture content, as determined by ASTM Test
Method D 1557-96.
6.4.6 If a cut-fill transition will occur beneath a building such that some footings are supported in
compacted fill and other footings on formational materials, the formational materials
should be removed and recompacted to provide a minimum of 2 feet of compacted fill
beneath all the footings of an individual building.
6.4.7 The existing pool has experienced gross disfress. Samples of the on-site soils indicate that
highly expansive, saturated clays in that part of the valley are the principal cause of failure.
Project No. 06484-22-01 -9- April 20,2000
A french drain should be installed in the area of the existing pool and cabaiia early enough
in the construction sequence to prevent neW fills in this area from becoming saturated
again.
6.4.8 Excavated soils generated from cut operations can be placed and compacted in layers to the
design finish grade elevations. All fill and backfill soils should be placed in horizontal
loose layers approximately 8 inches thick, moisture conditioned to a water content above
optimum moisture content, and compacted to at least 90 percent relative compaction as
determined by ASTM Test Method D 1557-96. The upper 12 inches of fill beneath
pavement should be moisture conditioned and compacted to 95 percent relative
compaction.
6.4.9 Import fill soil should consist of granular materials with a "low" expansion potential (EI
less than 50) that are free of deleterious material or stones larger than 3 inches and should
be compacted as recommended above. Geocon Incorporated should be notified of the
import soil source "and should perform laboratory testing of import soil prior to its arrival at
the site to determine its suitability as fill material.
6.4.10 Temporary slopes may be excavated no steeper than 1:1 (horizontal to vertical) without
shoring, provided the top of the excavation is a minimum of 15 feet from the edge of
existing buildings and other improvements. Excavations steeper than 1:1 or closer than 15
feet from an existing improvement, should be shored in accordance with applicable OSHA
codes and regulations.
6.4.11 Permanent cut or fill slopes should be no steeper than 2:1. Slopes, if any, will be composed
of granular soils that are susceptible to surface erosion. Consideration should be given to
the use of jute mesh of other surface treatment to minimize fransport by runoff until
adequate vegetation can take root.
6.5 Foundations
6.5.1 The caretaker residence, foot bridges, and bathroom structure adjacent to the cabaiia can be
supported on conventional continuous or isolated spread footings founded in properly
compacted fill or formational materials. The following foundation recommendations are for
single-story structures and are based upon the assumption that the soil conditions within 4
feet of finish pad subgrade consist of "high" expansive soil (Expansion Index between 90
and 130).
Project No. 06484-22-01 - 10 - April 20, 2000
6.5.2 Continuous strip footings should be at least 12 inches wide and should extend at least 24
inches below lowest adjacent pad grade. Foundations may be designed for an allowable soil
bearing pressure of 1,500 pounds per square foot (psf) in properly compacted fill (dead
plus live load). These soil bearing pressures may be in9reased by 200 psf and 350 psf for
each additional foot of foundation width and depth, respectively, up to a maximum
allowable soil pressure of 2,500 psf in compacted fill.
6.5.3 Isolated spread footings that are a minimum of 2 feet square and founded 24 inches below
lowest adjacent pad grade in properly compacted fill soils may be designed for the
allowable soil bearing pressures above. A footing dimension detail is presented in Figure 3.
6.5.4 Steel reinforcement for continuous footings should consist of at least four No. 5 steel
reinforcing bars placed horizontally in the footings, two near the top and two near the
bottom. Steel reinforcement for the spread footings should be designed by the project
structural engineer.
6.5.5 The minimum reinforcement recommended above is based on soil characteristics only
(Expansion Index of 130 or less) and is not intended to replace reinforcement required for
structural considerations.
6.5.6 Settlement of the buildings founded on properly compacted fill is expected to be about
'/a inch. Differential settlement is expected to be about inch.
6.5.7 Foundation excavations should be observed by a representative of Geocon prior to the
placement of reinforcing steel and concrete to verify that the exposed soil conditions are
consistent with those anticipated. If unanticipated soil conditions are encountered,
foundation modifications may be required.
6.5.8 Footings located within 7 feet of the top of slopes are not recommended. However, footings
that must be located within this zone should be extended in depth such that the outer
bottom edge of the footing is at least 7 feet horizontally inside the face of the slope.
6.6 Concrete Slabs-on-Grade
6.6.1 Concrete slabs-on-grade should be at least 5 inches thick and be reinforced with No. 3 steel
reinforcing bars at 18 inches on center in both horizontal directions. Slabs-on-grade should
be underlain by 4 inches of clean sand. Where moisture sensitive floor covenngs are
planned, the slabs should be underlain by a visqueen moisture barrier placed at the
Project No. 06484-22-01 -11 - April 20,2000
midpoint of the sand blanket. Where heavy concentrated floor loads or heavy equipment
loads are anticipated, the slabs should be designed as portland cement concrete pavements.
6.6.2 The concrete slab-on-grade recommendations are based on soil support characteristics
only. The project structural engineer should evaluate the structural requirements of the
concrete slabs for supporting equipment and storage loads.
6.6.3 All exterior concrete flatwork not subject to vehicular traffic should be constructed in
accordance with the following recommendations. Slab panels in excess of 8 feet square
should be reinforced with 6x6-W2.9AV2.9 (6x6-6/6) welded wire mesh to reduce the
potential for cracking. In addition, all concrete flatwork should be provided with crack
control joints to reduce or control shrinkage cracking. Crack control spacing should be
determined by the project structural 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. Subgrade soils for exterior slabs not subjected to
vehicle loads should be compacted in accordance with criteria presented in the grading
section prior to concrete placement. Subgrade soils should be properly compacted and the
moisture content of surficial soils should be verified prior to placing concrete.
6.6.4 The recommendations presented herein are intended to reduce the potential for cracking of
slabs and foundations as a result of differential movement. However, even with the
incorporation of the recommendations presented herein, foundations and slabs-on-grade
will still exhibit some cracking. The occurrence of concrete shrinkage cracks are
independent of the soil supporting characteristics. Their occurrence may be reduced or
controlled by limiting the slump of the concrete by the use of crack control joints, and by
proper concrete placement and curing. Crack control joints should be spaced at intervals no
greater than 12 feet. Literature provided by the Portland Concrete Association (PCA) and
American Concrete Institute (ACI) present recommendations for proper concrete mix,
construction, and curing practices, and should be incorporated into project construction.
6.7 Lateral Loading
6.7.1 To resist lateral loads, a passive pressure exerted by an equivalent fluid weight of 300
poimds per cubic foot (pcf) should be used for design of footings or shear keys poured neat
against properly compacted granular fill soils. The upper ,12 inches of material in areas not
protected by floor slabs or pavement should not be included in design for passive
resistance.
Project No. 06484-22-01 - 12 - April20, 2000
I
I 6.7.2 If friction is to be used to resist lateral loads, an allowable coefficient of friction between
soil and concrete of 0.35 should be used for design.
6.8 Retaining Walls
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
35 pcf Where the backfill will be inclined at 2:1 (horizontal:vertical), an active soil
pressure of 54 pcf is recommended. Expansive soils should not be used as backfill material
behind retaining walls. All soil placed for retaining wall backfill should have an Expansion
Index less than 50. The-zone of low-expansive backfill should extend at an inclination of
1:1 up from the top of the wall footing behind the wall.
6.8.2 Unresfrained walls are those that are allowed to rotate more than 0.00IH (where H equals
the height of the retaining wall portion of the wall) at the top of the wall. Where walls are
restrained from movement at the top, an additional uniform pressure of 8H psf should be
added to the above active soil pressure, where H is the height of the wall.
6.8.3 Retaining walls should be provided with a drainage system adequate to prevent the buildup
of hydrostatic forces and should be waterproofed as required by the project architect. The
use of drainage openings through the base of the wall (weep holes) is not recommended
where the seepage could be a nuisance or otherwise adversely effect the property adjacent
to the base of the wall. A retaining wall drainage detail is presented on Figure 4. The above
recommendations assume a properly compacted granular (EI less than 50) free-draining
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.
6.9 Pavements
6.9.1 Based on our review of the site plan, it is understood that pavement recommendations are
required for the parking lot in the southeast portion of the site. We understand that
decomposed granite (DG) will be used as the final surface. An R-value test performed on
near-surface soils obtained in the parking lot area indicated an R-value of less than 5.
Although there are no design guidelines for DG pavements, past experience was used to
provide the following pavement sections.
6.9.2 The City of Carlsbad typically requires lime treatment for subgrade soils with an R-value
of less than 12. The upper 8 inches in auto parking areas and the upper 12 inches in
Project No. 06484-22-01 - 13 - April 20, 2000
driveway areas should be treated with 6 percent lime by dry weight. Lime-treated pavement
subgrade should be properly raoistlire conditioned and compacted to a minimum relative
compaction of 95 percent as determined by ASTM D 1557-91. Finished surfaces should be
constructed by covering the lime-treated subgrade with 5 inches of decomposed granite
(DG) in auto parking areas and 6 inches of DG in driveway areas. The DG should be
compacted to 95 percent relative compaction at optimum moisture content.
6.10 Site Drainage and Moisture Protection
6.10.1 Adequate drainage is critical to reduce the potential for differential soil movement, erosion
and subsurface seepage.-Under no circumstances should water be allowed to pond adjacent
to footings. The site should be graded and maintained such that surface drainage is directed
away from structures and the top of slopes into swales or other controlled drainage devices.
Roof and pavement drainage should be directed into conduits which carry runoff away
from the proposed structure.
6.10.2 A french drain should be installed in the area of the existing pool and cabaiia area to carry
groundwater away from this area. Proper surface drainage also should be provided.
6.10.3 Landscaping planters adjacent to paved areas are not recommended due to the potential for
surface or irrigation water to infilfrate the pavement subgrade and base course. We
recommend that subdrains to collect excess irrigation water and transmit it to drainage
structures, or impervious above-grade planter boxes be used. In addition, where
landscaping is planned adjacent to the pavement, we recommended construction of a cutoff
wall along the edge of the pavement that extends at least 6 inches below the bottom of the
base material.
6.11 Foundation and Grading Plan Review
6.11.1 Geocon Incorporated should review the grading plans and foundation plans for the project
prior to final design submittal to determine if additional analysis or recommendations are
required.
Project No. 06484-22-01 - 14- April 20,2000
I
LIMITATIONS AND UNIFORMITY OF CONDITIONS
1. The recommendations of this report penain 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 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 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 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. 06484-22-01 Apnl 20, 2000
I
I "••"mm
SOURCE: 2000 THOMAS BROTHERS MAP
SAN DIEGO COUNTY, CALIFORNIA
REPRODUCED WITH PERMISSION GRANTED BY THOMAS. BROTHERS MAPS.
THIS MAP IS COPYRIGHTED BY THOMAS BROS. MAPS. IT IS UNLAWFUL TO COPY
OR REPRODUCE ALL OR ANY PART THEREOF. WHETHER FOR PERSONAL USE OR
RESALE. WITHOUT PERMISSION
4
M
NO SCALE
GEOCON
INCORPORATED . O
GEOTECHNICAL CONSULTANTS
6960 FLANDERS DRIVE - SAN DIEGO, CALIFORNIA 92121 • 2974
PHONE 858 558-6900 - FAX 858 558-6159
JV/AML DSK/DOOOD
VICINITY MAP
LEO CARILLO RANCH
CARLSBAD, CALIFORNIA
DATE 04-20-2000 ..PROJECT NO. 06484 - 22 - 01 FIG. 1
WALL FOOTING
SAND PAD GRADE
VISQUEEN
COLUMN FOOTING
CONCRETE SLAB
.0. .0.
n • ^ • O • • O • • O •
• • - . o . . . °- . o • . . ° . o . . ° SAND .
VISQUEEN •
.0.
.O. . .0.
• - • o .. • • o .. • • • a - • • • c .•
•^•\s o." • .• • .0.- • '• - " •
.0. ' .'.<b. '.'.0.
0.-
.O
.' .'.<). ..O. . • .'. O. ':" '.'.<>
\yAw/
FOOTING WIDTH
* SEE REPORT FOR FOUNDATION WIDTH AND DEPTH RECOMMENDATION
NO SCALE
WALL / COLUMN FOOTING DIMENSION DETAIL
GEOCON
INCORPORATED
GEOTECHNICAL CONSULTANTS
6960 FLANDERS DRIVE - SAN DIEGO, CALIFORNIA 92121-2974
PHONE 619 558-6900 - FAX 619 558-6159
JV/AML DSK/GTYPD
LEO CARILLO RANCH
CARLSBAD, CALIFORNIA
DATE 04-20-2000 PROJECT NO. 06484 - 22 - 01 FIG. 3
COlfOOT VIII/IXVII / RSS
12" MIN. GROUND
SURFACE
RETAINING
WALL
3/4" CRUSHED
GRAVEL
MIRAFI 140
FILTER FABRC
OR EQUIVALENT
4" DIA. PERFORATED
ABS OR ADS PIPE
NOTES:
1 PREFABRICATED DRAINAGE PANELS, SUCH AS MIRADRAIN 7000 OR EQUIVALENT,
MAYBE USED IN LIEU OF PLJ^CING GRAVEL TO HEIGHT OF 2/3 THE TOTAL WALL HEIGHT
2 DRAIN SHOULD BE UNIFORMLY SLOPED AND MUST LEAD TO A POSITIVE GRAVITY OUTLET
3 TEMPORARY EXCAVATION SLOPES SHOULD BE CONSTRUCTED AND/OR SHORED IN
ACCORDANCE WITH CAL-OSHA REGULATIONS
NO SCALE
RETAINING WALL DRAINAGE DETAIL
GEOCON
INCORPORATED O
GEOTECHNICAL CONSULTANTS
6960 FLANDERS DRIVE • SAN DIEGO, CALIFORNIA 92121 - 2974
PHONE 858 558-6900 - FAX 858 558-6159
JV/AML DSK/GTYPD
LEO CORILLO RANCH
CARLSBAD, CALIFORNIA
DATE 04-20-20005 PROJECT NO. 06484 - 22 - 01 FIG. 4
RETWALL/VII-IXVRSS
A
I
APPENDIX A
FIELD INVESTIGATION
The field investigation was perforrhed on February 28, 2000, and consisted of the excavation of six
small-diameter power auger borings and three hand auger borings at the approximate locations shown
on Figure 2. The small-diameter borings were drilled to depths ranging from IV2 feet to 16 feet below
existing grade using an Ingersoll-Rand A-300 truck-mounted drill rig equipped with 8-inch-diameter,
hollow-stem auger.
Relatively undisturbed samples were obtained with the drill rig by driving a 3-inch O. D., split-tube
sampler 12 inches into the undisturbed soil mass with blows from a 140-pound hammer falling 30
inches. The split-tube sampler was equipped with 1-inch-high by 2V8-inch-diameter brass sampler
rings to facilitate sample removal and testing. Disturbed bulk samples were obtained from drill
cuttings. Hand auger borings were advanced to depths of 4 to 5 feet in areas not accessible to the drill
rig. Disturbed bulk samples were taken continuously from near the surface to the bottoms of
the holes.
The soil and rock conditions encountered in the borings were visually examined, classified, and
logged in general conformance with the American Society for Testing and Materials (ASTM)
Practice for Description and Identification of Soils (Visual-Manual Procedure D2844). The logs of
the exploratory borings are presented on Figures A-1 through A-9. The logs depict the various soil
and rock types encountered and indicate the depths at which samples were obtained.
Project No. 06484-22-01 April 20, 2000
PROJECT NO. 06484-22-01
DEPTH
IN
FEET
SAMPLE
NO.
SOIL
CLASS
(USCS)
BORING B 1
ELEV. (MSL.) 305
EQUIPMENT
_DATE COMPLETED
m A-3000 8" HSFN
3/28/00
jLU'
Pi
gL
a
LU
-o
O
- 0 MATERIAL DESCRIPTION
- 2 -
- 4 -
- 6 -
Bl-1
Bl-2
Bl-3
Bl-4
10 -•Bi-5-
CH
TOPSOIL
Soft, moist, medium brown CLAY with sand
-40-444-^ -l&M-
LUSARDI FORMATION
Very dense, moist to damp, reddish-brown,
DECOMPOSED CONGLOMERATE 90/9"
-Grades to mottled light gray and reddish-brown,
highly weathered
BORING TERMINATED AT 10.5 FEET
111.3 17.4
igure A-1, Log of Boring B 1 LEOCR
SAMPLE SYMBOLS • ... SAMPLING UNSUCCESSFUL c. .. STANDARD PENETRATION TEST • . .. DRIVE SAMPLE (UNDISTURBED)
^ ... DISTURBED OR BAG SAMPLE B. .. CHUNK SAMPLE f . .. WATER TABLE OR SEEPAGE
I
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.
PROJECT NO. 06484-22-01
DEPTH
IN
FEET
BORING B 2
ELEV. (MSL.) 284
EQUIPMENT
DATE COMPLETED 3/28/00
IR A-3000 8" HSFN
jUJ'
UL
OC
iL
UJ U
Q
UJ5 a:
=3.-
CO
- 0
- 2
MATERIAL DESCRIPTION
4 -
6 -
FILL
Firm, moist, olive-brown, Sandy CLAY with scattered
gravel
COLLUVIUM
Medium stiff to stiff, moist to damp, dark brown,
Sandy CLAY
- 26
LUSARDI FORMATION
Very dense, damp, yellowish-brown, highly weathered
CONGLOMERATE
114.4
50/6" 134.9
13.8
4.9
BORING TERMINATED AT 7.5 FEET
AUGER REFUSAL
Figure A-2, Log of Boring B 2 LEOCR
SAMPLE SYMBOLS D... SAMPLING UNSUCCESSFUL c. .. STANDARD PENETRATION.TEST • . .. DRIVE SAMPLE (UNDISTURBED)
^ ... DISTURBED OR BAG SAMPLE B. .. CHUNK SAMPLE f . .. 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.
I
I
PROJECT NO. 06484-22-01
DEPTH
IN
FEET
SAMPLE
MO.
BORING B 3
ELEV. (MSL.) 296
EQUIPMENT
DATE COMPLETED
IR A-3000 8" HSFN
3/28/00
H I-H'
Ul
Q
.\*
LU
- 0 MATERIAL DESCRIPTION
- 2 -
4 -
FILL
Medium stiff to stiff, moist, mottled pale brown and
gray, Sandy CLAY
COLLUVIUM
Stiff, moist, medium brown, Sandy CLAY - 27 120.0 15.5
- 6
- 10 -B3-6
DELMAR FORMATION
Very stiff, damp, mottled pale gray and brownish-red
CLAYSTONE
-Litde brownish-red mottling
55 115.9 14.7
50/6" 116.0 13.9
BORING TERMINATED AT 11 FEET
1
Figure A-3, Log of Boring B 3 LEOCR
SAMPLE SYMBOLS ° '"' '''''''' UNSUCCESSFUL
S ... DISTURBED OR BAG SAMPLE
c.
B..
. STANDARD PENETRATION TEST B... DRIVE SAMPLE (UNDISTURBED)
. CHUNK SAMPLE X ... 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. 06484-22-01
DEPTH
IN
FEET
SAMPLE
NO.
>-CD O _l O X
1-
H
SOIL
CLASS
(USCS)
BORING B 4
ELEV. (MSL.) 286
EQUIPMENT
DATE COMPLETED
m A-3000 8" HSFN
3/28/00
cn,
a
Q
cn LU
•o
u MATERIAL DESCRIPTION
2 -
B4-1
CH TOPSOIL
Firm, moist, grayish-brown, CLAY with sand
DELMAR FORMATION
Very stiff, damp, brownish-red CLAYSTONE 50/4.5" 121.2 13.1
BORING TERMINATED AT 3.5 FEET
Figure A-4, Log of Boring B 4 LEOCR
SAMPLE SYMBOLS • SAMPLING UNSUCCESSFUL B. .. STANDARD PENETRATION TEST • .. . DRIVE SAMPLE (UNDISTURBED) SAMPLE SYMBOLS
^ ... DISTURBED OR BAG SAMPLE B. . CHUNK SAMPLE . WATER TABLE OR SEEPAGE
I
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.
PROJECT NO. 06484-22-01
DEPTH
IN
FEET
SAMPLE
NO.
> C3 O _J o X t-H
SOIL
CLASS
(USCS)
BORING B 5
ELEV. (MSL.) 255
EQUIPMENT
DATE COMPLETED
IR A-3000 8" HSFN
3/28/00
^cn°
>
UJ
a
cn LU
MATERIAL DESCRIPTION
- 2
4 -
- 6
8 -
10 -
ALLUVIUM
Firm, moist, grayish-brown CLAY with sand
-Increasing sand with fine gravel, fragments of
weathered claystone
CH
- 15
15
108.3
108.6
B5-4 DELMAR FORMATION
Firm, very moist, mottled pale gray and
brownish-yellow, highly weathered CLAYSTONE
BORING TERMINATED AT 11 FEET
11 100.8
19.2
20.2
25.8
Figure A-5, Log of Boring B 5 LEOCR
SAMPLE SYMBOLS • ... SAMPLING UNSUCCESSFUL E. .. STANDARD PENETRATION TEST 1. .. DRIVE SAMPLE (UNDISTURBED) SAMPLE SYMBOLS
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. 06484-22-01
DEPTH
IN
FEET
SAMPLE
NO.
SOIL
CLASS
(USCS)
BORING B 6
ELEV. (MSL.) 264
EQUIPMENT
DATE COMPLETED 3/28/00
IR A-3000 8" HSFN
H
CH
;LU'
1—1-^
gL
LU U
Q
- 0 MATERIAL DESCRIPTION
- 2 -
4 -
- 6 -
8 -
- 10 -
12
- 14
B6-3 CH
ALLUVIUM
Firm, moist, medium grayish-brown CLAY, with
sand
-Stiff, moist, brownish-gray, Sandy CLAY with fine
gravel
-Grades to yellowish-brown
- 22
18
B6-4
B6-5
- 16
DELMAR FORMATION
Stiff, wet, mottled pale gray and brownish-red, highly
weathered CLAYSTONE
114.0
106.1
20 106.4
18 103.3
BORING TERMINATED AT 16 FEET
Figure A-6, Log of Boring B 6 LEOCR
SAMPLE SYMBOLS • SAMPLING UNSUCCESSFUL c. .. STANDARD PENETRATION TEST • . .. DRIVE SAMPLE (UNDISTURBED) SAMPLE SYMBOLS
S ... DISTURBED OR BAG SAMPLE B. .. CHUNK SAMPLE f . .. 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. 06484-22-01
DEPTH
IN
FEET
SAMPLE
NO.
BORING HA 1
ELEV. (MSL.) 243
EQUIPMENT
DATE COMPLETED
m A-3000 8" HSFN
3/28/00 cniy
cnR Ul'zi
H'
cn, LU u
a
LU
u
MATERIAL DESCRIPTION
HA 1-1
9 -
HAl-2
FILL
Soft to firm, wet, dark gray, Sandy CLAY, very
common roots
ALLUVIUM
Firm wet, dark gray, Sandy CLAY with fragments of
weathered claystone; common roots
BORING TERMINATED AT 5 FEET
Figure A-7, Log of Boring HA 1 LEOCR
SAMPLE SYMBOLS • ... SAMPLING UNSUCCESSFUL c... STANDARD PENETRATION TEST • . .. DRIVE SAMPLE (UNDISTURBED) SAMPLE SYMBOLS
S ... DISTURBED OR BAG SAMPLE B... CHUNK SAMPLE T . .. WATER TABLE OR SEEPAGE
I
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.
PROJECT NO. 06484-22-01
DEPTH
IN
FEET
SAMPLE
NO.
> CD O
I-H
SOIL
CLASS
(USCS)
BORING HA 2
ELEV. (MSL.) 241
EQUIPMENT
DATE COMPLETED 3/28/00
IR A-3000 8" HSFN
LU
LU'^
cH§
cng LUsi
^U LUf
a
LU*5
OC
3.
UJ
•o u
- 0
HA2-1
2 -
MATERIAL DESCRIPTION
CH
ALLUVIUM
Soft to firm, wet, mottled medium gray and brown,
Sandy CLAY
BORING TERMINATED AT 4 FEET
I
I
I
igure A-8, Log of Boring HA 2 LEOCR
SAMPLE SYMBOLS • SAMPLING UNSUCCESSFUL C
^ ... DISTURBED OR BAG SAMPLE B
STANDARD PENETRATION TEST DRIVE SAMPLE (UNDISTURBED)
CHUNK SAMPLE T. ... 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. 06484-22-01
SAMPLE
NO.
SOIL
CLASS
(USCS)
BORING HA 3
ELEV. (MSL.) 253
EQUIPMENT
DATE COMPLETED
m A-3000 8" HSFN
3/28/00
cn' UJ:
§L
LU U
a u
- 0
- 2
MATERIAL DESCRIPTION
HA3-1
ALLUVIUM
Soft to firm, wet, motded medium gray and brown,
Sandy CLAY
DELMAR FORMATION
Firm, wet, mottled light gray and brownish-red,
highly weadiered CLAYSTONE
BORING TERMINATED AT 4 FEET
figure A-9, Log of Boring HA 3 LEOCR
SAMPLE SYMBOLS • ... SAMPLING UNSUCCESSFUL c. . STANDARD PENETRATION TEST • .. . DRIVE SAMPLE (UNDISTURBED) SAMPLE SYMBOLS
@ ... DISTURBED OR BAG SAMPLE B.. . CHUNK SAMPLE . WATER TABLE OR SEEPAGE
t
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.
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. Selected soil samples were
tested for their in-place dry density and moisture content, maximum dry unit weight, optimimi
moisture content, expansion potential, consolidation, pavement support, and shear strength
characteristics.
The results of our laboratory tests are presented on Tables B-I through B-IV and Figure B-1. The in-
place dry density and moisture content results are indicated on the exploratory boring logs.
TABLE B-I
SUMMARY OF IN-PLACE DENSITY AND DIRECT SHEAR TEST RESULTS
Sample
No.
Dry
Density
(pcf)
Moisture
Content
(%)
Unit
Cohesion
(psf)
Angle of Shear
Resistance
(degrees)
B5-2 . 108.3 19.2 250 24
TABLE B-ll
SUMMARY OF LABORATORY EXPANSION INDEX TEST RESULTS
Sample No.
Moisture Content Dry Density
(pcf) Expansion Index Sample No.
Before Test (%) After Test (%)
Dry Density
(pcf) Expansion Index
B3-3 9.2 27.1 113.4 101
HA-2 8.8 28.4 112.4 113
TABLE B-lll
SUMMARY OF LABORATORY MAXIMUM DRY DENSITY
AND OPTIMUM MOISTURE CONTENT TEST RESULTS
ASTM D-1557-91
Sample
No. Description Maximum Dry
Density(pcf)
Optimum Moisture
Content (% dry wt.)
B2-2 Dark brown Sandy CLAY 122.0 12.7
Project No. 06484-22-01 -B-April 20, 2000
TABLE B-IV
SUMMARY OF LABORATORY RESISTANCE VALUE TEST RESULTS
Sample No. Description Resistance Value
Bl-1 Brown CLAY with Sand <5
Project No. 06484-22-01 • B-2. April 20, 2000
PROJECT NO. 06484-22-01
o H I-<E Q H _I O cn z o u
Ul
o OC LU Q.
SAMPLE NO. B3-2
-2
10
12 0.1 10 100
APPLIED PRESSURE (ksf)
Initial Dry Density (pcf) 120.0
Initial Water Content (%) 15.5
Initial Samration (%) 100-1-
Sample Saturated at (ksf) 0.5
CONSOLIDATION CURVE
LEO CARILLO RANCH
CARLSBAD, CALIFORNIA
LEOCR Figure B-I
APPENDIX C
RECOMMENDED GRADING SPECIFICATIONS
FOR
LEA CARRILLO RANCH
PHASE 2
CARLSBAD, CALIFORNIA
PROJECT NO. 06484-22-01
RECOMMENDED GRADING SPECIFICATIONS
1. 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 of the earthwork and
grading specifications and shall supersede the provisions contained hereinafter in the case
of conflict.
1.2. Prior to the commencement of grading, a geotechnical consultant (Consultant) shall be
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, 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 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
performed.
2.2. Contractor shall refer to the Contractor performing the site grading work.
2.3. Civil Engineer or Engineer of Worlt 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. 8/98
2.4. Consultant shall refer to the soil engineering and engineering geology consulting firm
retained to provide geotechnical services for the project.
2.5. Soil Engineer shall refer to a 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 California licensed Engineering Geologist retained
by the Owner to provide geologic observations and recommendations during the site
grading.
2.7. Geotechnical Report shall refer to a soil report (including all addenda) which may include
a geologic reconnaissance or 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 die 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 maxunum 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 defmed as material greater than 12
inches.
3.1.3. Rock fills are defmed as fills containing no rocks or hard lumps larger than 3 feet
in maximum dimension and containing little or no fines. Fines are defined as
material smaller than 3/4 inch in maximum dimension. The quantity of fines shall
be less than approximately 20 percent of the rock fill quantity.
GI rev. 8/98
3.2. Material of a perishable, spongy, or otherwise unsuitable 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 die 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 (horizontahvertical) and a soil
layer no thicker than 12 inches is ti^ck-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 identified in the
Geotechnical Report may be encountered by the Contractor. The Consultant shall be
notified immediately to evaluate the significance of the unanticipated condition
4. CLEARING AND PREPARING AREAS TO BE FILLED
4.1. Areas to be excavated and filled shall be cleared and grubbed. Clearing shall consist of
complete removal above the ground surface of trees, stumps, brush, vegetation, man-made
structures and similar debris. Grubbing shall consist of removal of stumps, roots, buried
logs and other unsuitable material and shall be performed in areas to be graded. Roots and
other projections exceeding 1-1/2 inches in diameter shall be removed to a depth of 3 feet
below the surface of the ground. Borrow areas shall be grubbed to the extent necessary to
provide suitable fill materials.
GI rev. 8/98
I
I
I
I
I
I
I
I
1
I
I
I
I
I
I
I
I
I
I
4.2.
4.3.
Any asphalt pavement material removed during clearing operations should be properly
disposed at an approved off-site facility. Concrete fragments which are free of reinforcing
steel may be placed in fills, provided they are placed in accordance with Section 6.2 or 6.3
of this document.
After clearing and grubbing of organic matter or other unsuitable material, loose or porous
soils shall be removed to die 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.
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
4.4.
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
No Scale
DETAIL NOTES: (1) Key width "B" should be a minimum of 10 feet wide, or sufficiently wide to
permit complete coverage with the compaction equipment used. The base of the
key should be graded horizontal, or inclined slightly into the natural slope.
(2) The outside of the bottom key should be below the topsoil or unsuitable surficial
material and at least 2 feet into dense formational material. Where hard rock is
exposed in the bottom of the key, the depth and configuration of the key may be
modified as approved by the Consultant.
GI rev. 8/98
4.5. After areas to receive fill have been cleared, plowed or scarified, the surface should be
disced or biaded by the Contractor until it is uniform and free from large clods. The area
should then be moisture conditioned to achieve the proper moisture content, and compacted
as recommended in Section 6.0 of these specifications.
5. COMPACTION EQUIPMENT
5.1. Compaction of soil or soil-rock fill shall be accomplished by sheepsfoot or segmented-steel
wheeled rollers, vibratory rollers, multiple-wheel pneumatic-tired rollers, or other types of
acceptable compaction equipment. Equipment shall be of such a design that it will be
capable of compacting the soil or soil-rock fill to the specified relative compaction at the
specified 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 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 D1557-91.
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 cranpaction, the soil fill shall be aerated by
the Conti^ctor by blading/mixing, or other satisfactory metiiods until the moisture
content is within the range specified.
GI rev. 8/98
I
I
I
6.1.5. After each layer has been placed, mi.xed, 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 the maximum laboratory dry density as
determined in accordance with ASTM 01557-91. 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 following paragraph.
6.1.8. As an alternative to over-building of slopes, slope faces may be back-rolled with a
heavy-duty loaded sheepsfoot or vibratory roller at maximum 4-foot fill height
intervals. Upon completion, slopes should then be frack-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 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. 8/98
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 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" metiiod in lieu of die 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
geometiy. 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 Contractor in accordance with
the following recommendations:
6.3.1. The base of the rock fill shall be placed on a sloping surface (minimum slope of 2
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 permanentiy connected to controlled drainage facilities to
confrol post-construction infiltration of water.
6.3.2. Rock fills 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 dozer to facilitate jeariwg of the
rock. The rock fill shall be watered heavily during placement. Watering shall
consist of water tiTJcks fraversing in front of die current rock lift face and spraying
water continuously during rock placement. Compaction equipment witii
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
GI rev. 8/98
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 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 196-64, 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 oirock 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 arei 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 rocjtfill placed.
6.3.5. Test pits shall be excavated by die Contractor so that the Consultant can state that,
in his opinion, sufficient water is present and that voids between large rocks are
properly filled with smaller rock material. In-place density testing will not be
required in the rock fills.
6.3.6. To reduce the potential for "piping" of fines into the rock fill from.overlying soil
fill material, a 2-foot layer of graded filter material shall be placed above the
uppermost lift of rock fill. The need to place graded filter material below the rock
should be determined by the Consultant prior to commencing grading. The
gradation of the graded filter material will be determined at the time the rock fill is
being excavated. Materials typical of the rock fill should be submitted to the
Consultant in a timely manner, to allow design of the graded filter prior to the
commencement of rock fill placement.
GI rev. 8/98
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 of the 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 tiian the
maximum deflection of the properly compacted JO// 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 die 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. 8/98
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 Soli-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 D2922-81, 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 10-Pound Hammer
and J 8-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 Dl 196-64 (Reapproved 1977) Standard
Methodfor 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 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 die site. The
Confractor shall take remedial measures to prevent erosion of freshly graded areas until
such tune as permanent drainage and erosion confrol 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.
GI rev. 8/98
I
I
I
I
I
I
I
1
I
I
I
I
I
I
I
I
I
I
I
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 within 0.1 foot vertically of
elevations shown on the grading plan and that all tops and toes of slopes are within 0.5 foot
horizontally of the positions shown on the grading plans. After installation of a section of
subdrain, the project Civil Engineer should survey its location and prepare an as-built plan
of the 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 Califomia licensed Civil Engineer experienced m
geotechnical engineering and by a Califomia Certified Engineering Geologist, indicating
that the geotechnical aspects of the grading were performed in substantial conformance
with the Specifications or approved changes to the Specifications.
GI rev. 8/98
APPENDIX D
REFERENCES
1. Blake, T. F., EQFAULT, A Computer Program for the Deterministic Prediction of Peak
Horizontal Acceleration from Digitized Califomia Faults, Users Manual, 1989a, p. 79
(revised 1993).
2. California Department of Conservation, Division of Mines and Geology: Landslide Hazards
in the Northern Part of the San Diego Metropolitan Area, San Diego County, California;
Open-File Report 95-04, 1995.
3. Califomia Department of Conservation, Division of Mines and Geology: Geologic Maps of
the Northwestern Part of San Diego County, Califomia; Open-File Report 96-02, 1996.
4. San Diego County: 1 "=200' Orthophoto Topographic Map 346-1695, edition of 1975.
5. U.S. Department of Agriculture: 1:20,000 scale vertical aerial photographs AXN-8M-19
and .20, 1953.
6. U.S. Department of Agriculture: Soil Conservation Service: Soil Survey, San Diego Area,
1973.
7. U.S. Geological Survey: I "=2,000'scale Rancho Santa Fe Quadrangle, 1968, photorevised
1983.
8. Unpublished reports, aerial photographs and maps on file with Geocon Incorporated.
Project No. 06484-22-01 April 20,2000