HomeMy WebLinkAboutCT 02-05; VILLAGES OF LA COSTA OAKS SOUTH NEIGHBORHOOD 3.15; FINAL REPORT OF TESTING & OBSERVATION DURING SITE GRADING; 2003-10-08FINAL REPORT
OF TESTING AND OBSERVATION
SERVICES PERFORMED
DURING SITE GRADING
VILLAGES OF LA COSTA -
THE OAKS SOUTH
NEIGHBORHOOD 3.15 - LOT 103
RECREATION CENTER BUILDING PAD
CARLSBAD, CALIFORNIA
PREPARED FOR
REAL ESTATE COLLATERAL
MANAGEMENT COMPANY
C/0 MORROW DEVELOPMENT INCORPORATED
CARLSBAD, CALIFORNIA
OCTOBER 8, 2003
GEOCON 0 N C 0 ft P 0 ft A T ft D
GEOTECHNICAL CONSULTANTS
Project No. 06105-52-06
October 8, 2003
Real Estate Collateral Management Company
C/0 Morrow Development Incorporated
1903 Wright Place, Suite 108
Carlsbad, California 92008
Attention: Mr. Tim O'Grady
Subject: VILLAGES OF LA COSTA - THE OAKS SOUTH
NEIGHBORHOOD 3.15 - LOT 103
RECREATION CENTER BUILDING PAD
CARLSBAD, CALIFORNIA
FINAL REPORT OF TESTING AND OBSERVATION
SERVICES PERFORMED DURING SITE GRADING
Gentlemen:
In accordance with your request and our proposal dated May 3, 2002, we have prepared this final
report of compaction testing and observation services provided during the grading of the subject site.
Our services were performed during the period of December 16, 2002 through September 15, 2003.
The scope of our services summarized in this report included the following:
Observing the grading operation, including the removal and/or processing of topsoil,
colluvium, alluvium, and undocumented fill.
Performing in-situ dry density and moisture tests in fill placed and compacted at the site.
Performing laboratory tests to aid in evaluating maximum dry density and optimum moisture
content of the compacted fill soils. Additionally, laboratory tests were performed on samples
of soil present at finish grade to evaluate expansion characteristics and water-soluble sulfate
content.
Preparing an "As-Graded" Geologic Map.
Preparing this final report of grading.
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6960 Flanders Drive I San Diego, California 92121-2974 • Telephone (858) 558-6900 • Fax (858) 558-6159
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The purpose of this report is to document that the grading for Neighborhood 3.15 - Lot 103 has been
performed in substantial conformance with the recommendations of the project geotechnical report
and that fill materials have been properly placed and compacted.
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It is our understanding that four separate buildings and a swimming pool will be constructed for the
recreation center. The grading operations for the recreation center building pad were performed
concurrently with those for the balance of The Oaks South project.
I GENERAL
The grading contractor for the project was Erreca's Incorporated of Lakeside, California. Grading
plans for the project were prepared by Hunsaker and Associates and are entitled Grading and
I Erosion Control Plans for Villages of La Costa, Oaks South, Neighborhood 3.15, with City of
Carlsbad approval dated May 27, 2003. A digital version of the grading plans was used as the base
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map for our As- Graded Geologic Map (Figure 1, map pocket). The project geotechnical report is
entitled Update Geotechnical Investigation, Villages of La Costa - The Oaks, Carlsbad, California,
dated August 3, 2001 (Project No. 06105-12-04).
I References to elevations and locations herein are based on surveyor's or grade-checker's stakes in the
I field and/or interpolation from the referenced Grading Plans. Geocon Incorporated does not provide
surveying services and, therefore, has no opinion regarding the accuracy of the as-graded elevations
or surface geometry with respect to the approved grading plans, or proper surface drainage.
GRADING
I The Recreation Center - Lot 103 is located within of the Villages of La Costa - The Oaks South
Neighborhood 3.15, just south of the intersection of Circulo Sequoia and Corte Delfinio. Prior to
- - grading, Lot 103 primarily consisted of a northwest-facing ridge near the intersection of two tributary
canyons. The north-south trending tributary canyon located west of Lot 103 ultimately intersected
I Encinitas Creek along the southern boundary of The Oaks South development. Grading for the site
consisted of daylight cuts and fills on the order of 20 and 40 feet, respectively, to achieve the finish
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grade elevations.
Grading began with the removal of brush and vegetation from the area to be graded. The brush was
I then exported. Topsoils, slopewash and alluvial soils were removed to expose formational material.
Within these areas, and prior to placing fill, the exposed (overexcavated) ground surface was
I scarified (where possible), moisture conditioned, and compacted. Areas of remedial grading that
exposed metavolcanic rock were not scarified. Fill materials derived from on-site excavations were
then placed and compacted in layers until the design elevations were attained. In addition, fill was
Project No. 06105-52-06 -2 - October 8, 2003
placed as a result of the undercutting of the cut portion of cut-fill transition lots, and lots where
metavolcanic rock, topsoil or clay was exposed at grade. Roadway and parkway undercuts were also
performed where metavolcanic rock was exposed. Roadway undercuts consisted of undercutting to a
depth of approximately 1 foot below the deepest utility. Parkway undercuts consisted of undercutting
to a depth of approximately 6 feet below finish grade. Lot undercuts consisted of undercutting to a
depth of at least 3 feet below finish grade.
Fill Materials and Placement Procedures
The on-site fill materials generally varied between angular gravels and boulders produced by onsite
blasting of hard metavolcanic rock to clayey, fine sands, sandy to silty clay and sandy to clayey
gravels. Structural fill placed and compacted at the site consisted of material which can be classified
into three zones: (1) Zone A - Material placed within 3 feet from pad grade, 6 feet from parkway
grade, and within roadways to at least 1 foot below the deepest utility consisted of "soil" fill with a
maximum particle dimension of 6-inches. (2) Zone B - Material placed within 10 feet from pad grade
and below Zone A consisted of "soil-rock" fill with a maximum particle dimension of 12 inches. In
addition, material placed on the outer 6 feet of fill slopes and 2 feet below Zone A for fills in
I roadways and parkways consisted of "soil-rock" fill with a maximum particle dimension of 12
inches. (3) Zone C - Material placed below Zone B consisted of "soil-rock" fill and "rock" fill with a
I maximum particle dimension of 4 feet. It should also be noted that larger rocks with a maximum
dimension of approximately 8 feet were buried individually during "rock" fill grading operations.
I Placement procedures for "soil-rock" and "rock" fills consisted of spreading and compacting the
material with a D9 or larger Caterpillar bulldozer with a maximum lift size of 3 feet. Materials ' placed as "soil-rock" and "rock" fills were watered heavily during spreading to place finer grained
material between the rocks. During the placement of each lift, compactive effort was applied to the
fill by wheel-rolling with loaded rock trucks such that the entire lift was compacted.
Soil fills were placed in lifts no thicker than would allow for adequate bonding and compaction. The
1 soil was moisture conditioned as necessary, mixed during placement, then compacted utilizing
conventional heavy-duty compaction equipment.
During the grading operations, compaction procedures were observed and in-place density tests were
performed to evaluate the dry density and moisture content of the "soil" and "soil-rock" fill material.
The in-place density tests were performed in general conformance with ASTM Test Method
D 2922-91, Standard Test Method for Density of Soil and Soil-Aggregate in Place by Nuclear
Methods. Test excavations in "soil-rock" and "rock" fills containing larger rock particles typically
resulted in significant soil disturbance yielding unreliable in-place density test results. When this
occurred, test pits were excavated and observed for the condition of the rock and soil matrix with
Project No. 06105-52-06 - 3 - October 8, 2003
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I respect to "seating" and void content. In-place density testing was not practical at these disturbed
locations. As such, in-place moisture tests were performed on the "soil-rock" and "rock" fill
I materials. These in-place moisture tests have been summarized with a prefix "M" to designate an in-
place moisture content test only.
I The results of the in-place dry density and moisture content tests are summarized in Table I. Grading
for Lot 103 was performed concurrently with the balance of Neighborhood 3.15 and
I Neighborhoods 3.8 through 3.14 of the Villages of La Costa - The Oaks South development. The
results presented in Table I are for Lot 103 only. As such, the test numbers are not in consecutive
I order.
Using methods suggested by AASHTO T224-86, corrections were made to the laboratory maximum
dry density and optimum moisture content on fill soils being tested containing rocks larger than 3/4
inch. The values of maximum dry density and optimum moisture content presented in Table I reflect
these corrections.
I In general, the in-place dry density test results indicate that the fill soil has a dry density of least 90
percent of the laboratory maximum dry density near to slightly above optimum moisture content at
the locations tested. In addition, moisture tests performed in "soil-rock" or "rock" fills generally
I indicate moisture contents at or above optimum. The approximate locations of the in-place dry
density and moisture content tests are shown on the As-Graded Geologic Map (Figure 1).
Laboratory tests were performed on samples of material used for fill to evaluate moisture-density
I relationships, optimum moisture content and maximum dry density (ASTM D 1557-00), expansion
potential (ASTM D 4829-95), and water-soluble sulfate content (California Test No. 417). The
results of the laboratory tests are summarized on Tables II, ifi and IV.
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Slopes
I The project slopes consisted of cut and fill slopes constructed at inclinations of 2:1
(horizontal:vertical) or flatter, with maximum heights of approximately 20 and 10 feet, respectively.
I All slopes should be planted, drained and maintained to reduce erosion. Slope irrigation should be
kept to a minimum to just support the vegetative cover. Surface drainage should not be allowed to
I flow over the top of the slope. It should be noted that the toe of the cut slope located south of the
subject lot has temporarily been cut near vertical to accommodate for the construction of the
proposed retaining wall in this area.
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1 Subdrains
Subdrains were installed at the general locations shown on the As-Graded Geologic Map (Figure 1).
In addition, the subdrains were "as-built" for location and elevation by the project civil engineer. The
subdrains generally consisted of a 6- to 8-inch diameter PVC perforated pipe placed in crushed
I aggregate surrounded by Mirafi 140N (or equivalent) filter fabric. The drains were typically placed
at least 15 feet below grade and constructed at a gradient of at least 1 percent.
During construction, the subdrains were generally outlet into storm drain structures. The final
subdrain system, which services Lot 103, ultimately outlets near La Costa Avenue at an energy
dissipater headwall. The canyon subdrain outlets should be maintained regularly to prevent sediment
and debris from obstructing the free flow of water out of the subdrain system.
Finish Grade Soil Conditions
I Observations and laboratory test results indicate that the prevailing soil conditions within the upper
approximately 3 feet of finish grade have an expansion potential of "low" (Expansion Index of 50 or
I less) as defined by Uniform Building Code (UBC) Table 18-I-B. It should be noted that although
rocks larger than 6-inch diameter were not intentionally placed within Zone A, some larger rocks may
exist at random locations.
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A representative sample of finish grade soils was subjected to water-soluble sulfate testing to
I evaluate the amount of water-soluble sulfates. These test results are used to determine the potential
for sulfate attack on normal Portland Cement concrete. The test results indicate sulfate contents that
I correspond to "negligible" sulfate exposure ratings. Geocon Incorporated does not practice corrosion
engineering. Therefore, results of these tests should be reviewed by a corrosion consultant and
appropriate recommendations should be implemented during design and construction of proposed
I improvements. The results of the soluble sulfate tests are summarized on Table V.
I SOIL AND GEOLOGIC CONDITIONS
The soil and geologic conditions encountered during grading were found to be similar to those
I described in the project geotechnical report. Santiago Peak Volcanics (Jsp) were exposed at grade on
cut lots, cut slopes, cut areas within street right-of-ways, or in canyon cleanouts. Compacted soils
were placed in areas of fill and are designated as Qcf on Figure 1.
The enclosed As-Graded Geologic Map (Figure 1) depicts the general geologic conditions observed.
No soil or geologic conditions were observed during grading which would preclude the continued
development of the property as planned.
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Project No. 06105-52-06 - 5 - October 8, 2003
CONCLUSIONS AND RECOMMENDATIONS
1.0 General
1.1 Based on observations and test results, it is the opinion of Geocon Incorporated that the
grading to which this report pertains has been performed in substantial conformance with
the recommendations of the previously referenced project soils report and the geotechnical
requirements of the grading plans. Soil and geologic conditions encountered during
grading which differ from those anticipated in the project soils report are not uncommon.
Where such conditions required a significant modification to the recommendations of the
project soils report, they have been described herein.
1.2 No soil or geologic conditions were observed during grading that would preclude the
continued development of the property as planned. Based on laboratory test results and
field observations, it is the opinion of Geocon Incorporated that the fill soils observed and
tested as part of the grading for this neighborhood were generally compacted to a dry
density of at least 90 percent of the laboratory maximum dry density near to slightly above
optimum moisture content.
2.0 Future Grading
2.1 Any additional grading performed at the site should be accomplished in conjunction with
our observation and compaction testing services. Grading plans for any future grading
should be reviewed by Geocon Incorporated prior to finalizing. All trench and wall
backfill should be compacted to a dry density of at least 90 percent of the laboratory
maximum dry density near or above optimum moisture content. This office should be
notified at least 48 hours prior to commencing additional grading or backfill operations.
3.0 Seismic Design Criteria
3.1 The site is located within Seismic Zone 4 according to UBC Figure 16-J. Compacted fill
soils underlie the proposed buildings. For seismic design, the site is characterized as soil
type SD Table 3 summarizes site design criteria. The values listed in Table 3 are for the
Rose Canyon Fault, which is identified as a Type B fault. The Rose Canyon Fault is
located approximately 7 miles west of site. Table VI presents a summary of soil profile
type and the corresponding values from Table 3 should be used for seismic design.
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TABLE 3
SITE DESIGN CRITERIA
Parameter Value UIBC Reference
Seismic Zone Factor 0.40 Table 16-I
Soil Profile SD Table 16-J
Seismic Coefficient, Ca 0.44 Table 16-Q
Seismic Coefficient, Cv 0.64 Table 16-R
Near-Source Factor, Na 1.0 Table 16-S
Near-Source Factor, N 1.0 Table 16-T
Seismic Source B Table 16-U
4.0 Foundations
4.1 Due to the presence of significant differential fill thickness within the pad, Foundation
Category ifi is recommended for the proposed recreation buildings. We understand that a
post-tensioned foundation system will be used for the buildings.
4.2 The post-tensioned systems should be designed by a structural engineer experienced in
post-tensioned slab design and design criteria of the Post-Tensioning Institute (UBC
Section 1816). Although this procedure was developed for expansive soils, it is understood
that it can also be used to reduce the potential for foundation distress due to differential fill
settlement. The post-tensioned design should incorporate the geotechnical parameters
presented in Table 4, entitled Post-Tensioned Foundation Systems Design Parameters for
the particular foundation category designated.
TABLE 4
POST-TENSIONED FOUNDATION SYSTEM DESIGN PARAMETERS
Post-Tensioning Institute (PT!) Design Parameters Foundation Category Ill
Thornthwaite Index -20
Clay Type - Montmorillonite Yes
Clay Portion (Maximum) - 70%
Depth to Constant Soil Suction 7.0 ft.
Soil Suction 3.6 ft.
Moisture Velocity 0.7 in/mo.
Edge Lift Moisture Variation Distance 2.6 ft.
Edge Lift 1.15 in.
Center Lift Moisture Variation Distance 5.3 ft.
Center Lift 4.74 in.
Project No. 06105-52-06 - 7 - . - October 8, 2003
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4.3 Foundations may be designed for an allowable soil bearing pressure of 2,000 pounds per
square foot (psf) (dead plus live load). This bearing pressure may be increased by one-third
for transient loads such as wind or seismic forces.
I 4.4 The use of isolated footings that are located beyond the perimeter of the building
and support structural elements connected to the building is not recommended. Where this
condition cannot be avoided, the isolated footings should be connected to the building
I foundation system with grade beams.
I 4.5 No special subgrade presaturation is deemed necessary prior to placing concrete; however,
the exposed foundation and slab subgrade soils should be sprinkled, as necessary, to
maintain a moist condition as would be expected in any such concrete placement.
4.6 Consideration should be given to connecting patio slabs that exceed 5 feet in width to the
I building foundation to reduce the potential for future separation to occur.
I 4.7 Where buildings or other improvements are planned near the top of a slope steeper
than 3:1 (horizontal: vertical), special foundations and/or design considerations are
recommended due to the tendency for lateral soil movement to occur.
Building footings should be deepened such that the bottom outside edge of the
I footing is at least 7 feet horizontally from the face of the slope.
Swimming pools located within 7 feet of the top of cut or fill slopes are not
I recommended. Where such a condition cannot be avoided, it is recommended that
the portion of the swimming pool wall within 7 feet of the slope face be designed
with the assumption that the adjacent soil provides no lateral support. This
I recommendation applies to fill slopes up to 30 feet in height, and cut slopes
regardless of height. For swimming pools located near the top of fill slopes greater
than 30 feet in height, additional recommendations may be required and Geocon
I Incorporated should be contacted for a review of specific site conditions.
It should be noted that swimming pool excavations in undercut lots or lots with
I shallow fills will likely require heavy effort or blasting to remove rock.
Although other improvements that are relatively rigid or brittle, such as concrete
I flatwork or masonry walls, may experience some distress if located near the top of
a slope, it is generally not economical to mitigate this potential. It may be possible,
however, to incorporate design measures that would permit some lateral soil
movement without causing extensive distress. Geocon Incorporated should be I consulted for specific recommendations.
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4.8 Exterior slabs should be at least 4 inches thick and reinforced with 6 x 6-W2.9 x W2.9
(6 x 6-6/6) welded wire mesh. The mesh should be placed within the upper one-third of the
I slab. Proper mesh positioning is critical to future performance of the slabs. It has been our
experience that the mesh must be physically pulled up into the slab after concrete
I placement. The contractor should take extra measures to provide proper mesh placement.
Prior to construction of slabs, the subgrade should be moisture conditioned to at least
optimum moisture content and compacted to at least 90 percent of the laboratory maximum
I dry density.
I 4.9 All concrete slabs should be provided with adequate construction joints and/or expansion
joints to control unsightly shrinkage cracking. The design of joints should consider criteria
of the American Concrete Institute when establishing crack control spacing patterns.
4.10 Where exterior flatwork abuts the structure at entrant or exit points, the exterior slab
I should be dowelled into the structure's foundation stemwall. This recommendation is
intended to reduce the potential for differential elevations that could result from
I differential settlement or minor heave of the flatwork. Dowelling details should be
designed by the project structural engineer.
I 4.11 The recommendations of this report are intended to reduce the potential for cracking of
slabs due to expansive soils (if present), differential settlement of deep fills, or fills of
I varying thicknesses. However, even with the incorporation of the recommendations
presented herein, foundations, stucco walls, and slabs-on-grade placed on such conditions
I may still exhibit some cracking due to soil movement and/or shrinkage. The occurrence of
concrete shrinkage cracks is independent of the supporting soil characteristics. Their
occurrence may be reduced and/or controlled by limiting the slump of the concrete, proper
I concrete placement and curing, and by the placement of crack control joints at periodic
intervals, in particular, where re-entrant slab corners occur.
1 5.0 Retaining Walls
I 5.1 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
I of 30 pounds per cubic foot (pcf). Where the backfill will be inclined at no steeper than
2:1, an active soil pressure of 40 pcf is recommended. These soil pressures assume that the
backfill materials within an area bounded by the wall and a 1:1 plane extending upward
I from the base of the wall possess an Expansion Index of less than 50. For those lots with
finish grade soils having an Expansion Index greater than 50 and/or where backfill
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Project No. 06105-52-06 - 9 - October 8, 2003
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I materials do not conform to the above criteria, Geocon Incorporated should be consulted
for additional recommendations.
5.2 Unrestrained walls are those that are allowed to rotate more than 0.001H (where H equals
I the height of the retaining wall portion of the wall in feet) at the top of the wall. Where
walls are restrained from movement at the top, an additional uniform pressure of 7H psf
should be added to the above active soil pressure. For retaining walls subjected to
I vehicular loads within a horizontal distance equal to two-thirds of the wall height, a
surcharge equivalent to 2 feet soil should be added.
5.3 All retaining walls should be provided with a drainage system adequate to prevent the
I buildup of hydrostatic forces and should be waterproofed as required by the project
architect. The use of drainage openings through the base of the wall (weep holes, etc.) is
not recommended where the seepage could be a nuisance or otherwise adversely impact
I the property adjacent to the base of the wall. A typical retaining wall drainage system is
presented as Figure 2. The above recommendations assume a properly compacted granular
I (Expansion Index less than 50) backfill material with no hydrostatic forces or imposed
surcharge load. If conditions different than those described are anticipated, or if specific
drainage details are desired, Geocon Incorporated should be contacted for additional
I recommendations.
I 5.4 In general, wall foundations having a minimum depth and width of one foot may be
designed for an allowable soil bearing pressure of 2,000 psf, provided the soil within 3 feet
I below the base of the wall has an Expansion Index of less than 90. The proximity of the
foundation to the top of a slope steeper than 3:1 could impact the allowable soil bearing
pressure. Therefore, Geocon Incorporated should be consulted where such a condition is
I anticipated. The location of the wall footings, however, should comply with the
recommendations presented in Section 4.8.
1 6.0 Lateral Loads
1 6.1 For resistance to lateral loads, an allowable passive earth pressure equivalent to a fluid
density of 300 pcf is recommended for footings or shear keys poured neat against properly
I compacted granular fill soils or undisturbed natural soils. The allowable passive pressure
assumes a horizontal surface extending at least five feet, or three times the surface
generating the passive pressure, whichever is greater. The upper 12 inches of material not
I protected by floor slabs or pavement should not be included in the design for lateral
resistance. An allowable friction coefficient of 0.4 may be used for resistance to sliding
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I Project No. 06105-52-06 -10 - October 8, 2003
between soil and concrete. This friction coefficient may be combined with the allowable
passive earth pressure when determining resistance to lateral loads.
6.2 The recommendations presented above are generally applicable to the design of rigid
concrete or masonry retaining walls having a maximum height of 8 feet. In the event that
walls higher than 8 feet or other types of walls are planned, such as crib-type walls,
Geocon Incorporated should be consulted for additional recommendations.
7.0 Slope Maintenance
7.1 Slopes that are steeper than 3:1 (horizontal: vertical) may, under conditions which are both
difficult to prevent and predict, be susceptible to near-surface (surficial) slope instability.
The instability is typically limited to the outer three feet of a portion of the slope and
usually does not directly impact the improvements on the pad areas above or below the
I slope. The occurrence of surficial instability is more prevalent on fill slopes and is
generally preceded by a period of heavy rainfall, excessive irrigation, or the migration of
subsurface seepage. The disturbance and/or loosening of the surficial soils (as might result
from root growth, soil expansion, or excavation for irrigation lines and slope planting) may
also be a significant contributing factor to surficial instability. It is therefore recommended
that, to the maximum extent practical: (a) disturbed/loosened surficial soils be either
removed or properly recompacted; (b) irrigation systems be periodically inspected and
maintained to eliminate leaks and excessive irrigation; and (c) surface drains on and
adjacent to slopes be periodically maintained to preclude ponding or erosion. It should be
noted that although the incorporation of the above recommendations should reduce the
I potential for surficial slope instability, it will not eliminate the possibility, and therefore it.
may be necessary to rebuild or repair a portion of the project's slopes in the future.
1 8.0 Drainage
.I 8.1 Adequate drainage provisions are critical to the future performance of the project. Under
no circumstances should water be allowed to pond. The building pads and sheet-graded
areas should be properly finish graded so that drainage water is directed away from
I foundations, pavements, concrete slabs, and slope tops to controlled drainage devices.
8.2 All underground utilities should be leak free. Utility and irrigation lines should be checked
periodically for leaks for early detection of water infiltration and detected leaks should be
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repaired promptly. Detrimental soil movement could occur if water is allowed to infiltrate
the soil over a prolonged period of time.
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8.3 Landscaping planters adjacent to paved areas are not recommended due to the potential for
surface Or irrigation water to infiltrate the pavement's subgrade and base course. We
I 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
I 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.
I LIMITATIONS
The conclusions and recommendations contained herein apply only to our work with respect to
grading and represent conditions at the date of our. final observation October 3, 2003. Any
I subsequent grading should be done in conjunction with our observation and testing services. As used
herein, the term "observation" implies only that we observed the progress of the work with which we
I agreed to be involved. Our services did not include the evaluation or identification of the potential
presence of hazardous or corrosive materials. Our conclusions and opinions as to whether the work
essentially complies with the job specifications are based on our observations, experience and test
I results. Subsurface conditions, and the accuracy of tests used to measure such conditions, can vary
greatly at any time. We make no warranty, expressed or implied, except that our services were
I performed in accordance with engineering principles generally accepted at this time and location.
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We will accept no responsibility for any subsequent changes made to . the site by. others, by the
uncontrolled action of water, or by the failure of others to properly repair damages caused by the
uncontrolled action of water, The findings and recommendations of this report may be invalidated
I 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.
Should 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,
GEOCON INCORPORATED
Shane Rodacker
RCE 63291
SR:AS:dmc
(4/del) Addressee
Project No. 06105-52-06
VILLAGES OF LA COSTA - THE OAKS SOUTH
80 NEIGHBORHOOD 3.15- LOT 103
RECREATION CENTER
/ CARLSBAD, CALIFORNIA
4
SCALE: 1" = 50'
h95 /
II 324 /
/
0 00
LEGEND
89 Qcf ........ COMPACTED FILL
36 1. 9
Jsp ........ SANTIAGO PEAK VOLCANICS (Dotted Where Buried)
APPROX. LOCATION OF GEOLOGIC CONTACT
/ FG-31350 LOCATION OF IN-PLACE DENSITY TEST
9:r-' Finish Grade ST...SlopeTest SZ...SlopeZone
APPROX. LOCATION OF SUBDRAIN
A 288 .......APPROX. ELEVATION OF SUBDRAIN
/ E1........APPROX. BOTTOM ELEVATION OF FILL 1/
K
/ GE000N
INCORPORATED
r GEOTECHNICAL CONSULTANTS
( L+ 6960 FLANDERS DRIVE - SAN DIEGO, CALIFORNIA 92121- 2974
PHONE 858 558-6900 - FAX 858 558-6159 Fj-7-6--2-1 PROJECT NO. 06105 - 12 - 06
FIGURE 1
AS - GRADED. GEOLOGIC MAP DATE 10-08-2003
E:/2003/LOT-103/6105_SRWWG/cml
GROUND SURFACE
2.0
iL CONCRETE
BROWDITCH
PROPOSED
GRADE
PROPOSED
RETAINING WALL - COMPACTED
BACKFI
3/4
MAFI 140 FILTER FABRIC
(OR EQUIVALENT)
a a• (
2/3 II - -_ I OPEN GRADED
1 MAX. AGGREGATE
.: 5'MAX.
FOOTING f 4 DIA. PERPORATED PVC
PIPE MIN. 1/2% FALL TO I APPROVED OUTLET
NO SCALE
I TYPICAL RETAINING WALL DRAIN DETAIL I
GE000N Q INCORPORATED
GEOTECHNICAL CONSULTANTS
6960 FLANDERS DRIVE - SAN DIEGO, CALIFORNIA 92121- 2974
PHONE 858 558-6900 - FAX 858 558-6159
SR/AML DSK/E0000
VILLAGES OF LA COSTA
THE OAKS SOUTH - RECREATION CENTER
CARLSBAD, CALIFORNIA
DATE 10-08-2003 1 PROJECT NO. 06105- 52-06 1 FIG. 2
D1DWGM4
- - - - - - - - - - - - - - - - - - - - Project No. 06105-12-06 TABLE I
FIELD DENSITY TEST RESULTS
Test
No. Date Test Location
1645 12/16/02 3.15 LOT 103
1646 12/16/02 3.15 LOT 103
1647 12/16/02 3.15 LOT 103
1664 12/19/02 3.15 LOT 103
1667 12/19/02 3.15 LOT 103
1668 12/23/02 3.15 LOT 103
M 1669 12/23/02 3.15 LOT 103
1744 12/31/02 3.15 LOT 103
1797 01/08/03 3.15 LOT 103
1987 02/01/03 3.15 LOT 103
1988 02/01/03 3.15 LOT 103
2387 04/28/03 3.15 LOT 103
2388 04/28/03 3.15 LOT 103
2390 04/28/03 3.15 LOT 103
2391 04/28/03 3.15 LOT 103
2391A 04/28/03 3.15 LOT 103
2394 04/28/03 3.15 LOT 103
2399 04/29/03 3.15 LOT 103
FG 3134 09/17/03 3.15 LOT 103
FG 3135 09/17/03 3.15 LOT 103
3218 10/01/03 3.15 LOT 103
3219 10/01/03 3.15 LOT 103
3251 10/03/03 3.15 LOT 103
3253 10/03/03 3.15 LOT 103
Elev. Plus Max. Opt. Field Field Field Req'd
or 3/4" Dry Moist. Dry Moist. Re].. Rel.
Depth Curve Rock Dens. Cont. Dens. Cont. Comp. Comp.
(ft) No. (%) (pcf) (%) (pcf) (%) (%) (%)
298 8 60 139.6 5.9 131.7 9.8 94 90
300 8 60 139.6 5.9 127.2 10.3 91 90
301 8 60 139.6 5.9 128.5 8.8 92 90
302 8 60 139.8 5.8 126.8 7.9 91 90
305 8 60 139.6 5.9 125.3 10.1 90 90
308 8 60 139.6 5.9 128.7 10.7 92 90
310 8 60 0.0 5.9 0.0 10.3 0 0
315 9 60 141.3 5.7 136.7 5.9 97 90
310 8 60 139.6 5.9 128.8 6.8 92 90
322 8 20 128.5 9.7 121.3 12.2 94 90
324 8 30 131.3 8.7 119.2 13.3 91 90
319 8 10 125.8 10.8 118.6 11.3 94 90
322 8 40 134.1 7.7 122.8 7.5 92 90
326 8 30 131.3 8.7 120.4 9.3 92 90
329 8 0 123.0 11.9 110.0 9.0 89 90
329 8 20 128.5 9.7 116.3 10.1 91 ' 90
331 8 10 125.8 10.8 113.6 12.1 90 90
330 8 30 131.3 8.7 120.6 9.7 92 90
334 8 30 131.3 8.7 120.9 7.8 92 90
334 8 30 131.3 8.7 119.4 8.5 91 90
356 8 30 131.3 8.7 119.4 9.3 91 90
359 8 30 131.3 8.7 118.0 9.3 90 90
362 8 30 131.3 8.7 118.5 8.5 90 90
364 8 30 131.3 8.7 117.8 9.6 90 90
Note: See last page of table for explanation of coded terms
TABLE II
SUMMARY OF LABORATORY MAXIMUM DRY DENSITY
AND OPTIMUM MOISTURE CONTENT TEST RESULTS
ASTM 0 1557-00
Sample Maximum Optimum
Moisture
No. Description Dry Density Content (pci) (% dry weight)
8 Reddish-brown, Gravelly, fine to coarse SAND 123.0 11.9 with trace silt
Reddish-gray, Sandy, fine to coarse GRAVEL 126.9 10.7
with trace clay
TABLE III
SUMMARY OF AS-GRADED BUILDING PAD CONDITION AND FOUNDATION
CATEGORY FOR VILLAGES OF LA COSTA -THE OAKS SOUTH
NEIGHBORHOOD 3.15— LOT NO. 103
Approximate Approximate
Lot Maximum Maximum Depth Expansion Foundation
No. Pad Condition Depth of Fill of Differential Fill Index Category
(feet) (feet) -
103 Undercut due to 46 20 33 III
cut/fill transition
TABLE IV
SUMMARY OF LABORATORY WATER-SOLUBLE SULFATE TEST RESULT
VILLAGES OF LA COSTA -THE OAKS SOUTH
NEIGHBORHOOD 3.15 - LOT NO. 103
CALIFORNIA TEST NO. 417
Sample No. Water-Soluble Sulfate (%) Sulfate Exposure
5-1 0.017 Negligible
Project No. 06105-52-06 October 8, 2003