HomeMy WebLinkAboutCT 02-07; EMERALD POINTE ESTATES; REPORT OF ROUGH GRADING OBSERVATION, SOIL TESTING, AND GEOTECHNICAL ENGINEERING; 2006-07-11S
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Geotechnical
Exploration, Inc.
I 4Gi Oeotethnical Exip'l oration, mc;
I . SOIL AND FOUNDATION ENGINEERING • GROUNDWATER ENGINEERING GEOLOGY.
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11 July 2006, ,. ..
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RWR Homes, Inc Job No 97-7189
2710.LokerAvenue West, Sijite.350.
Carlsbad, CA 92010
I Attn: Mr. Brendan Farrelly -
Subject: Renort of Rough Grading Observation, Soil Testing and '
GéotechnicajEngineering
- Emerald Pointe Estates Project, APN212-040-50 ' . "•. .
North :of the West End of Sapphire Drive
Carlsbad, California . , . .. . .
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Dear Mr. Farrelly
I As requeted, Geotechnical Exploration, mc, hereby submits the followir
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report summarizing our, work and test results, as well as our conclusions and
* ', .• recommendations concerning the subject 4pr03ect. A representative of our firm
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' observed the recently completed rough grading operation and has tested the fill
soils that were removed and recompacted during the. rough grading of the building
, pads, and: perimeter retaining walls
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I The grading described herein consisted of removing and recom patting 4topsos, and
placing and compacting fill soils, undercutting and placing compacted soils;.,and
I cutting soils for exterior perimeter retaining walls The grading reported he was
observed and/or tested between March 31, 2006, and June' 1,,'2006.
SCOPE OF WORK
• :.Th scop&of work of our services included:
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1 Observations during rough grading of the site
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7420 TRADE STREEI• SAN DIEGO, CA. 921211 (858) 549-72221 FAX (858) 549-16041 EMAIL geoted'i@ixpres corn
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Emerald Pointe Estates Project Job No.-,97-7189
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2 Performing field density tests in the placed and compacted fill
1 3... Performing laboratory tests on representative samples of the fill material
I 4. Providing professional opinions, conclusions, and recommendations regarding
the observed grading and the pending 'work.
GENERAL SITE INFORMATION
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The property, consisting of approximately 18 acres, is known as Assessor's Parcel
No 212-040-50, and is located at the north end of Sapphire Drive, in the City of
Carlsbad (see Figure No I) The property is bordered on the north by undeveloped
I land, on the south by the Greystone/Cobblestone residential development, on the
east by similar undeveloped land and Sire Drive; and on the west by
Cobblestone Road
I Prior to grading, the property was used for agricultural purposes The property
sloped 'moderately to steep ly' down, to the north and west from ,a gently sloping
I ridge top in the southern portion of the property.. Approximate elevations across
the site ranged from a high of 262 feet Above Mean Sea Level (AMSL) to 100 feet
I AMSL Mapped survey information of the achieved pad elevations was not available
at the time of preparation of this report, however, we assume they are very close to
I the ones shown in the approved grading plan. •. :
I Vegetation on the site prior to grading consisted of wild grasses on the flat areas,
with some thick shrubbery and chaparral on the slope areas Access to the
I property waSIr provided via the north terminus of Sapphire Drive
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EmeraldPointe Estates Project Job No 97-7189
Carlsbad, California Page 3
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I Existing structtdres prior 4t0 grading included several high-voltage power
transmission lines extending along the north-south direction through the northwest
I portion Of the site 4.
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I .-. The building pad areas have been prepared to receive thè foundations of the
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homes, which will be a maximum of two stories in height It is our understanding
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that thei homes will be constructed in conformance with the California Buildin5-g
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Code, utilizing shallow foundations on post-tensioned slabs, footings, &nd *
I conventional building materials A Plot Plan illustrating the approximate location of
all our tests taken throughout the reported grading operation is enclosed as Figure
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I Work that remains to be completed at the site and that will require our obsrvations
and/or testing include any pending retaining wall backfill, trench backfill, and final
I subgrade and base preparation of areas to receive pavement, and exterior rigid
improvements
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FIELD OBSERVATIONS
Periodic tests and observations were provided by a representative of Geotechnical
I Exploration, Inc to check the grading contractor's (C E Wilson Corporation)
-,compliance with the grading specifications The presence of our field representative
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at the site was to provide to the client continuing source of professional advice,
opinions, and recommendations based upon the field representative's observations
of the cdntractor's work, and did not include any superintending, supervision, or
direction of the actual work of the contractor or the contractor's workers Our visits
were made on request of the contractor's or developer's representative
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', Emerald" Pointë Estates Project ' Job No. 97-7189
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I ' The grading operation was observed to be performed' in the following general'
manner:
1• ," ' " S is Prior.to placing any compacted fill, the areas to be graded were cleared of
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surface trash,' miscellaneous debris, and/or vegetation, and hauled off-site.
"2. Topsoils, soft or disturbed materials were removed to expose firm ground.
The project grading started near the nórthWest area of the site.
Approximately 2 to 3 feet of topsoils were removed in the' northwest area.
where grading began The topsoils had excessive water content in their
natural state' and, therefore, were allowed to dry. Two rows or perforated
'subdra,in pipes were placed at the approximate locations' shown in the
attached-plot plan (see Figure No. I). A keyway was ,excavated into dense
formational soils prior to starting the, northern lot fill slope. The 'outlet of the
subdrain pipe extended 5 to 10 feet beyond the final' toe of the fill slope. The
subdrains of the northern fill slope were placed ,i,r.trenches' approximately
2'x2 in cross section. The subdrains consisted of SDR 35, 4-inch-diameter.
perforated pipes, in an envelope of crushed rock gravel, and wrapped with
filter cloth. Due to ,the wet soil conditions of the topsoils, drier imported soils,,
were mixed with a paddle-wheeled' scraper after placing a layer of imported
soils over a 'layer of wet topsoils. Concrete. piece from' Sapphire Court's
demolished sidewalk were broken down into 12- to 18-inch pieces and.
incorporated in the deeper fill areas of the project. A 12-inch7thick layer of
concrete pieces was placed in Lots 9 through',11, at elevations of 234 to 236
AMSL, and compacted with a water 'truck ,'by wheel 'rolling and then rolled
over with an excavator. A layer, of soil was placed' on' top Of the compacted
concrete pieces and wheel rolled with a water truck and rubber tired loader.
Soils with 'moisture, contents below -the required content were watered with a
water truck to increase, moisture. The,. moisture content in the upper 10 feet .
Emerald Pointe Estates Project Job No. 97-7189
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I - of fill lots and overexcavated soils were increased to 5 percent over optimum
The masonry retaining wall excavation was made to provide a backfill
I horizontal distance equal to one half of the wall soil retaining height The
backfill of the retaining walls should consist of imported low expansive soils
I The Sapphire 'Drive area into the property was lowered 5 to 7 feet Mixing
soiIs and getting uniform soil moisture conditions was difficult on Lots 7
I , through 13 In some areas (such as in Lots 5 through 9), soil remixing was
implemented to achieve uniform soil moisture conditions Lots 1 through 4
I were undercut 3 feet The excavated soils were moisture conditioned and
recompacted The roadway area was cut down to approximately 2 feet below
I finished surface Berms at the top of slopes were built with approximate
dimensions,,of 12 to 18 inches high and 24 inches in width'..Finish grade
I testing was completed on June 1, 2006 Surplus soils stockpiled on Lots 1
and 2 were exported off site on May 31, 2006
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3 Grading equipment used during rough grading of the property included
paddle-wheeled scrapers, a rubber tired compactor, a Wabco, an excavator,
bobcats, belly dumpsters, a water truck, a rock breaker, a D-5 Cat dozer,
1 and a D-9 Cat dozer
4 A desilting basin was excavated in the eastern area of the project, td the east
Of Lot 1 Erosion control measures were completed once the finish grading
I was completed
5 Soil samples were obtained from the pad finish subgrade for expansion index
tests and soluble sulfate tests Expansion index tests indicated that the soils
I range from highlyL to very highly expansive Soluble sulfate tests indicate
that the soils have a moderate to high potential for damaging cement
I Cement type \i should be used in the concrete, and/or a low water-cement
Emeáld Pointe Estates Project. . ' . Job No. 97L7189.
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I ratio. Test results for Expansion Index and -Soluble Sulfate tests have been
previously presented in' a separate' letter (see Appendix A).'.
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One R-value test was performed on. .a typical soil sample obtained from close
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to thê subgrade elevation of Sapphire Drive'. This soil test yielded an, R-value '
-,result of 11. Replacement of the.upper 1.foot of subgrade soils with a better
I . ' quality subgrade soil will help reduce the pavement cross section. '
Areas to receive compacted fill were, in general, observed and evaluated by
our field representative prior to placing compacted fill. In slope fill areas,
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adequate' benching was provided by keying into competent natural ground as
the compacted fill was 'placed above the toe, area. '.The' removal and
1 recompaction outside the toe of fill slopes and toe of retaining walls extended
4to5feet.
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.. Soils approved for use in the compacted fill were placed; in horizontal layers
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. not exceeding approximately 8 to 10 inches in loose thickness where heavy
compaction equipment was ,used,' and in 'thinner layers where lightweight.
I ' compaction equipment was. used.
Fill' material 'was watered or dried at a moisture content at least 3 percent
over the optimum in fill soils placed below 10 feet from the ground surface.
For clayey fill soils placed within 10 feet below the ground surface, 'the soils
were moisture conditioned to at least 5 percent over the optimum moisture
I ' content and mixed prior to compaction.
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10.' The soils utilized in the grading operation were from', on-site and imported
and' consisted primarily of dark brown silty clay, dark gray-green siltstone
Emerald Pointe Estates Project .. . Job No. 97-7189
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1 with clay, brown clay; imported yellow-brown sandy silt,formational yellow-
brown clayey, sands, and mix of light brown clayey silt.. .
11. Fill materials weretested at specific ,test locations and found to be compacted
I at the tested locations to at least 90 percent of Maximum Dry Density Areas
with failing test results were pointed., out to the contractor for corrective
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' work. Those areas were approved, after corrective work was performed and
satisfactory test results were obtained. ' V. ,•
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12. The method used to compact the slope fill surface consisted of. compacting
I the fill mass and later walking the slope surface with a track-mounted dozer..
I 13. Retaining walls'. 'were pending construction at the time of our site visit
. prior to preparation of this repOrt (June 1, 20,06).
14. Field density, tests were taken at the approximate locations shown on the plot
I plan (Figure No. II). •. ' • . . .
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I TESTS
I lield density tests were performed in accordance with ASTM D2922 Maximum
density determinations were performed in accordance with ASTM D1557. The •
relative compaction results, as summarized on Figure No III, are the ratios of the
field densities to the laboratory Maximum Dry Densities, expressed as percentages. V
In additi6n, we performed Expansion Index Tests in accordance* With UBC 29-2 and V
Water Soluble Sulfate potential for the building pads, in accordance with CAL test
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NO., 417 An R-value test on a representative soil sample of subgrade soils for the
area of Sapphire Drive to be paved was performed in accordance with CAL test No.
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V. I 301 Test results for Expansion Index, soluble sulfates and R-value have been
already presented in separate reports (see Appendix A)
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- . CONCLUSIONS AND RECOMMENDATIONS ..• -
I The following conclusions and recommendations are based upon our analysis of all
I data available from the testing of the soils compacted on this site Our
observations of the grading operation (while in progress), our field and laboratory
I testing of the typical bearing soils, and our general knowledgend experience with
the natural-ground1 soils and recompacted fill soils on this site were utilized ,in
I conducting our services
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A General Gradina -
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1 The soils utilized in the grading operation were from existing on-site soils that
were removed an& recompacted, and impoi-ted materials that were placed
I and recompacted The soils consisted primarily of silty clays, siltstone with
clay, clays, sandy silt, silts, and clayey. silts Clayey soils are considered to
1 range from highly xpansive to very highly expansive, as measured by the
BC'Expansin Index Test (29-2 standard) Refer to the attached table on
I Figure No Ills Representative sofl samples were obtained for expansion
index tests from soils exposed élvátioruin the building pad areas
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and yielded highly expansive expansion indices
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1 2 During the rough grading operation, the natural-ground soils were exposed
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(where necessary) and properly prepared to receive the fill soils The fill soils
I were placed, watered, compacted, and then tested at specific test locations,
and were found to be compacted attIe tested locations to at least-, 90,
percent of Maximum Dry Density, inccordance with the requirements of the
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I ON of Carlsbad The maximum depth of fill soils placed on this site at the
) time of the grading operation monitored by this firm was not in excess of
I I' approximately. 25 feet in vertical thickness in the deepest part of the
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northwest fill slope areas (see plot plans for elevation of excavation
I bottoms)
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I 3 Any surplus, looe, stockpiled m soils reaining at the property should be
removed and hauled off the site 1
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4 Grading work that needs to be complete& and Eperformed under our
I obsevations and testing includes retaining wall backfIll, trench backfill, and
finish subgradeand base preparation in areas to receive pavement and/or - - •-- ---.-•. - -,'* . - - -
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B - Foundations and Slabs On-Grade
5 Due to the highly expansive nature 1 0f the c6mpacted fills, the continuous
foundations and spread footings should extend a minimum depth of 30 inches
I into the properly compacted fill for,-'Structures shorter or equal to two stories
in height, and have a minimum width of 12 inches or as required in the
I foundation plans The continuous foundations -and isolated foundations
should be reinforced as indicated in the foundation plans Additional steel
I reInforcing may be required by the structural engineer in deeper footings
After grading, the soils in the building pad areas or areas to receive concrete
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should be irrigated with sprinklers at least¼ 10 minutes every 2 days
Irrigation should be maintained until the foundations and slab concrete is
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6 Prior to pouring footings and foundations, and prior to placement of floor slab
base sections, any clayey soils should be thoroughly watered such that they
approach their maximum potential for expansion! We recommend that the
clayey 'subgrade soil be presoaked to achieve moisture content at least 5
I percent above optimum to a depth bf at. léast..pne foot below the bottom of
slab and footings The subgrade moisture content and penetration should be
verified by our field representative 48 hours prior to concrete pouring. The
bottom of the foundation excavation should be flrm, not muddy, and have
I the acceptable moisturecontent. ..
Concrete floor slabs should be founded on,,,at least 2 inches of sand overlying
a moisture barrier on 2 inches Of and,.on properly, compacted subgrade.
1 The slabs should be reinforced per the structural plans for post-tensioned
slabs for the project. Proper suppoits-should be used to keep the, steel
reinforcement separated from. the base or soil subgrade. Garage slabs
should be provided with at least 4 inches of properly compacted sand with a
mid-thickness vapor moisture barrier or properly compacted base material
We recommend that all nonstructural concrete slabs (such as patios,
sidewalks, etc), be founded on properly compacted and prepared on site m
expansive soils with moisture.. conditioned verified prior to concrete
placement Proper shrinkage joints (sawcuts) should be provided and spaced
I no farther than 25 feet for properly reinforced slabs with No. 3 steel bars;
and no farther than 15 feet apart, if they are. reinforced with 6/6-6x6 steel
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welded wire fabric. Control joints should also be provided at re-entrant • .
corners The sawcuts should be performed within 12 hours after, pouring, or
I as soon as the concrete is set Sawcuts should be deepened to at least one-
• tion joints quarter of the thickness of the slab; Sawcuts and isola should bel
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I sealed with elastomeric joint sealant to help control runoff water infiltration in
the subgrade areas beheath the slab
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9. All concrete (flatwork) slabs or rigid improvements should be built on
I properly compacted and approved subgrade and/or base material Due to the
.,highly expãnive nature of the soils, have previously recommended that
- exteri6r slabs be placed on at least 12 inches of low expansive soils on
properly compacted on-site soils.'Geotechnical Exploration, Inc. will
I accept no liability for damage to flatwork or rigid improvements built on
untested or -unapproved subgrade or base material. After rough grading is
I completed, subgrade soils to receive improvements bcome disturbed due to
trench excavations, moving of construction equipment, weather, etc The
I disturbed soils lobse compaction and need to be reco,!idit,oned before
.concrete or rigid improvements are placed on them. -
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C. Foundation -Design Parameters -.
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10 The recommended allowable soil bearing capacity of the properly compacted
I fill soils placed on site is 21000 pounds per square foot (psf), and 3,000 psf
for foundations Iaced on frmation. These soil-bearing ' values may be
increased ône-third for design loads that include wind or seismic analysis
Additionally, these bearing capacities may be utilized in the design of
I foundations and fóotins' 0f the proposed structures when founded ',,a
minimum of 30 inches into the firm natural ground or compacted fill for up to
I two-story structures For on-site conditions, it is expected that the maximum
settlement or uplifting should be within acceptable limits The angular
I rotation of the building foundations and floor slabs are anticipated to have a
maximum angular rotation that will not exceed 1/240
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I 11 The passive earth pressure of the encountered natural-ground soils and well-
compacted fill soils (to be used for design of building foundations and
footings to resist the lateral forces) should be based on an Equivalent Fluid
Weight of 275 pounds per cubic foot This passive earth pressure should only
be considered valid for design if the grourd adjacent to the foundation
structure is essentially level for a distance of at least three times the total
I depth of the, foundation, the soil is properly compacted fill or natural dense
material, and the concrete is poured tight against the walls of the excavation
- 12. A Coefficient of Friction of 0.35 times the dead load may be used to calculate
I the total friction force between the bearing soils and-the bottom of concrete
- wall foundations, or structure foundations, or floor slabs. -
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D. Retaining Wall Design ParaméterS
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13. The active earth pressure (to be utilized in design of cantilever -walls, etc.)
I should be based on a Equivalent Fluid Weight of 45 pounds per cubic foot (for
level backfill only and low-expansive, approved imported soils).
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. In the event that the cantilever retaining wall is surcharged by sloping •
backfill, the design active earth pressure should be' based on the appropriate
Equivalent Fluid Weight presented in the following table: -.
!! to 1O '52 "58"12"J3
I • *To determine design active earth pressures for ratios intermediate to those
presented, interpolate between the stated values
Emerald Pointe Estates Project Job. No. 97-7189
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In the event that a retaining wall isto be designed for a restrained condition,
a uniform pressure equal to 1OxH (ten times the total height of retained soil,
I considered in pounds per square foot) should, be considered as acting
everywhere on the back of the wall; in addition to the design Equivalent Fluid
I Weight
I In the event that imported, clean, granular fill soils'br approved, gravels are
to be utilized as backfill material, this firm should be contacted for possible
I ' reduction of design pressures due to level bakfill, 'sloping backfill, or
restrained wall conditions. The granular soils should be capped with 'a 12-
I inch-thick layer of on-site properly: compacted soiIs. .,,Additional surcharge
pressures to.-be considered in the wall design include any loads applied within'
I the failure block retained by the wall.
E. Cut and Fill Slopes S
14 Natural-ground cut slopes of maximum inclinations of 2.0 to 1.0 (horizontal
to 1.0 vertical), and compacted fill slopes of maximum inclinations of 2.0
I horizontal to 1.0 vertical, should be stable,and free from deep-seated failures
for materials native to the site Or imported soils utilized in compacted fills.
15. Although the compacted fill soils have been .'erified at the tested locations to
I have a relative compaction of 90 percent of Maximum Dry Density or better,
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the compacted highly expansive fill soils that occur within 10 feet of the face • '
of the fill slope may posses poor lateral stability. If not properly founded, the
proposed structures 'and associated 'improvements (such as walls, fences, • S S
patios, sidewalks, swimming 'pools;'driveways, asphalt paying, etc.) that are
located within 10 feet of the face of compacted fill slopes could suffer
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differential. ii9vmentas a result of the poor lateral stability of these highly,
•. exansive soils.
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-- The foundations and footings of the proposed, structures, fene posts, walls,
I etc, when founded 10 feet and farther away from the top of compacted fill
slopes, may, be of standard design 1nconformance with the recommended
I soil value If proposed foundationsand footings are located closer than 10
feet'inside the top of compacted fill slopes, they should be deepened to at
last 2 feet below a liné.beginning at apoint 10 feet horizontally inide the fill
1opes, and projected outward and ,doWrward, parallel to the.face of the fill
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' slopes (see Figure No. IV). Based on a review of a house 'location plan, by
Hunsaker and Associates, we understand that no house foundation will be
closer than 10 feet from slope top. Any swimming pool or other rigid
improvement should be founded considering potential soil movement on the
I outer 10 feet of slope Other recommendations presented in our previous
reports for the project for rigid improvements remain applicable, unless
I superseded in writing by our firm
I 16 It is recommended that all compacted fill slopes and natural cut slopes b
planted with an erosion-resistnt plant, in conformnce with the
I requirements of th6 City of Carlsbad
F Drainage
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I 17 Adequate measures should be taken to properly finish-grade the site after
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the structures and other improvements are in place. . We have
I recommended, that a gradient of 5 percent (3 inches fall) be used within 5
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feet from the perimeter of the residence Drainage waters from this site and
adjacent properties are to be directed away from foundations, floor slabs,
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Emerald Pointe Estates Project Job No. .97-7189
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I footing, and slopes, onto the natural drainage direction for this area or inkto
properly designed and approved drainage facilities Roof 4gutters and
I downspouts should be installed on all structures, and the runoff directed
away frorn the foundation via closed dfainage.iines.: Proper subsurface and
I sukace drainage will help minimize the potential for waters to seek the level
of iihe bearing soils under the foundations, footings, and floor slabs Failure
I to observe this recommendation could result in.,,uplift or undermining and
differential settlement of the structure or other improvements on the site
I Sufficieht and effectively working area drains shduld be installed around the
homes to quickly, dispose off runoff water.
18 Proper subdrains should be installed behind all retaining and restrained
I retaining walls, in addition to proper waterproofing of the back of the walls
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Th drainage of said subdrains should be directed to the designed4drainage
for the project or the natural drainage for the4 area
I 19 It should be noted that changes of surface and subsurface hydrologic
conditions, plus irrigation of, ,landscaping or significant increases in rainfall
over the "accepted average-annual" rainfall for San Diego County in past
4 years, may result in the apparance of minor amounts of surface or near-,
surtaceiwater at locations where none existed previously. The damage from
.such water Is expected to be minor and cosmetic in nature, if corrected
I . imr1iediately. Corrective action should be taken on a site-specific basis if, and
wh'en, it becomes necessary.
20 Plarter areas, flower beds, and planter boxes should be sloped o drain away
I - fromthe foundations, footings, and floor slabs Sufficient and properly,
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functional area drains should be placed around the apartment buildings and
in landscape areas where excessive runoff may cause damage to
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I improvements. Planter bOxes should be constructed. with a sealed bottom,
and be provided a subsurface drain installedJn gravel, with the direction of
I subsurface and surface flow away from the fouhdations, footings, and ,floor
slabs1 to an adequate drainage facility.
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21. Any bckfill soils placed adjacent to or: close to foundations, in utility
trenches, or behind retaining walls, that: support structure and other
improvements (such as patios, sidewalks, driveways, pavements, etc), other
I than landscaping in level ground, should be compacted to at least 90 percent
of Maximum Dry Density. It is recommended. that Geotechnical
I Exploration, Inc. observe and test the backfill, during placement. '
I Geotechnical Exploration, Inc will accept no liability for damage to
structures that occurs as a result of improperly, backfilled trenches or walls;
I or as a result.of fill soils placed without our observations and testing.
I G. Miscellaneous Recommendations'. '
I 22. Following placement of concrete floor slabs, sufficient drying time must be
allowed prior to placement of floor coverings. Premature placémént of floor
I coverings may result in degradation,of adhesive materials and loosening of
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the. finish_floor materials. '
23 Swimming pools and/or: subsurfatel structures that are founded in any
1 potentially expansive clay soils should be properly designed by a structural
'engineer and/or soils engineer.
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24. The remaining, soil work to be completed at the site (such as pending or
untested trench and retaining wall backfilling, finish subgrade' and base •
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Emerald Pointe Estates Project Job NO. 97-7189
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I preparation for . areas to receive pavement and or exterior rigid
V " improvements, etc.) should be performed under our observations and
I testing. V
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It is also recommended tht all footing excavations be observed by a
representative of this firm prior to placing
11 concrete, to verify that footings are
V founded on satisfactory soils for which the recommendations expressed in the V
V soil investigation report remain applicable.,V V
V V V
V
V SUMMARY
I
V Based on our field testing and grading observation,: it is ouVr opinion that the rough
I grading operation described herein, in general, Was performed in conformance with
the City ofCarlsbad Grading Ordinance; It to be understood that our test results
1 V '
and opinion of general acceptance do flot guarantee that every cubic yard of
compacted fill has been compacted to specification since not every cubic yard has
I been observed or tested. Our test results, indicate the V measured compaction
degree obtained at the specific test location. We can only, attest that our tests and
I observations have been made in accordance with the care and current professional
V
standards in our field.
V All 'observed or tested work done during the grading operation'appears, in general, V
to have been performed in accordance with the soil investigation report for this site,
V issued by our firm and dated April 30, 2002 '(Job No. 97-7189), and subsequent
I addenda. The grading described herein was observed' and/or tested between March
31, 2006, and June 1, 2006
I "All statements, in the report are applicable only for the grading operation observed
by, our firm, and are representative of the site at the time of our final site 'visit '' V
4 )
I Emerald 'Pointe Estates Pro)ëct .: . Job No. 7-7189
I
Carlsbad, California Page 18
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4 - - -
I before te report was prepared The firm of Geotechnical Exploration, Inc shall
4 riot be held responsible for fill soils placed without our observations and testing at
any other time, or for subsequent changes to the site by others, which directly hr
indirectly cause poor surface or subsurface drainage,., water erosion, and/or
I alteration' of the strength of the compacted fill soils
-. -
-.
In the event that any changes in the nature, design, or location of the buildings or
improvements are planned, the conclusions and recommendations contained in this
I report should not be considered valid unless the changes are reviewed and the
I
:
conclusions of this report modified or verified in writing
- •- ... .,, 4 .-
/ Professiorial opinions presented herein have been made based on our tests,
I observations, and experience, and they have been made in accordance with
generally accepted current,geotechnical engineering principles and practiceNithin
I the County of San Diego This warranty is in lieu of all other warranties, either
expressed or intended
I
Thank you for this opportunity to be of service Should any questions arise
concerning this report, please do not 4hesitate to cdntact us Reference to our Job
I
No 97-7189 will help to expedite a reply to your inquiries
-4
4
Respectfully submitted,
GEOTEC.HNICAL1 EXPLORATION, INC.%OFESSIO
I
cc Addressee (4)
1
26707
/
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' t 4
VICINITY .MAP
Figure No. I .
Job No. 97-7189
SPIN
H
I
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COMPACTION TEST RESULTS'
RELATIVE DEPTH! MOISTURE FIELD SOIL
TEST DATE LOCATION ELEVATION (%) DENSITY TYPE ,COMPACTION
OF FILL (ft)
I l' 4/7/06 Lot 10 , 218 23.0 97.0 2 91%
2 4/7/06 Lot 10 220 24.4- 98.0 2 92%'
-
3 4/10/06 Lot 10 222 206 1101 0 1 90%
I - 4 4I1/06 Lot 10 223 23.7'." 96.0 .,2:,, 90%."
5 4/10/06 Lot 10 225 U.3 101 0' 1 90%
Lot 10 ,- - ' 226 -' 27.1 960' 2
'
- 7 4/11/06 Lôt11 , : 226 26.2 ' 97.0 3 - 86%. Fail -
8 4/11/06 'Retest#7 , 226 22.0 102.0 3 90%
9 4/12/06 Lot 10 ' ' ' 228 19.0 .''102.0 '3 90%:
10 4/12/06 Lot 10 229 20.4., 1010 6 92%
4/12/06 Lot 233 226 970 2 91% I ll
12 4/13/06' Lot 10 232 ,, 22.6 ,- 97.0 ' 6 87% Fail
13 '4/13/06 Lot,10 . ' 233 26.1 97.0 ' 'S '. .90%
I 14 4/13/06 Retest#12 232 238 1010 6
'15 4/13/06 Lot 11 ' , '. .233 ."'17.2 104.0 .,. 4 92% . . .. -
. 16 4/13/06Lot 9 " - 234 . '22.7 960 ' 2 90%- I 17 4/17/06 Lot 235 176 ' 1020 4 90%
18 4/17/06 Lot 10 234 271 970 2 91%
I 19 4/17/06 Lot 10 234 226 970 3 86% Fail
20 4/17/06 Retest #19 234 22.8. 96.0 2 90%
21 4/19/06 Lot
,
, . 236 -.21.2 103.0,. 3 9'1% ,
- 22' 4/19/06 Lot 10 . 235 22.6 , 96.0. 2 ' 90% ,
23 4/19/06 Lot 11 235 201 1030 3 91%
I
,;.24.4/20/06 Lot 10
, ' , ' 236'- 21.6 ' 99.0 , 2" 93%
25 4/20I06 - Lot 9 - ' 238 17.5 . 104.0 4 -' 92%
26' 4/21/06 Lot 11 - 236 .23.0 98.0 - 2 ' 92%.
27' 4/21/06 Lot 10 : - 237 22.4 , 99.0 2 93%
28 4/24/06 Lot 11 237 209 1000 2 93%
I 29 4/24106 Lot 10 239 21.2 93.0 2 87% Fail
30' 4/24/06 •, Lot 12 , 237 - 24.1 96.0 2 90%
31 4/24/06 ' ' Lot 9 ' , - . 240 23.6 97.0 2 91% "
32 4/25/06 Retest #29 ' , ' 239 26.2
-
96.0
,
2 90% ...
33 4/25/06 Lot 242 237 960 2 90%
.34 ' 4/26/06 Lot 11 . - 240 ' '23.1 '99.0 5 - 92% I '"35 4/26/06 Lot 1,0
-
, - . 240 ' 22.2 ' 100.0 ' '' 5 93% "
36 - 4/26/06 - ,' Lot 9 242 23.6 , . 99.0 5 ' 92% '
I ' .
--.: '''-..' '-." .''.- .'
- ' - Job No. 97-7189 ____
: :- , Figure lIla
I','
4'
4.
I
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COMPACTION TEST RESULT .
DEPTH! MOISTURE FIELD SOIL RELATIVE I TEST DATE LOCATION ELEVATION (%) DENSITY TYPE COMPACTION
OF FILL (ft)
37 4/27/06 Lot 12 241 232 1000 5 93%
38 4/27/06 Lot 9 243 24.0 98.0 -,,. 5 91%
39 4/27/06 Lot 10 243 24.1 95.0 5 88% Fail
46 4/28/06 Lot 11 244 236 97.0 ' 5 90%
41 4/28/06 Retest #39 243 246'99.0..,5 92%
42 4/28/06 Lot 245 230 980 5 91% I 43 5/1/06 Lot 12 245 224 97 .0, 5 90%
44 5/1/06 Lot 10 246 22.8 97 0 54 90%
I 45 5/1/06 Lot 8 246 23.8' 98 0 5 91%
46 5/2/06 Lot 9 246 246 98.6 5 91%
5/2/06 Lot 12 • 245 25 1 97.0 5 90% I 47
/ 48 5/3/06 Lot 8 246 ' 232 99.0 5 92%
4 . .
• 49 5/3/06 Lot 10 247. 23.5 99.0 5 •- . 92%
I 50 5/4/06 Lot 9 248 23 .ii 99 0 5 92%
•,: 51 5/4/06 Lot 11 247 24.0.. 97.0 5 90%
I 52 5/5/06 Lot 12 248 22 1 99 0 5 92%
53 5/5/06 ':Lót8 248 23.0 101.0. . 5. 93% :
1 54'5/5/06 Lot 13 .. 247 24:i. 970 .5 90%
I 4..
55 5/8/06 Lot 9
...•-.,
249 23.8,,:,97.0 5 90%
56 518/06 Lot 6 242 204 100.0 5 92%
57 5/9/06 Lot 10 250 211.2 1000 5-" 93%
I 58 5/9/06 Lot 7 248 198 103.0 5 950io Fail
59 5/11106 Lot 249 236 980 5 91%
I 60 5/11/06 Retest #58 248 24.2 W.0 5 90%
61 5/11/06 Lot 12 248 244 990 5 91%
62 5/11/06 Lot 5 244 24 1 97.0 5 90%
I 63 5/12/06 Lot 246 234 980 5 91%
64 5/12/06 Lot 13 2485 229 1000 5 93%
- . ••- . ..
I 65 5/12/06 Lot 7 249 23 8 98.0'- 5 91%
66 5/15/06 Lot 6 248 25.1 91.0 5 90%
67 5/15/06 Lot 14 - 246 246 980 5 91%
68 5/15/06 Lot 5 247 25;0 97.0 5 90%
69.6/1.6/064.,Lot 4 246 26.3 93.0 5 86% Fail
70 5/16/06 Lot 14 246.5 24.1 97.0 5 90% I 71 5/16/06 Retest #69 246 25 8 97 0 5 900
72 5/16/06 Lot 5 248..23.5'-''98.0 5 91% sm
.• • - ,_•4 I .•
. . .••
.
• . .. • - Job No. 97-7189 • • .
Figure IlIb
pop U • • - . - ..•- • .. -. •-, • .,. ..• . . -
4
- .. • • 4, - . - . • - f I • - • .. . • . ;.. .• .',.,• . . . . • . • •
, •, •• 4_ . -. . . ., ••
4-
-4-
JobNo97-7189
,
p
Figure4- IlIc
I.
3 -
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PROPOSED STRUCTURE TOP OF COMPACTED FILL SLOPE
I (Any loose soils on the slope surface
-
CONCRETE FLOOR SLAB . -
. shall not be considered to provide
O lateral or vertical strength for the
SETBACK •
, footing or for slope stability Needed
5' 1' ------f • / depth of igdedment shall be measured
,,•4 '., . 4' 4 - 4 •V4 q
- -
7. from competent soil.) -
-
- -
•
"'S ' ".
.
COMPACTED FILL SLOPE WITH
MAXIMUM INCLINATION AS'
I 'N PER SOILS REPORT
7 REINFORCEMENT OF .s, • . _-
FOUNDATIONS ANDFLOOR TOTAL DEPTH OF FOOTING MEASURED
I .\ SLABS FOLLOWING THE 1! '. FROM FINISII.SOIL SUB-GRADE
I RECOMMENDATIONS OF THE
ARCHITECT OR STRUCTURAL ENGINEER • Is.. ' COMPACTED FILL --. -
•
I CONCRETE FOUNDATION ,., I 'S -
'
.
.
180 NININIJI OR AS DEEP AS OUTER MOST FAC"5... 5'
REQUIRED FOR LATERAL OF FOOTING ' '5
STABILITY
I
TYPICAL SECTION
(SHOWING PROPOSED FOUNDATION LOCATED WITHIN 5 FEET OF TOP OF SLOPE)
I 18" FOOTING! 5' SETBACK
I TOTAL DEPTH OF FOOTING
1.6:1.0 SLO1E 2.0:1.0 SLOPE
I
- 4
- S - 11
0 5811 4811
1-' 5111!- " 42°
2' - 42" 3611
31 3491 - 3013
4' - 26°
5 18" 18"
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FIGURE NUMBER IV
F - JOB NUMBER 97-7189, -
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5
. -' ii14~-
I 64Ni Ge"otechn'lcal Ex ploration, Inc.
SOIL AND FOUNDATION ENGINEERING'* GROUNDWATER. ENGINEERING GEOLOGY I
I I
08 June, 2006
I
I
: RWR HOMES, INC'Job No: 97-7189
e West Suite 2710 LokerAvenu, 350
Carlsbad, CA 92008
I Attn: Mr. Brendan Farrelly,
/ - -
Subject: Additional Soluble Sulfate-Tests and Expäflsioñ Index
-:Test Results - -
Proposed Emerald Pointe EstatesSubdivisioñ .
APN 212-040-50 -
I Northwest of Cobblestone Drive, East of Laurel Tree Road
Carlsbad, California -
I Dear Mr. Farrelly:
As requested, we have sampled the soils near pad subgrade elevations at the
I subject subdivision to measure soluble sulfate texposure levels, as well as to
measure the expansion Jndex for foundation ernbednert depth and, reinforcing.
I The attached test results indicated that the soluble sulfate values range from 0.142
to 0.231 percent in accordance with California Test Method 417. The reults, per
I -
UBC guidelines, indicate that the soils have a moderate (between 0.10 and 0.20 %)
- to severe (between 0.201 and.2.00 %) sulfate exposure. Therefore, thefôundation
and slabs on-grade (or other, concrete structures, in contact with the soils) should
have a water-cement ratio not exceeding 0.50 for moderate soluble sulfate'
I exposure and 0 45 for severe soluble sulfate content, and/or have a compressive
strength of 4,000 psi for moderate soluble sulfate exposureor 4,500 psi for severe
I sulfate exposure Because the soluble sulfate values went to higher values in our
most recent sampling,.we recommend that, forease of cohstruction, all concrete in
I contact with soil should contain type V cement 4
I,
7420 TRADE STREEr. SAN DIEGO, CA 921210 (858) 549-7222 *.FAX: (858) 549-16D4 S EMAIL qeot66@gei-sd.com
1 H
Proposed Emerald Pointe Estates Job No 97-7189
Carlsbad California. S , . ' . Page 2
I •. . ' -
_ '
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I .Expansion Index Test results yielded values 'ranging from 116 to 165. The - - * .5 . •__.% .average,
5-I
expansion index test result was 133 We recommend that all perimeter foundation
I excavations for slabs on-grade be deepened to at least 30 inches into the ground be
lowest adjacent subgrade, which is Category IV Interior foundations should be
I embedded to 21 inches below pad subgrade elevations Foundations and slabs
should be reinforced as indicated in the project's pot-tensioned slab plans
Subgrade soils should -be'- maintained, with high soil moistüré content' (at least .5 .
I percent' over the optimum) by sprinkling the soil surface at least J. minutes every
other day. Our field representative should verify the depth of embedment of
I foundations and soil moisture adequacy withir 48 hours prior to" concrete
placement
All other recommendations presented in our previous reports on the project remain
I applicable unless superseded in writing by our firm
If you have any questions regarding this letter, please contact our office Reference
to our Job No 97-7189 will help expedite a response to your inquiry.
- S 4
I . ''-
5 . S •, .,
S 'Respectfully submitted,
GEOTECHNICAL EXPLORATION, INC
I p.
- R.C.E.'34422/G.E.2007 S . --# • - -'5 S
Senior Geotechnical Engineer -
4' '5
IL
JP
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