HomeMy WebLinkAbout; Apartment Complex Poinsettia Lane; Soils Report; 1984-05-16,,,- .,.:
SOILS INVESTIGATION
APARTMENT COMPLEX
Between Camino de las Ondas and Poinsettia Lane
Carlsbad, California
PREPARED FOR:
Lincoln Properties
701 rrB" Street, Suite 1300
San Diego, California
PREPARED BY:
Ketchum Engineering
9508 Markwood Drive
Santee, California 92071
.,- Lincoln Properties May 16, 198&
701 "B" Street, Suite 1300
San Diego, California 8430
Report #l
SUBJECT: Preliminary Geotechnical Investigation For Proposed
22 Acre Apartment Complex Between Camino de las
Ondas and Poinsettia Lane, Carlsbad, California.
Gentlemen:
In accordance with your request we have performed an investi-
gation of the soil conditions at the subject site. We are
transmitting herewith a report of this investigation.
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The analysis of our findings is intended to provide the
required information to design the foundation and prepare
the grading plans for the proposed development.
In general, we found the site to be suitable for the proposed
development provided the recommendations contained in the body
of this report are followed. On site conditions which will
require special design considerations will include alluvial
removal and recompaction from the swales and moderately ex-
pansive soils.
If you have any questions after reviewing our report, please
do not hesitate to contact this office. This opportunity
to be of service is sincerely appreciated.
Respectfully Submitted,
E.N.Ketchum, R.C.E. 26267
5)Submitted
2)Eugene Roach & Associates
KETCHUu ENGINEERING
9508 MARKwoOn DR., SANTEE, CA., 92071. OIS-440-3929
TABLE OF CONTENTS
Page Introduction and Project Description .......... 1
Project Scope ..................... 2
Field Explorations ................... 3
Laboratory Testing ................... 3
Findings ........................ .
Site Description. ................. 5
Soil Conditions .................. 6
Groundwater .................... 7
Conclusions. ...................... 8
Recommendations. .................... 9
Site Preparation. ................. 9
Demolitions, Clearing and Grubbing ...... 9
General. ................... 9
Selective Grading For Potentially
Expansive Soils .............. 9
Transition Lots. .............. '.lO
Areas To Be Paved. ............. .lO
Moisture Content For Fill Soils. ...... .ll
Subdrains. ................. .11
Select Imported Fill Material. ........ .ll
Earthwork. ................. .ll
Slope Stability ................. .12
General. .................. .12
Temporary Slope Stability. ......... .12
Foundations ................... .13
General. .................. .13
Alternative I ............. .13
Alternative II. ............ .13
Alternative III ............ .15
Settlement Characteristics. ...... .16
Earth Retaining Structures. ........... .16
General. .................. .16
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Pa e Backfill .................. 1E
Allowable Soil Bearing Pressure. ...... .16
Ultimate Passive Pressure. ......... .16
Ultimate Active Pressure ........... .17
Factor Of Safety .............. .17
Limitations. ..................... .18
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ATTACHMENTS
PLATES
Plate 1 Site Plan
Plate 2 Subsurface Exploration Legend
Plates 3-13 Subsurface Exploration Logs
Plate 14 Direct Shear Test Results
Plate 15 Grain Size Distribution
Plate 16 Typical Canyon Subdrain
Plate 17 Detail-Weakened Plane Joint
APPENDIX
Recommended Grading Specifications - General Provisions
and Special Provisions
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GEOTECHNICAL INVESTIGATION
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22 ACRE APARTMENT COMPLEX
BETWEEN CAMINO DE LAS ONDAS AND POINSETTIA LANE
CARLSBAD. CALIFORNIA
INTRODUCTION AND PROJECT DESCRIPTION
This report presents the results of our geotechnical in-
vestigation for the proposed 22 acre site located between
Camino de las Ondas and Poinsettia Lane. The site location
is shown on the Vicinity Map provided as Figure 1.
It is our understanding that the site is to be developed
by the construction of one and two story. wood frame stucco
exterior structures with slab-on-grade construction. It
is further understood that because of the rolling hills
type site, a moderate amount of grading is anticipated.
To assist in the preparation of this report, we were pro-
vided with a topography map. Site plans have not been
developed as of this writing. The site configuration
and locations of our subsurface explorations are shown
on the site plan on Plate Number 1 of this report.
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KETCHUM ENGINEERING
9508 MARKWOno DR., SANTEE. CA., 92071, S19-44D-3929
FIGURE 1
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I som Cm‘Ss, m,m~
.-------+------~
‘..*.++-l-.-.-. -.-.I _
UGOON 1 1
0 --w \. Yt -+.e.+., I
KETCHUM ENGINEERING
9508 MAAKWOlIo OR,, SANTEE, CA., 92071, 019-440-3929
Page 2
PROJECT SCOPE
This investigation consisted of: surface reconnaissance;
subsurface explorations: obtaining representative dis-
turbed and undisturbed samples; laboratory testing;
analysis of the field and laboratory data: research of
available geological literature pertaining to the site;
and preparation of this report. Specifically, the intent
of this study is to:
a) Explore the subsurface conditions to the depths
influenced by the proposed construction.
b) Evaluate, by laboratory tests, the pertinent
engineering properties of the various strata
which will influence the development, including
their bearing capacities, expansive characteristics
and settlement potential.
cl Define the general geology at the site including
possible geologic hazards which could have an
effect on the site development.
d) Develop soil engineering criteria for site grad-
ing and provide design information regarding
the stability of cut and fill slopes.
e) Determine potential construction difficulties
and provide recommendations concerning these
problems.
f) Recommend an appropriate foundation system for
the type of structures anticipated and develop
soil engineering design criteria for the rec-
ommended foundation design.
KETCHUrn ENGINEERING
9508 MARKWOCI~ DR,, SAQNTEE, CA., 92071, fils-440-3929
Page 3
FIELD EXPLORATIONS
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Eleven subsurface explorations were made at the locations
indicated on the attached Plate Number 1 on April 27, 1984.
These explorations consisted of backhoe trenches. The
field work was conducted under the observation of our
engineering personnel.
The explorations were carefully logged when made. These
logs are presented on the following Plate Numbers 3 through
13. The soils are described in accordance with the Uni-
fied Soils Classification System as illustrated on the
attached simplified chart. In addition, a verbal textural
description, the wet color, the apparent moisture and the
density or consistency are given as either very loose,
loose, medium dense, dense or very dense. The consis-
tency of silts or clays are given as either very soft,
soft, medium stiff, stiff, very stiff, or hard.
Disturbed and undisturbed samples of typical and rep-
resentative soils were obtained and returned to the
laboratory for testing.
LABORATORY TESTING
Laboratory tests were performed in accordance with the
generally accepted American Society for Testing and
Materials (S.S.T.M.) test methods or suggested pro-
cedures. A brief description of the tests performed
is presented below:
a) Moisture-Density: Field moisture content and
dry density were determined for representative
samples obtained. This information was an aid
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KETCHUM ENGINEERING
9508 MARKWO00 DR., SANTEE, CA., 92071, ~19-443-3929
Page 4
to classification and permitted recognition
of variations in material consistency with depth.
The dry unit weight is determined in pounds per
cubic foot, and the field moisture content is
determined as a percentage of the soil's dry
weight. The results are summarized in the trench
logs.
b) Classification: Field classifications were ver-
ified in the laboratory by visual examination.
The final soil classifications are in accordance
with the Unified Soil Classification System.
cl Direct Shear Tests: Direct shear tests were per-
formed to determine the failure envelope based
on yield shear strength. The shear box was de-
signed to accomodate a sample having diameters
of 2.375 inches or 2.50 inches and a height of
1.0 inch. Samples were tested at different
vertical loads and at saturated moisture content.
The shear stress was applied at a constant rate
of strain of approximately 0.05 inches per min-
ute. The results of these tests are presented
on attached Plate Number 14.
d) Compaction Test: The maximum dry density and
optimum moisture content of typical soils were
determined in the laboratory in accordance with
A.S.T.M. Standard Test D-1557-70, Method A. The
results of these tests are presented on the at-
tached Plate Number 14.
KETCHUM ENGINEERING
9508 MARKWCCC CR., SANTEE. CA.. 92071~ 019-440-3929
Page 5
e) Expansion Index: The expansion index of clayey
soils was determined in accordance with U.B.C.
Standard Number 29-2. The typical clayey silty
sandstones were determined to have an expansion
index of 13 which would be classified as having
a low potential for expansion. The clayey soils
found in Trench T-l+ @ 7' would be classified as
having a medium expansive potential with an E.I.
of 80. These clayey materials would, however, have
a high expansive potential in their present un-
disturbed state.
f) Grain Size Distribution: The grain size dis-
tribution was determined for representative sam-
ples of the native soils in accordance with
A.S.T.M. Standard Test D-422. The results of
these tests are presented on Plate Number 15.
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FINDINGS
SITE DESCRIPTION:
The 22 acre, undeveloped site, is an irregular parcel of land
that is bounded on the north by Camino de las Ondas, on the
east and west by graded residential property, and on the south
by Poinsettia Lane. Buttercup Road traverses the southern
portions of the property. This newly constructed road has a
box culvert running north to south that will drain the entire
site. The rest of the property is drained by sheet flow to
the natural and man-made swale that traverses the parcel
along the western side from the north to the south. A de-
silting basin exists on the north side of Buttercup Road.
There is a 2:l engineered fill slope on this parcel that has
been constructed all along the western property line by the
adjacent development. On-site vegetation consists of the
natural grasses and shrubs.
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KETCHUM ENGINEERING
9508 MARKWCCo CR., SANTEE. CA., 92071 n1s-44o-3s2s
Page 6
I- I SOIL CONDITIONS:
In general, this site is underlain by Pleistocene sed-
iments or moderately cemented sandstones which consist
of brown to reddish brown, medium dense to dense silty and
clayey sands. The topsoils consisted of a loose to med-
ium dense, tan to reddish brown silty sand, that ranged
in thickness from about 2.5, 0.5 and 2 feet in trenches
T-l, T-4, and T-7. The more recent alluvial deposits in
the drainage swales consist of loose to medium dense silty
sands and dark brown soft to medium stiff sandy silts.
These alluvial soils were found to be about 6, 1.5, and
2 feet in thickness for trenches T-2, T-3, and T-11 re-
spectively for the northerly east-west swale. For the
southerly northeast to southwest swale, the alluvial mater-
ials were determined to be about 10 feet in thickness for
trench T-6. In trench T-5, our backhoe trench was ex-
tended to its maximum limit of 16 feet below the surface
but we did not encounter natural materials. It is an-
ticipated that competent natural soils would .be encoun-
tered at depths on the order of 18 to 20 feet as indicated
by the very wet soils found at a depth of about 15 feet.
It is common for water to be perched or present in an
alluvial swale just above dense natural materials.
Although no backhoe trenches were extended to the small
parcel between Buttercup and Poinsettia Lane, the soils
are anticipated to be comprised of the natural, reddish
brown, moderately indurated sandstones, that were found
on the majority of the remainder of the site.
The desilting basin just north of Buttercup Road appears
to have had all the alluvial soils removed from the
drainage swale and replaced by a compacted engineered
KKTCHUM ENGINEERING
9508 MARKWQOCI OR., SANTEE, CA., 92071, RIS-440-392s
Page 7
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fill. This procedure was probably done at the time
Buttercup Road was constructed.
There is a highly expansive clay layer that is about 3
feet in thickness that was found in trench T-l, at a depth
of about 6.5 feet.
GROUNDWATER:
Although no standing groundwater table was encountered
during our subsurface exploration, we did find very wet
soils at the bottom of the trench T-5. It is anticipated
that groundwater conditions will be encountered during the
removal of the alluvial materials in this swale. No other
groundwater conditions were encountered in any of our other
subsurface explorations and we do not anticipate any major
groundwater related problems, either during or after con-
struction. However, it should be recognised that minor
groundwater seepage problems may occur after development
of a site, even where none were present before development.
These are usually minor phenomena and are often the result
of an alteration of the permeability characteristics of
the soil, an alteration in drainage patterns and an in-
crease in irrigation water. Based on the permeability
characteristics of the soil and the anticipated usage of
the development, it is our opinion that any seepage prob-
lems which may occur will be minor in extent. It is further
our opinion that these problems can be most effectively
corrected on an individual basis if and when they develop.
KETCHUM ENGINEERlNG
9508 MARKWCCC OR., SANTEE, CA., 92071. RIS-440-3929
Page 8
CONCLUSIONS
Based on the findings of this study, we conclude that,
with respect to geotechnical aspects, the subject site is
suitable for the proposed project provided the recommenda-
tions contained in this report are fully complied with.
The topsoils and alluvial soils in the on-site drainage
swales should be removed and replaced as an engineered
fill prior to receiving any fill and/or structural loads.
This procedure is recommended because these materials were
determined to be loose in consistency, porous in nature
and subject to excessive consolidation if loaded and al-
lowed to come in contact with appreciable amounts of water.
Because some of the soils within this formation were
determined to have a medium expansive potential, some
special earthwork procedures and foundation design re-
quirements will be recommended.
We further suggest that any highly expansive, clayey soils
encountered during earthwork procedures be placed at least
2.5 feet below proposed finish grade.
If buildings or structural loads are to be placed over the
existing desilting basin, then the compaction report (if
it exists) should be located and checked by this office
for proper natural ground preparation and test results
prior to earthwork procedure. If no compaction report
is available for this area, then the soils beneath these
proposed structures should be removed and replaced as an
engineered fill.
KETCHUM ENGINEERING
9508 MARKWCX!Zl~ DR., SAN~TES, CA., 92071~ SlS-440-3929
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RECOMMENDATIONS
SITE PREPARATION
r-
DEMOLITIONS, CLEARING AND GRUBBING: During site prepara-
tion all debris and deleterious materials derived from
demolition clearing and grubbing operations should be
legally disposed of off-site. Any existing utilities that
will not be utilized should be removed and properly capped
off at the property line. The removal of trees should in-
clude the removal of their rootballs. The depressions
resulting from the above operation should be backfilled
with soil that has been compacted to at least 90% relative
compaction.
GENERAL: Beneath all areas to receive structural building
loads, fill soils, or asphalt pavements, we recommend that
the loose top soils and alluvial materials be removed to
firm natural ground and stockpiled for future use. Firm
natural ground is defined as soil which possesses an in-
place density equal to or greater than 85% of its maximum
dry density. The soils at the bottom of the excavation should
be scarified to a minimum depth of 6 inches, watered if
necessary, and compacted to at least 90% relative com-
paction. The stockpiled soils may then be replaced and
compacted in 6 to 8 inch lifts to at least 90% relative
compaction. The above recommendations should include the
area within 5 feet beyond the building perimeters.
SELECTIVE GRADING FOR POTENTIALLY EXPANSIVE SOILS: Al-
though the typical clayey silty sandstones underlying most
of this site were determined to have a low potential for
expansion, there,are some moderately to highly expansive
soils within this sedimentary formation. Therefore, it
KETCHUM ENGINEERING
9508 MARKWWQlI DR., SANTEE, CA., 92071, GIS-44Q-3923
Page 10
is recommended that wherever expansive soil is used in
fill, it be placed a minimum of 2.5 feet below finish grade
and wherever it occurs within 2.5 feet of finished cut
grade, it be removed and be replaced with nonexpansive
soils. The lateral extent of this recommendation shall
apply to the area within a perimeter of ten feet outside
of the proposed structure. Conventional footing designs
may then be used for the proposed structure.
If it is found infeasible to cap all of the building pads
with nonexpansive soils as recommended above, then the
degree of expans.iveness of the soils on each lot contain-
ing expansive soils in the upper 2.5 feet will have to be
determined at the completion of grading in order that
special foundation recommendations can be developed to
minimize potential damage resulting from expansive soils.
Please refer to the 'foundation recommendations' section
of this report for design suggestions.
TRANSITION LOTS: Foundations supported partially on cut
and partially on fill are not recommended. The tendency
of cut and fill soils to compress differently will prob-
ably result in unequal structural support and consequen-
tial cracking. Therefore, in transition areas, we recommend
that the entire area be undercut and be replaced with
soils compacted to a minimum of 90%. The undercutting
should be carried to a depth of 1 foot below the base of
the deepest footing.
AREAS TO BE PAVED: The subgrade soils beneath all areas
to be paved should be densified to at least 90% to a depth
of at least 12 inches.
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KETCHUM ENQINEKRING
9508 MARKWOCIC CR., SANTEE, CA., 92071~ SIS-440-392s
Page 11
MOISTURE CONTENT FOR FILL SOILS: All fill soils should
be placed with moisture contents of at least 3% over op-
timum moisture content.
SUBDRAINS: We recommend that a 4 inch perforated drain
line,surrounded with at least 3 cubic feet of crushed
rock per lineal foot of line, be placed in the bottom of
channels to attempt to alleviate any subsurface seepage
that could collect in these areas from seeps and/or irri-
gation after development. Please refer to Plate Number 16.
This recommendation is subject to review once the grading
plans have been completed and reviewed by this office.
SELECT IMPORTED FILL MATERIAL: Imported fill material
should consist of granular, nonexpansive soil that con-
tains no organic or deleterious materials. It shall have
sufficient cohesion to hold a vertical or near vertical
cut for footing excavations. It shall have at least 85%
of the material passing the Number 4 sieve with no rocks
or chunks larger than 14 inches. The import fill should
be approved by our office prior to it being delivered to
the site.
EARTHWORK: All earthwork and grading contemplated for
site preparation should be accomplished in accordance with
the attached Recommended Grading Specifications and
Special Provisions. All special site preparation recom-
mendations presented in the sections above will supercede
those in the Standard Recommended Grading Specifications.
All embankments, structural fill and fill should be com-
pacted to a minimum of 90%. Utility trench backfill with-
in 5 feet of the proposed structures and beneath asphalt
pavements should be compacted to a minimum of 90% of its
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KETCHUM ENGINEERING
9508 MARKWOClo OR.. SANTEE, CA., 92071. SIS-440-3929
Page 12
maximum dry density. The maximum dry density of each
soil type should be determined in accordance with A.S.T.M.
Test Method 1557-702, Method A or C.
SLOPE STABILITY:
GENERAL: The cut and fill slopes constructed from the
native on-site materials will be stable with relation to
deep-seated failures if constructed at, or flatter than,
the following recommended slope ratios expressed in hor-
izontal to vertical units for the indicated heights:
Cut Slopes to 50 Feet in Height: 2:l
Fill Slopes to 40 Feet in Height: 2:l
The above. maximum heights were determined by using a fac-
tor of safety of 1.5.
It is also recommended that footings not be founded nearer
than five feet measured horizontally inward from the face
of the slopes. Slopes should be planted with erosion
resisting plants and natural drainage should be directed
away from the top of all slopes.
TEMPORARY SLOPE STABILITY: The following table presents
recommendations relative to temporary construction ex-
cavations. These slopes should be relatively stable
against deep-seated slope failures but nay experience
localized sloughing.
Slope Ratio Maximum Height of Temporary
(Horizontal to Vertical) Excavation (Feet)
0.75 : 1 15
Vertical 5
KETCHUrn ENGINEERING
9508 MARKWOCJII OR., SANNTE, CA., 92071~ QIS-aon-
Page 13
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It should be the contractor's responsibility to provide
safe support for the excavation. No heavy equipment should
be allowed adjacent to the top of the temporary cuts.
FOUNDATIONS
GENERAL: In consideration that both nonexpansive soils and
expansive soils exist on-site and since it is not known
at this time if all building pads will be capped with non-
expansive soils, the following three alternative recommen-
dations are submitted:
Alternative I: Construction on Nonexpansive Soils: (E.I.
less than 20). Structures founded on lots containing
nonexpansive soils within 2.5 feet of finished grade may
be constructed using conventional spread footings. Spread
footings should have a minimum width of 12 inches and should
be founded at least 12 inches below adjacent finished grade
for one and two story structures. Footings on nonexpansive
soils may be designed for an allowable soil bearing pres-
sure of 2500 psf. These footings should be reinforced with
one No. & bar top and bottom.
Alternative II: Construction On Moderately Expansive
Soils: (E.I. less than 90%). The following recommenda-
tions are provided for construction on the expansive
soils.
a) Conventional spread footings should be founded
a minimum of 12 and 18 inches below the lowest
adjacent finish grade for one and two story
structures, and have a minimum width of 12 and
15 inches respectively.
KETCHUM ENGINEERING
9508 MARK’JJOCl0 CR., SAN~TEE. CA., 92071. Fjis-440-3929
Page 14
b) All footings may be designed for an allowable
soil bearing pressure of 2000 psf.
c) Both exterior and interior continuous footings
should be reinforced with one #4 bar positioned
near the bottom of the footings and one #4 bar
positioned near the top of the footing.
d) Interior slabs for living areas should be a
minimum of 3h inches thick, underlain by a 4
inch blanket of clean sand or crushed rock,
reinforced with 6~tx6n-10/10 welded wire mesh
and completely surrounded with a continuous
footing. Interior slabs not used for living
areas such as garages need not be underlain by
sand or rock.
e) Exterior slabs should be a minimum of 34 inches
thick. Walks or slabs five feet in width need
not be reinforced. Those exceeding. five feet
in width should be reinforced with 6"x6"-lo/10
welded wire mesh.
f) Surface drainage should be directed away from
the proposed foundation. Over-irrigation of
areas adjacent to foundations and slabs should
be avoided.
g) Adjacent footings founded at different bearing
levels should be so located that the slope from
bearing level to bearing level is flatter than
one horizontal to one vertical.
KETCHUM ENGINEERING
9508 MARKWOCID OR,, SANTSE, CA,, S207q. Q19-440-3929
Page 15
h) Prior to pouring concrete, the foundation ex-
cavations should be inspected by a representative
of this office to determine if the recommenda-
tions in this report have been followed.
Alternative III: Construction On Highly Expansive Soils:
(E.I. greater than 90%) The following recommendations
are provided for construction on the expansive soils.
a) All footings should be founded a minimum of 24
inches below adjacent finish grade and may be
designed for an allowable soil bearing pressure
of 1800 psf. Footings should have a minimum
width or diameter of 12 inches.
b) Both exterior and interior continuous footings
should be reinforced with two Number 4 bars
positioned 3 inches above the bottom of the
footings and two Number 4 bars positioned 4
inches below finish floor.
cl Weakened plane joints for exterior slabs should
be provided for any slab greater than ten feet in
width. Any slabs between 5 and 10 feet should
be provided with a longitudinal weakened plane
joint at its center line. Slabs exceeding 10
feet in width should be provided with a weak-
ened plane joint located 3 feet inside the ex-
terior perimeter. Both transverse and long-
itudinal weakened plane joints should be con-
structed. Please refer to Plate Number 17.
Items "d" through "h" of Alternative II are also applicable.
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KETCHUM ENGINEERlNG
9508 MARKWCICC CR., SANTEE. CA., 92071. GIS-440-392s
Page 16
Settlement Characteristics: The anticipated total and/or
differential settlements for the proposed structure may
be considered to be within tolerable limits provided the
recommendations presented in this report are followed.
EARTH RETAINING STRUCTURES:
GENERAL: Retaining structures may be planned for this
project. The following criteria may be used for design
purposes.
BACKFILL: All backfill soils should be compacted to at
least 90% relative compaction. Expansive or clayey soils
should not be used for backfill material within a distance
of 5 feet from the back of the wall. The retaining struc-
ture should not be backfilled until the materials in the
wall have reached an adequate strength. -.
ALLOWABLE SOIL BEARING PRESSURE: The foundation for the
proposed retaining structures should consist of spread
footings founded in the firm native soils or compacted
fill. Firm natural ground is defined as soil having an
in-situ density of at least 85% of its maximum dry density.
Footings may be designed for an allowable bearing pressure
of 2000 psf.
ULTIMATE PASSIVE PRESSURE: The passive pressure for pre-
vailing soil conditions may be considered to be 290 pounds
per square foot per foot of depth. This pressure may be
increased one-third for seismic loading. The coefficient
of friction for concrete to soil nay be assumed to be
.31 for the resistance to lateral movement. When combining
frictional and passive resistance, the latter should be
reduced by one-third.
KETCHUM ENGINEERING
9508 MARKWOCJD OR.. SANTEE, CA., 32071. Rls-440-392s
Page 17
ULTIMATE ACTIVE PRESSURE: The ultimate soil pressure for
the design of earth retaining structures with level back-
fills may be assumed to be equivalent to the pressure of
a fluid weighing 41 pounds per cubic foot for walls free
to yield at the top (unrestrained walls). For walls with
a 2:l backfill slope we recommend an equivalent fluid
pressure equal to 47 pcf. For earth retaining structures
that are fixed at the top (restrained walls), an ultimate
equivalent fluid pressure of 65 pounds per cubic foot may
be used for a design parameter. These pressures do not
consider any surcharge loading (other than the sloping
backfill). If any surcharge loadings are anticipated,
this office should be contacted for the necessary increase
in soil pressure. All earth retaining structures should
have adequate weep holes or a subdrain system to prevent
the buildup of hydrostatic pressure behind the wall.
FACTOR OF SAFETY: The above values, with the exception
of the allowable soil bearing pressure, do not include
a factor of safety. Appropriate factors of safety should
be incorporated into the design of all earth retaining
structures to reduce the possibility of over turning and
sliding.
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K.E T C H U M ENGINEERING
9508 MARKWCOC CR.. SANNTEE, CA.. 92071. SIS-440-3323
Page ia
LIMITATIONS
REVIEW, OBSERVATION AND TESTING
The recommendations presented in this report are con-
tingent upon our review of final plans and specifica-
tions. The soil engineer and engineering geologist
should review and verify the compliance of the final
grading plan with this report.
It is recommended that a qualified soils engineering
firm be retained to provide continuous soil engineering
services during the earthwork operations. This is to
observe compliance with the design concepts, specifi-
cations or recommendations and to allow design changes
in the event that subsurface conditions differ from
those anticipated prior to start of construction.
UNIFORMITY OF CONDITIONS
The recommendations and opinions expressed in this re-
port reflect our best estimate of the project require-
ments based on an evaluation of the subsurface soil
conditions encountered at the subsurface exploration
locations and the assumption that the soil conditions
do not deviate appreciably from those encountered. It
should be recognised that the performance of the found-
ations and/or cut and fill slopes may be influenced
by undisclosed or unforeseen variations in the soil
conditions that may occur in the intermediate and un-
explored areas. Any unusual conditions not covered
in this report that may be encountered during site
development should be brought to the attention of the
soils engineer so that he may make modifications if necessary.
KETCHUM ENGINEERING
9503 MARKWOOO OR., SANTEE, CA., 92071 613-aaa-392s
CHANGE IN SCOPE
Page 19
This office should be advised of any changes in the pro-
ject scope or proposed site grading so that it may be
determined if the recommendations contained herein are
appropriate. This should be verified in writing or
modified by a written addendum.
TIME LIMITATIONS
The findings of this report are valid as of this date.
Changes in the condition of a property can, however,
occur with the passage of time, whether they be due to
natural processes or the work of man on this or adjacent
properties. In addition, changes in the State-of-the-Art
and/or Government Codes may occur. Due to such changes,
the findings of this report may be invalidated wholly
or in part by changes beyond our control. Therefore,
this report should not be relied upon after a period of
two years without a review by us verifying the suitabil-
ity, the conclusions, and recommendations.
PROFESSIONAL STANDARD
In the performance of our professional services, we
comply with that level of care and skill ordinarily
exercised by members of our profession currently prac-
ticing under similar conditions and in the same local-
ity. The client recognizes that subsurface conditions
may vary from those encountered at the locations where
our borings, surveys, and explorations are made, and
that our data, interpretations. and recommendations are
based solely on the information obtained by us. We
will be responsible for those data, interpretations,
KETCHUM ENGINEERING
9500 MAAKWOOD OR., SAiNTEE, CA., 92071 61S-aaa-3929
Page 20
and recommendations, but shall not be responsible for
the interpretations by others of the information devel-
oped. Our services consist of professional consultation
and observation only, and no warranty of any kind what-
soever, express or implied, is made or intended in con-
nection with the work performed or to be performed by
us1 or by our proposal for consulting or other services,
or by our furnishing of oral or written reports or find-
ings.
.-
CLIENT'S RESPONSIBILITY
It is the responsibility of the owners, or their rep-
resentative to ensure that the information and recom-
mendations contained herein are brought to the attention
of the engineer and architect for the project and incor-
porated into the project's plans and specifications.
It is further their responsibility to take the necessary
measures to e.nsure that the contractor and his subcon-
tractors carry out such recommendations during con-
struction.
_-
KETCHUM ENGINEERING
9508 MARKWCCD CR,, SANTEE, CA,, 92071 61S-aaa-3923
SUBSURFACE EXPLORATION LEGENO
uws.co MP.# wsIr*cmI~ aAm
50u. oescsrPrr~ !ac- Sy?cBQC TyPLmL WACS
1. coAns* aAIMD. aNa=. than h*lr ot mt*ria1 ir m than LTo. 100 riwe rlr*.
- CLEAN GIZIMLS GT ~.I1 gnd.d grav*1r. gravel-
MOZ. than halt of SalId q ixtur.,, litth *Iz ILO
eolna tacticn is teas.
1*rg.r than LTO. 4 OP PImay graded grav*1r. gnv*l
r1.v. sic?. hue #and slxar*r. 1iet1a o+ no
rm.11.r than 3'. iiNS. Mvu.S WITn rIm.9 GM Silty grav.1,. p.xrly gradad (Apprasi*l* aowunt gr~“.l-,and-*ilt mixeur.,. or rima .u: c1ay.y grw.1,. pQor1y przKl.d grrv*1-*and. clay mlxrurea .
wehan halt ot- SAN0S SW we11 glad.d rand. pra".lly s*nds, tiCtl* or no finer. c0a.n. trueion is SP Poorly *zad.d rh-as.grav*llY rma11.r than NO. 4 sands. lit+l* or no tin*,. Sl.". *iz.. SWDS WPm FINES SM Silty sand,. poc~ly g+ad.d (Appr~eiabh mount sand and rile mixtures. ot !Zinerl SC Clayey randr. poorly graded ran* a"* clay mixtures.
Il. PRCS GWNCD. nor. ehrn h.1L af m.t.rial is u than HO. 200 slwe liza. SILTS Am CLAYS .* Inorganic rilcr and v*ry tin. sands, Cock t1our. sandy silt ok- clay.y-*ile-smd mix+ur~l with rlipht plasc- icity Liquid Limit a Incrqanic clays ot led to 1.r. than 50 m.dium pl*srisiey.~ra”.lly c1*ys. randy elays.siky clay‘, 1.m clay,. Q‘ Orqanic riLcr and organic silty clays ot 10.1 plarticicy sn.?s m CLAYS m Inorganic silts. micaceous as dtatomac.ous tine sandy or riley soils, l larric silt,. Liquid Limit CH Inorqanic clays ot high gr.a+.r ehln 50 plasticity, tat clays. OH orqmic clays ot medium co high plarcicity.
irI0ta.Y QRGiLYIC SOTIS PT p.*c and 0el.r hiqhly organic rolls.
$ - Water level at time of excavation or as indicated
us - Undisturbed, driven ring sample or tube sample
CK - Undisturbed ci~nk sample
as - Bulk sample
KETCHUM ENGINEERING LINCOLN APARTMENTS
1
By ENK m7z 5/15/a&
Jo8 *. 8430 Plate #2 --. . ._~~. ~. .-.-.-.. .-. -. .-... -.- .~ - _. .-A ___,-._.-
z
ii
2 ; TRENCH NUMBER T-l ; ; g 4 : ; ,z z f z = < uf 0
Au- := ww;; a:2 : z+ 2 E
Y sy ELEVATION :!f? Ul= I- 2
:
c 0
0 *nv, 2;; z 0 IJ -P i?;
: :I”
:z
r= O,=a i’ : :, E” z :z
;
0
DESCRIPTION 0 0
SM Tan silty sand Dry Loose
(top soil)
_ Bk Med; Dense , -
Ck
I - SM Tan to brown silty Humid Dense sandstone
, -
, -
SI$ Dark greenish gray Moist Med. brown clayey and - Dense- silty sandstone Dense
BOTTOM
-
-
SUBSURFACE EXPLORATION LOG
KETCHUM ENGINZERING LOGGED BY: ENK DATE LOGGED: 27181,
JO8 NUMBER: 8~30 Plate #3
5 ;i 0” 2 TRENCH NUMBER T-2 sg +;* : us ; -: = 2” *rt u 0 :: Luym Gi : ;E 2 c G ELEVATION P$Z Y ij l * ;s
: a. *o;;. 25 2;;: 2 “-E 2:
i r: ;=a :* ;;
: :, <2
go z =0 ; OESCR.lPTlON s 0
SM Tan-brown silty sand Dry Loose (alluvium) l-
?- _ CK Humid Loose-
3 Med. - Dense Moist
1-
5 -- Very
_ CK Loose 96.9 3.7 .
5
_ CK SM/ Red brown clayey and
-
Humid- Med. SC 97.6 12.5 . silty sandstone ?- Dense- (slightly weathered) Dense -
3-
-
)
BOTTOM
SUgSURFACE EXPLORATION LOG
KETCHUM ENGINEERING LOGGED BY: ENK DATE LOGGED: L/27/8/.
JOB NUMBER: 8430 Plate #4
:, 2
: ; TRENCH NUMBER T-3 ; ; ; $ : = Yij z -: 2 4 w 0
:= ww;; ;i 2 Au- :+ ?F
g ,L ELEVATION LL;z
Y *In s= c 2 2; : “zj : 25 2;: “i fn u
2 <2 :2&x 5; ;g
:, : E” 5 20
0
=0
DESCRIPTION 0 0
SM ~~~~~,~~~~;,~;~~~ sand Dry Loose tc Med. Dense
) - SM Dark brown silty sand Moist Med. (weathered sandstone) Dense
_ CK 105.6 13.4 -
BOTTOM
7
j
SUBSURFACE EXPLORATION LOG ~
KETCHUM,ENGINEERING LOGGED BY: ENK DATE LOGGED: 4,27,8;
JOB NUMBER: 8130 Plate #5
0’ ii z! ; TRENCH NUMBER T-& 2 ; ,t* z uz z f z < trc w 0
:: ;j = 22 vl~ol PC+= 5+ 2: I y ou ELEVATION tw := c 2 c 0 2
: 2 “cj ,‘,x 0 0 v) w its -0 2:
:o’g 5;
: :, <I := : s s 0 0 0
u DESCRIPTION 0 0 0
- SM 7;: k;;; silty sand Dry Loose
l- CK ' P
SM Tan silty sandstone Humid Dense slight clay binder 2- -
3- . .
4- CK -
5- -
-
6- v
7- CL Olive green sandy clay Damp Very 96.1 la.8 _
BG Stiff
a-
3-
3- Increased sand content
L
BOTTOM
I
SUBSURFACE EXPLORATION LOG
KETCRUM,ENCINEERING LOGGED BY: ENK DATE LOGGED: 27/aL
JOB HUYEER: a43o Plate #6
z E w 0 2;
5: tag
=0 0
,
I
, ! ; ! , t
i
lRENCH NUMBER T-5
ZLEVATION
1’
2'
3’
5’
5.
?-
3-
?-
I-
t-
s-
I-
j-
i-
t 3M Light brown-red brown silty sand (alluvium) Dry Loose
-B
IL
IL S
Dark brown sandy silt (alluvium) Humid Soft
Silt, clay and sand Med. mixture Stiff 11.5 .08.6
.X+.2 14.2
-
IL Dark brown silt (alluvium) Moist
Damp
Damp
weL
Med. Stiff
;M M: Red brown silty sand (alluvium) Loose- Med. Dense
s: Red brown slightly silty sand (alluvium) 1 Loose- Ied.Dens -L
KETCHUM,ENGINEERING LOGGED BY: ENK DATE LOGGED: 4127184
JOE NUYBER: 8430 Plate #?
,,-
:, z : c 0 : > ; TRENCH NUMBER ~4 *a :
z *,= i”,
Z?
zzt - uz 5
; y s c ELEVATION ;K$ : l” 2
‘,r z 2,;
W= 5+ 2
: ; “Z 0 0
: 2: 2=a -Pi $i
: ;: Z” z 0’:
3 0
2;
; 0 =0
DESCRIPTION 0 0
SM Tan silty sand Dry Loose (alluvium) l-
2 ML Dark brown sandy silt Moist Soft (alluvium)
3-
/+ CK SM ~;~l~fp;;,silty sand Damp Loose
5- Wet -
5- -
7-
3-
)-
1 SM/ Dark red brown clayey Damp Med. SC silty sand (weathered Dense sandstone)
, nZi3e- CK VeryDense
BOTTOM
SUBSURFACE EXPLORATION LOG
KETCHUM ENGINEERING LOGGED BY: ENK DATE LOGGED: 2?/8L
JOE NUMBER: 8430 Plate #S
,-
,-
3’
:-
j-
-
;-
?-
3’
?-
7-
-
G
rRENCH NUMBER T-.,
ELEVATION
OESCAIPTION
Red brown silty clayey sand
Red brown silty sand- stone with slight clay binder
BOTTOM
Dry
Humid
Loose- Med. Dense
Med. Dense Dense
SUBSURFACE EXPLORATION LOG
KETCHUM,ENGINEERING LOGGED BY: ENK DATE LOGGED: L/27laL
JOE NUlA8ER: a430 Plate #9 1
: z
z! p TRENCH NUMBER T-8 c Y ; $ = E uz 3 7 - t < z= w 0 = -ro_ w;j
:E : :* ? c 0’ Y ELEVATION : !5 SEW ;; ;: 2:
0 “&. 1L -
i 4 0 2”O -0
Y l s 5; ii
o ITi z <Z” z = 0
0 =0
OESCR~IPTION 0 0
SM Red brown silty sand Humid Me~d.Densc (fill) l-
2-
3-
4-
5-
6- SM Humid Loose- hf:lyrown,silty sand Med. Dense
7-
a- -
CK -
9 SM Red brown silty sand- Humid Med. stone o- Dense
( Natural)
l- BOTTOM
SUBSURFACE EXPLORATION LOG
KETCHLJM,ENGINEERING LOGGED BY: ENK DATE LOGGED: L,27,a4
JOE NUMBER: a4~o Plate #lO
,-
L -
m
> -
3 -
m
1-
m
j -
s
;-
I -
) -
l-
)-
-
!-
3
1
-
- -
TRENCH NUMBER
ELEVATION
OESCRlPTlON
Red brown silty sa
(fill)
Tan
Caving
BOTTOM
Moist Med. Dense
Wet
SUBSURFACE EXPLORATION LOG
KETCHUM.ENGINEERING LOGGED BY: ENK DATE LOGGED: 4,27/a4
JOB NUMBER: a43o Plate #ll I
,-
2 z : T 5 TRENCH NUMBER T-10 & 2 s
= = 20
5 4 : $ ,w;; wz w 0
z c ELEVATION z= IL;2 z- 5+ ? f I ii l uI I- f
k ; “zj :s 2;; :; y)Y
:=a -0 $I:
: :, 2 l 3
so
2 0’;
3 0
i$
0 0 =0
OESCR~IPTION 0 u
SM/ Light brown silty sand Dry Loose ML and silt L-- (alluvium)
SM/ Black clayey and silty Humid 2- SC sand and sandy clay Very
iz;i;;z&;f) (weathered Stiff
3
SM Tan-red brown silty Moist Dense
I- sandstone
S- BOTTOM
SU.BSURFACE EXPLORATION LOG
LOGGED BY: ENK DATE LOGGED: 4,27,84
JO8 NUMBER: 8430 Plate #12
I-
,. --
+;* 2
2 2 ; TRENCH NUMBER T-ll i” ; I f < 2 : do- 2 2’ ELEVATION
is zzk &Ii! MO
<Z ‘:; ;i
: it5
:zw
z- 2; 1;
0 2 : t2
t a 0 ;; -0 LGy 2:
z :, z z
5; 2 0
ii
=0
” OESCRIPTION
+” 0 0
SM Tan silty sand Dry Loose
l- (alluvium)
2-- -- SM Dark brown silty sand Humid Med.
Weathered sandstone Dense-
3’ Slightly porous Dense
4’
5’
6-
7- SM Brown silty sandstone Humid Med. - Dense- a- Dense -
9
Red brown -
BOTTOM
.l-
KETCHUM.ENGINEERING
SUBSURFACE EXPLORATION LOG
LOGGED BY: ENK DATE LOGGED: 27,a
JOB NUMBER: 8430 Plate #13
DIRECT SHEAR TEST RESULTS
DESCRIPTION
MAXlMUbi DENSITY and OPTIMUM MOISTURE CONTENT
AsrM 1557 A METHOD-
I
KETCSUM XNGINEERING 0-i RNK / OATE /ll /8f,
JOB YO. a430 1 Plate #14
I
US. Stondord Sieves
1” Yz’ I4 40 .x, WI llso . 7. Y : :: :
: ::
Ji
: ::
+ ; 1;
~’ __~~A _~:
~1 L$~ ty-
1~~17 : z :
,: : : y :
I
:
:,:: j -Loll. i. 2 ,LYe
PARTICLE
@mm S/z.+ lmnd
SIZE LIMITS
I
BGUlQER j COBBLES GRAVEL I SAN0 SILT OR CLAY
COWU Fin* CQarr. Mtdlum Fh. I I (12 in.) 3in. 3/4 in. No.4 No.lQ No.40 No. 200
u. s. STANQARO SIEVE SIZE
ORIGINAL GROUND / . .
/
. .
~: ., *.. COMPACTED FILL . : I
/. - * I . /
I, . : * . *. ., I>( :. : :
. . . : \a: *.I .
1
-. . 1 1 -. . .,
. . . ’ . . . . G
. . \- .
’ * *. *
1 . .- . - . . ,
. .
- . /’ I
.
/ /
7 ’ * * .
\
. *
* , -
s/
. I
Y-l---- ?-!INUS 1" CRUSt!ED ROCK
CO?-'PCETELY SURROI;FIDED
BY FILTER FABRIC, OR
CLASS II PERMEAFiI
I?ATER:AL
4" DiAMETER PERFORATED PIPE - MINIMUM 1% SLOPE
PIPE DEPTH OF FILL MATERIAL OVER SUBDRAIN ADS (CORRUGATED POLETHYLENE a TRANSITE UNDERDRAIN PVC OR ABS: SDR 35 :i SDR 21 100 SCHEMATIC ONLY
NOT TO SCALE
KETCHUM ENGINEERING -~ LINCOLN APARTMENTS
a/ DATE
TYPICAL CANYON SUBDRAIN .ENK 5/u/84 JOB NO. 8130 Plate #16
I--
TRAFGVERSE
WEAKENED
v ;: . . :_ :;,, ‘, .‘,‘, ..‘...‘. ‘.’ “.’ . ;‘. :. . . ‘. ,’ 1. ‘.‘. ji!lGT _,: .;: _._ . ..‘. .‘.‘.’ .‘.’ ” :, ‘. ‘_ ;. ‘,‘,‘.. ; ‘,‘..’ ‘, 51-10’ I
SLALS 114 EXCESS OF 10 FEET IN hIDTH SLAES 5 TO 10 FEET IN PiIDTH
PLAN
i<#T*S,
+ l/8 TO l/4
, , JUIIYI SC%LCK
6"x6"-lO/lO WWM
6"X6"-10/10 WWM
STRIP IN ADDITiON TO CON-
TINUOUS REINFORCEMENT
D&TAIL-WEAKENED PLANE JOINT
ii,TaSa
.- SETCHUM ENGINEERING~ LINCOLN APARTMENTS
BY DATE ENK 5/11/SL JOB NO. 8430 Plate #17
Appendix A, Page 1
,-
RECOMMENDED GRADING SPECIFICATIONS - GENERAL PROVISIONS
GENERAL INTENT
The intent of these specifications is to establish pro-
cedures for clearing, compacting natural ground, pre-
paring areas to be filled, and placing and compacting
fill soils to the lines and grades shown on the accepted
plans. The recommendations contained in the prelimin-
ary soil investigation report and/or the attached Special
Provisions are a part of the Recommended Grading Specif-
ications and shall supersede the provisions contained
hereinafter in,the case of conflict. These specifi-
cations shall only be used in conjunction with the soil
report for which they are a part. No deviation from
these specifications will be allowed, except where
specified in the soil report or in other written com-
munication signed by the Soil Engineer.
OBSERVATION AND TESTING
.-
A qualified Soil and Foundation Engineering Company
shall be retained as the Soil Engineer to observe and
test the earthwork in accordance with these specifi-
cations. It will be necessary that the Soil Engineer
or his representative provide adequate observation so
that he may provide an opinion that the work was or
was not accomplished as specified. It shall be the
responsibility of the contractor to assist the soil
engineer and to keep him apprised of work schedules,
changes and new information and data so that he may
provide these opinions. In the event that any unusual
conditions not covered by the special provisions or KETCHUM ENGINEERING
9508 MARKWOOO DR,, SANTEE, CA., 92071 619-446-3929
Appendix A, Page 2
,-
preliminary soil report are encountered during the
grading operations, the Soil Engineer shall be contacted
for further recommendations.
If, in the opinion of the Soil Engineer, substandard
conditions are encountered, such as; questionable or
unsuitable soil, unacceptable moisture content, inad-
equate compaction, adverse weather, etc., he will be
empowered to either stop construction until the condi-
tions are remedied or corrected or recommend rejection
of this work.
Test methods used to determine the degree of compaction
should be performed in accordance with the following
American Society for Testing and Materials test methods:
Maximum Density & Optimum Moisture Content -
A.S.T.M. D-1557-78.
Density of Soil In-Place - A.S.T.M. D-1556-64 or
A.S.T.M. D-2922.
All densities shall be expressed in terms of Relative
Compaction as determined by the foregoing A.S.T.M.
testing procedures.
PREPARATION OF AREAS TO RECEIVE FILL
All vegetation, brush and debris derived from clearing
operations shall be removed, and legally disposed of
off site. All areas disturbed by site grading should
be left in a neat and finished appearance, free from
unsightly debris.
I-- /
KETCHUM ENGINEERING
9508 MARKWOOO OR., SANTEE, CA?.. 92071 61S-446-3929
i-
,L
Appendix A, Page 3
Any abandoned buried structures encountered during
grading operations must be totally removed. All under-
ground utilities to be abandoned beneath any proposed
structure should be removed from within 10 feet of the
structure and properly capped off. The resulting de-
pressions from the above described procedures should be
backfilled with acceptable soil that is compacted to
the requirements of the Soil Engineer. This includes,
but is not limited to, septic tanks, fuel tanks, sewer
lines or leach lines, storm drains and water lines.
Any buried structures or utilities not to be abandoned
should be investigated by the Soil Engineer to deter-
mine if any special recommendation will be necessary.
All water wells which will be abandoned should be back-
filled and capped in accordance to the requirements set
forth in the Geotechnical Report. The top of the cap
should be at least 4 feet below finish grade or 3 feet
below the bottom of footing whichever is greater. The
type of cap will depend on the diameter of the well
and should be determined by the Soil Engineer and/or a
qualified Structural Engineer.
When the slope of the natural ground receiving fill ex-
ceeds 20% (5 horizontal units to 1 vertical unit), the
original ground shall be stepped or benched. Benches
shall be cut to a firm competent soil condition. The
lower bench shall be at least 10 feet wide or 1 l/2
times the equipment width which ever is greater and
shall be sloped back into the hillside at a gradient
of not less than two (2) percent. All other benches
should be at least 6 feet wide. The horizontai por-
tion of each bench shall be compacted prior to receiving
fill as specified hereinbefore for compacted natural
i- KETCHUM ENGINEERING
3506 MARKWOOD OR., SANTEE. CA.. 92071 619-446-3929
Appendix A, Page A
ground. Ground slopes flatter than 20 % shall be benched
when considered necessary by the Soil Engineer.
After clearing or benching, the natural ground in areas
to be filled shall be scarified to a depth of 6 inches,
brought to the proper moisture content, compacted and
tested for the minimum degree of compaction in the
Special Provisions or the recommendation contained in
the preliminary soil investigation report. All loose
soils in excess of 6 inches thick should be removed to
firm natural ground which is defined as natural soil
which possesses an in-situ density of a least 85% of
its maximum dry density.
FILL MATERIAL
Materials placed in the fill shall be approved by the
Soil Engineer and shall be free of vegetable matter
and other deleterious substances. Granular soil shall
contain sufficient fine material to fill the voids.
The definition and disposition of oversized rocks,
expansive and/or detrimental soils are covered in the
soils report or Special Provisions. Expansive soils,
soils of poor gradation, or soils with low strength
characteristics may be thoroughly mixed with other
soils to provide satisfactory fill material, but only
with the explicit consent of the Soil Engineer. Any
import material shall be approved by the Soil Engineer
before being brought to the site.
PLACING AND COMPACTION OF FILL
Approved fill material shall be placed in areas pre-
pared to receive fill in layers not to exceed 6 inches
K E I .C. I4 U M t!NGlNE~ERING
9508 MARKWOOO OR., SANTEE, CA., 92071 SIS-448-3929
Appendix A, Page 5
,,- in compacted, thickness. Each layer shall have a uniform
moisture content in the range that will allow the com-
paction effort to be efficiently applied to achieve
the specified degree of compaction. Each layer shall
be uniformly compacted to the minimum specified degree
of compaction with equipment of adequate size to econ-
omically compact the layer. Compaction equipment should
either be specifically designed for soil compaction
or of proven reliability. The minimum degree of com-
paction to be achieved is specified in either the Special
Provisions or the recommendations contained in the pre-
liminary soil investigation report.
,-
Whenthe structural fill material includes rocks, no
rocks will be allowed to nest and all voids must be
carefully filled with soil such that the minimum degree
of compaction recommended in the Special Provisions is
achieved. The maximum size and spacing of rock per-
mitted in structural fills and in non-structural fills
is discussed in the soil report, when applicable.
Field observation and compaction tests to estimate
the degree of compaction of the fill will be taken by
the Soil Engineer or his representative. The location
and frequency of the tests shall be at the Soil Engineer's
discretion. When the compaction test indicates that
a particular layer is less than the required degree of
compaction, the layer shall be reworked to the satis-
faction of the Soil Engineer and until the desired
relative compaction has been obtained.
Fill slopes shall be compacted by means of sheepsfoot
rollers or other suitable equipment. Compaction by
sheepsfoot rollers shall be at vertical intervals of
KETCHUM ENGINEERING
9508 MARKWOOO OR,, SANTEE, CA., 92071 61S-44e-392s
Appendix A, Page 6
not greater than four feet. In addition, fill slopes
at ratios of two horizontal to one vertical or flatter,
should be trackrolled. Steeper fill slopes shall be
over- built and cut-back to finish contours. Slope com-
paction operations shall result in all fill material
six or more inches inward from the finished face of the
slope having a relative compaction of at least 90%
of maximum dry density or that specified inthe Special
Provisions section of this specification. The compac-
tion operation on the slopes shall be continued until
the Soil Engineer is satisfied that the slopes will
be stable in regards to surficial stability.
. I-
Slope tests will be made by the Soils Engineer during
construction of the slopes to determine if the re-
quired compaction is being achieved. Where failing
tests occur or other field problems arise, the Con-
tractor will be notified that day of such conditions
by written communication from the Soil Engineer in
the form of a daily field report.
If the method of achieving the required slope compaction
selected by the Contractor fails to produce the neces-
sary results, the Contractor shall rework or rebuild
such slopes until the required degree of compaction is
obtained, at no additional cost to the Owner or Soils
Engineer.
CUT SLOPES
c-
The Engineering Geologist shall inspect all cut slopes
excavated in rock or lithified formational material
during the grading operations at intervals determined
at his discretion. If any conditions not anticipated
in the preliminary report, such as perched water, seepage,
KETCHUM ENGINEERING
9508 MARKWOOO OR., SANTEE, CA., 92071 SIS-44e-3929
. .
Appendix A, Page 7
,--
lenticular or confined strata of a potentially adverse
nature, unfavorably inclined bedding, joints or fault
planes are encountered during grading, these conditions
shall be analysed by the Engineering Geologist and Soil
Engineer to determine if mitigating measures are neces-
sary .
Unless otherwise specified in the soil and geological
report, no cut slopes shall be excavated higher or
steeper than that allowed by the ordinances of the con-
trolling governmental agency.
ENGINEERING OBSERVATION
Field observation by the Soil Engineer or his represen-
tative shall be made during the filling and compacting
operations so that he can express his opinion regarding
the conformance of the grading with acceptable standards
of practice. The presence of the Soil Engineer or his
representative or the observation and testing shall not
release the Grading Contractor from his duty to compact
all fill material to the specified degree of compaction.
SEASON LIMITS
Fill shall not be placed during unfavorable weather
conditions. When work is interrupted by heavy rain,
filling operations shall not be resumed until the proper
moisture content and density of the fill materials can
be achieved. Damaged site conditions resulting from
weather or acts of God shall be repaired.
K E TC # U I# ENGINEERING
9508 MARKWOOO OR., SANTEE, CA., 92071. sis-048-392s
Appendix A, Page 8
,-- RECQMMENDED GRADING SPECIFICATIONS-SPECIAL PROVISIONS
The minimum degree of compaction to be obtained in com-
pacting natural ground, in the compacted fill, and in
the compacted backfill shall be at least 90 percent.
Detrimentally expansive soil is defined as soil which
an expansion index (EI) of greater than 20.
Oversized fill material is defined as rocks or lumps
over 6 inches in diameter. At least GO percent of the
fill soils shall pass through a No. L U. S. Standard
Sieve as determined by weight.
Transition Lots: Where transitions between cut and
fill occur within the proposed building pad, the cut
portion should be undercut a minimum of one foot below
the base of the proposed footings and recompacted as
structural backfill.
KETCHUM ENGINEERING
9503 MARKWOOC CR,, SANTEE, CA., 92071 SIS-448-3929