HomeMy WebLinkAboutCT 80-41; 14 UNIT CONDOMINIUM; SOILS INVESTIGATION; 1981-02-25•
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PHILIP HENKING'BENTON ,
I'IIESIDENT • CIVIL ENGINEEII
Roy J. Ward Company
1207 Elm -Avenue, Suite D
Carlsbad, California 92008
BENTON ENG~Ne:ER.ING, INC.
APPLIED SOIL MECHANICS -FOUNDATfONS .
111140 RUFFIN ROAD
SAN DIEGO, CJ>.LIFORN)A 92'123
February 25, 1981
Attention: Mr. Bob Thompson .
TELEP'HONE (714) 565·1955
• Gentlemen:
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Thisis to transmit 1'0 you six copies of our report of Project No. 81-2-6A entitled, "Soils
Inv~sti9ation, Proposed 14 Unit Condominium, Lot 40 of La Costa South Unit No.1,
Navarr'q Drive, Carlsbad, California" "-dated February 25, 1981.
If you Sh9Uld have any questions concern-ing any of ,the data presented in this report,
pJeas~ contact us.
Vety truly yours,
• BENTON ENGINEERING, INC.
~. x<.~~ ~entonl Ci~eer •
PHB/ir
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SOILS INVESTIGATION
PROPOSED 14 UNIT CONDOMINIUM
LOT 40 OF LA COSTA SOUTH UNIT NO.1
NAVARRA DRIVE
CARLSBAD, CALIFORNIA
For the
Roy, J. Ward Company
PROJECT NO. 81-2-6A
FEBRUARY 25, 1981
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TABLE OF CONTENTS
SOILS INVESTIGATION • Introduc~ion ........................................... It ......... .
Field Investigation ......................... ~ ........• -.••..••••••••• !.
Loboratory Tests ........................ '! ...... Ii ..................... ,~
• DISCUSSION CONCLUSIONS AND RECOMMENDATIONS
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Soil Conditions ...................................................... ' .•..•
Conc-Iusions and Recommendations ••••••••••••••••••••••••••••••
Re'commendations ................................ -. ..................... .
'Retaining Walls .......... '" ..................................... .
Site" Grading ............ " .... ' ....................................... .
DRAW IN'G TITLE
Location of Test Borings ........................................... .
Summary Sheets:
Boring No. ' ...............•.•.• -•.•..• ' .........•..••.
Boring No.2 ................... ~-............ " ......•.
B'oring No.3 .................................................. ,
Log A -East S'lope ••••••••.•.•••••••• I,' •• ~ •••••••
Log B -South Slope ....................... ' ..••••••
Log C -West Slope ••••••.•.••••••••••.••. ~ ••••••
Consolidati'on Curves •.......•..•.•..•..•......••...... , ..••.•.
APPENDICES
StClndard Specifications for Pla~ement of Compacted Filled Ground ••
(ASTM D 1557-70 -90% -25/5 layers)
Unified Soil Classifi cation Chart •••.•• '! •••••••••••••••••••••••
Sampling, etc ....•.......•• ~ •.•.••..•.•....••.........• ~ •.•••
BENTON ENGINEERING. INC.
Page No.
1 and 2
2 and ~
3 and 4
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4 and 5
5
Drawing No .•
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2
3
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4
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5
6
.AA
A
B
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PHILIP HEN KING BENTON
PRESIDENT· CIVIL ENGINEER
·In trodu ction ,
BENTON ENGINEERING, INC.
APPLIED .SOIL MECHANICS -FOUNDATIONS
111140 RUFFIN ROAD
SAN DIEGO; CALIFORNIA 92123
SOILS JNVESTIGAnON TELtl'HONE (714) 15815·1511515
This is to present the results of a soils investigation conducted at the site
for a proposed 14-unit condominium building located on fhe south. side of Navarra Drive
• in Carlsbad, California. It is understood an underground garage will be located beneath
the proposed buildings and most'of the excavation for the lower level parking area had
already been completed -at the time of field exploration on February 4, 1981 • . -
The obiectiv~s of the .investigation were to determine .the general subsurface soil
conditions at the site and sufficient physical characteristics of the soils so that soil parameters
• . and engineering recommendations could be presented for the design of the proposed building
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foundations and retaining walls. In order to.accomplish the objectives, three borings were
drilled, the soils exposed on the existing ~anks' were logged, and undisturbed samples were
obtain~d for laboratory testing.
Field Investigation
Three borings were drilled with a truck-mounted rotary bu~ket-typedrill rig at
the apprOXimate locations shown on the attached Drawing No.1, entitled "Locat.ion of Test
Borings." The borings were ddlled to·depths of 8 to 10 feetbelqw the existing ground surface.
A cont.iriUOUS log of the soils encountered in the borings and exposed on the existing banks
was re·corded at· the time of drilling and is shown in detail on Drawing Nos. 2 to 5, inclusive,
each entitled "Summary Sheet. II .
The soils were visually classified by field identification procedures in accordance
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with the Unified :$oil ClasSification Chart. A simplified description of this classification system,
is presented in the attached ~pendix A at the end of thisrepQrt.
Undis~urbed samples were obtained at frequent intervais, where possible, in the soils
ahead of the drilling. The drop weight used for drIving 'the sampling tube int~ the soils ~as
the !'Kell~1I bar of the drql rig which weighs 2200 pound~, and the average drop wQS 12 inches.
The general' procedures used in field sampling are' described 'under "Sa~plingll Tn Appendix B.
Laborator):, Tests
• Labor~tory ~ests wer~ performed on all undisturbed samples of the soils in' order to
determin,e the dry :density I moisture content, anc:l shearing strength. The resul ts of these tests . ' ,
are pres~nted on Drawing' Nos. 2 and 3. Consolidation' teSts, were performed on representative
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• samples in orde,r to determIne the load-settlement characterisHcs ~f the .. soils and the results of
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these tests are presented graphically on Drawing No.6, entitled JlConsolidation Curves. II
In addition to the above laboratory tests, ,expansion tests were performed on the
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silty clay soil encountered to determine its volumetric change characteristi cs with change in
moisture' content: The recorded expansions of the samples are presented as fol,lows:
Depth of
Boring Sample Sample
No. No~ in Feet .
2 2 7.0
Soil Description
Silty:clay ,
Pe rcent Expansion
Under Unit Load of
144 Pounds per Square
Foot from Field
Mo'isture to Saturation
0.90
Percent Expa'nsion
Under Unit Load
of 500 Pounds per
Square Foot from
Air Dry to SaturatTon
1.82'
'? Direct shear tests were perfQrmed on selected undisturbed sampJes that were saturated ('0.1
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co . 'and drained prior to testing. The resu I ts of these tests are .presented as follows: .-0
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Boring: 1, Sample:' 1
Depth: 1.5 -2.0 F:~et
BOring: 2, Sample: ·1
Depth:: 1 .5 -2. 0 Fe~t ) )
Normal,
Load in .
kipsA9.n
0.5
1.0
2.0
'0.5
1.0
2.0
o -3-.
Shearing-
. Resistance
kipsLsq ft
0.39
1.40
2.22
1002
1.89
2.01
Angle ,of
Internal
. Friiction
DE;lgrees
40
33.5
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Apparent
Cohesion
Ib/sq ft
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.690
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The ~ieneral procedures used for the preced~ng laboratory tests are described briefly
in Appendix B.
, -, DISCUSSION, CONCLUSIONS AND.RECOMMENDATIONS . " -, ... ,
Soi I Conditions
Medium compact to compact fine to medium sand with scattered gravel and f:i!1e sandy
clay nodules was encountered to 6.3 feet in BOring No.1. This was underlain by' compqct . ,
• gravelly fine to medium sand to 7.0 feet and firm graveHy clayey fine to medium .sand between
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. 7.0 and 10. 0 feet, the depth of exploration.
In Boring No.2 firm clayey fine to med.ium. sand ~ith s'cattered gravel and cobbles
w~s found to 2.4 feet and ~/as underlain by. firm gravelly clayey fine to medium sand to 5.6
feet, firm silty clay between 5.6 and 8.5' feet I and firm grave'lIy clayey-fine to medium solid
to the limit of explor~tion at 10.0 feet.
Firm gravelly clayey fine to medium sand was encountered '1'0 8.0 feet, the limit of
. exploration in Boring No.3 •
Free ground water was not encountered in the exploration borings.
The soils exposed near the central portion of the existing slope along. the east property
line were primarily silty sands and slightly silty sands. Fine sandy clays.''!Yere observed to (I
depth,of 8.0 feet on the south slope area and gravelly 'slightly silty fine to coarse sand was
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found between 8.0 and 10.0 feet, the bottom of the slope. The soils exposed near the middle
BENTON ENGINEERING. INC.
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of the westerly sl6.pe ,consiste8 of slightly silty fine to medium sand to 1.0 foot, fine to medium
sandy c1ay:betWeen 1.0 dnd 3.0 feet, silty fine to medium sand from 3.0 to 4.0 feet; and
• gravelly slightly silty fine to coarse sand to 5.0 feet at the bottom of the slope.
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Condu~ions and Recommendations
H is concluded from the field investigation and the results of laboratory tests that
the soils similar to those e;ncountered bel.ow a depth of one foot at the 'borin9 .locations are
suitable for support oJ the proposed buildings. The results of t~e expansion test~ indicate that
,the sHtyclay,enc;o.untered between 5.6 and,8.5 feet in Boring No. 2. would be considered to
have a low expansion potential and, therefore spe<?ial design and precautions for expan~ive soil
conditions will' not be required.
• Recommendations
Footings at least one foot in width and pl~ced at a minimum' depth o{ one foot belo~
the lowest adjacent,natural ground surface may be designed using a safe aHowable bearing • , "
value of 2,400 pounds per square foot. This value may be increased at-the rate of 600pounds
per square foot for each additional foot of width and an'additional ;ate of 1,000 pOl,Jnds per
• square foot for each additional foot of depth below one foot to a maximum of 4,000 pounds per
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square foot. These values are for dead plus live loads and may be increased one-third for .
combined dead, live, wind and seismic loads.
Based on the results of th~ load-consolidaHon tests, the 'settlement of a continuous
footing 18 inches wide and supporting a uniform loa~ of 3,600 pounds per I ineal foot is esfimated
to be on the order of 1/8 inch •
~etaining Wall~
The design active pressures for retaining walls with a horizon~al surcharge ~f soil
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'behind the wall are recommended to be'an equivalent fluid pressure of 35 pounds per cubic'
foot it unrestrained at the ~op and are re commended as a pressure of 22 "H" pounds per
square foot (w.here "H" is equC11 to the height of the wall in feet) in the middle 60 percent
BENTON ENGINEERING. INC,
-s-• cf the wall where the wolf Is restrained. Where retainIng walls have a slcping 2 horizontal to
1 vertIcal surcharge behind the wall, then the equivalent' f.luid pressure for the unrestrained' wc:rll
is ,recommended to be Increased to' 45 pounds per eubi c foot and for the pressure on a restrained • wallis recommended to be 28 IIHIJ pounds per square foot in 'the middle 60 percent.
, These design pressures assume that the hackfiH solis behind the walls ate silty scnd, sand
• or'gravel and that either Weep holes or perforated pipes are installed at the base of the walls
in ;ord~r to prevent hydrostatic pressures from developing behind the walls.
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The allowable passive pressure for footings cast directly against the undisturbed natural
'soils ts 360 pounds per square foot at the depth of one foot and this value maybe increased at th~
rate ~f 180 pounds per square foot! for each additional foot in depth. The allowable rrl etion factor
for the dead ioad at the bottom of a concrete footing is 0.4 .. The allowable passive pressure
value may 'be c()mbined' with the friction factor to determine t~e total allowable re$iStance to
lateral movementS.
• Site ,Grac:JinQ 1.~ .
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It is recommended that any additional filled ground placed on the site should be placed
under engineering insp!-,ction and should be uniformly compacted to at least 90 percent of
mcQ(Imum dry density in ~ccordance with the app.licab.le sections of the attached Appendix AA
entitled "Stand!lrd Specifications for Placement of Compacted Filled Ground. II
Respectfvny~ubmitted,
B61'ITON ENGINEERING, INC.
By.R.c?~. '
~ ,R.t. Remer ~. ~. Re~i.W8(/ bY~. . .. ~
. -.r,;Henton;iVtl~·
ReE No. 10332
RCIVPHB/tr
BENTON ENGINEERING. INC.
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SUMMARY SHEET
BORING No._-!.l __
ELEVATION ___ _
.., _ :;:..":":";:.:. Brown, lv10ist I Medium Compact
1 _ . :.: .. ::::.::.:.<.:::. With Scattered Gravel to 311
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:' .. ::.:::,: Occasional Lenses With 15 to -CD' ':.:.:<'::::.): 20010 Gravel, Few Nodules Of
2 -':::,:,\\:,,:; Fine Sandy Clay -:: . .'.:.' "----...:...----:.------IFINE TO MEDIUM
3=>: Compad SAND
4 CD : ... ;.-;:: .... = {.<:\/:).
> >. CI' w· a:1-Q~~ 1-'" ul-w~ in II. ·a:ZII.
Zf ""'I-> ~.:) ~~~ w_ W CI1 a:. Q~ ·w~ U:i~ >81 %inf >. CI1
W
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a: II. l!i"'" a:~
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2.4 3.7 ~5.5 p.32
4.8 4.3 ~01.0 0.57
: = ® bii;.:.:r(,;.,.;["+)~ •• f--____________ ---=.f--____ ..,...-___ -+9_,·._6-+_5_. 7-+1 __ °5_° ..... 7-+-°_0 9--11
-.~\:o:~~~ Brown, Moist, Compact, Wnh GRAVELL Y
7 -~~ •. 6.~~: 40 to 50% Gravel and Cobble FINE TO MED.IUMri---+---+-....,....,.-+----t
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..,.
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'.' 'A" to 611 SAND · ~ :,,: . , '--___________ -+---'"'" _____ -.J
GRAVELLY
CLAYEY
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PROJ'ECT NO.
81-2-6A
Brown, lv1oist, Firm~ With 30 to
40% Grave'-and Cobble to 6 11
FINE TO MEDIUM
SAND
o Indi cates Undisturbed Drive Sample
BENTON ENGINEERING; INC.
DRAWING NO.
2
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t= ... Ct· 1&1'
,1&1 '1&1« SUMMARY SHEET « ... o~~ ... ... u'"
1&1 "'1&1 ... ~o 1&1 I!:: jY: z~
~ ~4:i -0. CD -UCD zle ... ::;»
x ~~. ~U::E 2 1&1::;)
BORING NO. 1&1-I&Itn« o~
t: -> I&I~ i&:i~ x~f
1&1 z ~0 ELEVATION >. >1 00
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_ ... 111-
O. a:~ ~ ... «~
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" u • .. . Brown, N\oist, Firm, With -. . CLAYEY ." ...... : Scattered Grave I and Cobble 1-FINE TO MEDIUM : 'fo 411, and Clay Nodules -CD ....... " SAND ..... ' .' .. 101.3 2-.......... 4.8 22.7 1,.20
.. .. .. .. .. .-",.' .-~ • .....,
3-· •• 0,., • Brown, Moist, Firm, With 30% ~-~ .... ~ ..
" ....... ~ .. Gravel and Cobble to 6", GRAVELLY -., . .r ~ ••
'QO ~~ .• Occasional Clay Nodules CLAYEY 4-.. t> -. -._ ....
~ , .... , "'.'" ",.
FINE TOMEDIUM
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5-· .~ ...... SAND
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• , ',f" -;9 .... ""'i
6-,"" '" Brown, Moist, Firm, Lit.tle
"" " Porous, With Occasional -@ '." "'"''
7"" ,'\.'\.'\. "" Gravel to 3" 7 .2. 23.3 101.7 2.23 . , "'" 1
."" '" SILTY CLAY • -""" 8-,'"'''' ,
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9-.("It' .... "-Brown, Moist, Firm, With 300k GRAVELLY ..... ,,:; •. 'n'
... 0. .. Gravel to 311 CLAYEY -,a..v •• ;.;-x;l. ,,, ......... FINE TO MEDIUM • " SAND
• Boring No. 3
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.. '!. .. " .. : Brown, N\oist, Compact, Firm, ..-.
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"" ...... : With 30% Gravel and Cobble 1""
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<.: :.: ~ : :to 6 11 l ~
-............ . .. ........
c 0
2-"-" ........ ... ," ...... With Gravel and Cobble to 9" -.......... -E 0
U
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3-............
,eo" ...... GRAVELLY .......... • "E 0
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-.. ~ ...... Gray Brown, Wi th Gravel and CLAYEY 4....;. ........ " Cobble to 6" FINE TO MEDIUM -,
........ SAND
0 c.::: 5-· ..... Brown -....... · ..... • 1&1 :E
6-' .. --.... .... -.... 4: -........
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CD ~ 7"'-· ......
• ••• * * -' *0-• * *. .......
n • • * ••• v . DRAWING NO.
• PROJECT NO.
81 ... 2-6A BENTON ENGINEERING, .INC, 3
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SUMMARY ,S.HEET
log A
East Slope
. ~~own,V~'tY}~~ist"L.o~se, ~ SILTY
~. ~casi'ona}'Grovelwlth'Sllght FINE TO COARSE
L ... ·' .' ~ lay Biiiaer SAN D
~~~,.~~. '~~",," ~'W~er..c;....:..vF~irm~ _____ . ___ ...... 11. GRAVELLY
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w·:':: >' -~ a: II. Q
-~~ Br?wn, V.ery Noist, Medium. SLIG HTL Y SILTY J ~:~tFmn, With 40% Gravel to 111 FINE TO COARSE r+--+--+---r--"'"
•. It~ ~'); SAND -~~~ ~~----------~--~--------~I
.4,-~.~ Brown, Very Moist, Firm, SILTY
-. ~:~Occasi9nal Grovel to 111 FINE TO MEDIUM
5-~~ '~ SANb
I-@L .... -"'--......u·~ .. ~~~·~UIO~;a. Brown, Very Moist I Firm, With GRAVELLY'
'" 200~ Gravel to 2/1 SLIGHTLY SILTY
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1-
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2--
3--
4-.-
5--
6 ....
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8-
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9--
1(\
log, B
,South Slope
':::. : ::: Brown, Very Moist, Soft,
:' :::::.' Occasional Gravel
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, :.::. ::.":,,.: Firm ............
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........ "
.... " .. ,
" .> ....... .
.. -; ..... "
.....
'11< :' .. -:', Brown, Very Moist, Compact,
. . With 2(J'1o Gravel to 2"
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I!~"-"';~)i ~~
FINE TO COARSE
SAND
FINE SANDY
CLAY
GRAVELLY
SLIGHTLY SILTY
FINE TO COARSE
SAND
BENTON ENGINEERING, INC. PROJECT NO.
81-2-6A
DRAWING NO.
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CONSOLIDATION CURVES
LOAD IN KIPS PER SQUARE FOOT
0:2 0.4 0.6 0.8 I 2 4. 6 (3 .. -10 16 o ~~rrmmm~~~mmwmmm~~TlTI~~rrnTmmmrrmmTrrn~~mmmm~~~~
en en-
W z ::.:: u
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W ...J a:. ::!:
1
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4
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1
2
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lL. o
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U
0:: W' a:.
z o
1
I-~ 2
...J o en g 3 u
o
1
2
3
4
2'
1
2
4'
~::~F=t~~+=tr1J~;;.:.;.:..;~~~r~I~..::.;:.:.::lrI11~Bo~ ring: 2
~_--I-_--I-"::::::::=+--d--I--I-+-l---"::::::::~=--=----I-----t---+-.\--I Sample: 1 Depth: 2'
. Boring: 2
Sample: 2
1-----i---'-I--_+-I--+=~I=010:------+---+--+~-+---I--I Depth: 71
• INDICATES PERCENT CONSOLIDATION AFTER SATURATiON
PROJECT NO.
81-2-6A BENTON ~NGINEERING INC.
DRAWING NO.
6
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BENTON ENGINEERING, INC.
APPLIED SOIL MECHANICS -FOUNDATIONS
111140 RU FFIN ROAD
SAN DIEGO, CALIFORNIA 92123
PHILIP HENKING BENTON
PRESIDENT -CIVIL ENGINEER TELEPHONE (714) '565-1955
APPENDIX AA
STANDARD SPECIFICATIONS FOR PLACEMENT
OF COMPACTED FILLED GROUND
1. General Description. The objective is to attain. uniformity and adequate internal strength
in filled ground by proven engineering procedures and tests so t,hat the proposed structures
may be safely supported. The procedures include the clearing and grubbing, removal of
existing structures, preparation of land to be filled, filling of the land, the spreading, and
compaction of the filled areas to conform with the lines, grades, and slopes as shown on the
accepted plans.
2.
The owner shall employ a qualified soils engineer to inspect and test the filled ground as
placed to verify the uniformity of compaction of filled ground to the specified 90 perc~nt
of maximum dry density. The soils engineer shall advise the owner and grading contractor
immediately if any unsatisfactory conditions are observed to exist and shall have the
authority to reject the compacted filled ground until such time that corrective measures
are taken necessary to comply with the specifications. It shall be the sole responsibi lity
of the grad ing contractor to achieve the spec ified degree of compaction.
Clearing, Grubbing, and Preparing Areas to be Filled.
(a) All brush, vegetation and any rubbish shall be removed, piled, and burned or other-
wise disposed of so as to leave the areas to be filled free of vegetation and debris.
Any soft, swampy or otherwise unsuitable areas shall be corrected by draining or
removal, or both.
(b) The natural ground which is determined to be satisfactory for the support of the filled
ground shall then be plowed or scarified to a depth of at least six inches ~6"), and .
until the surface is free from ruts, hummocks, or other uneven features which would
tend to prevent uniform compaction by the equipment to be used.
(c) Where fills are made on hillsides or exposed slope areas, greater than, 10 percent,
horizontal benches shall be cut into firm undisturbed natural ground in order to provide
both lateral and vertical stability. This is to provide a horizontal base so that. each
layer is placed and compacted on a horizontal plane. The initial bench at the toe of
the fill shall be at least 10 feet in width on firm undisturbed natural ground at the eleva-
tion of the toe stake placed at the natural angle of repose or design slope. The soils
engineer shall determine the width and frequency of all succeeding benches which wit-I
vary with the soil conditions and the steepness of slope.
• APPENDIX AA
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\(d) After the natural ground has been prepared, it shall then'be brought to the proper mC)is~
ture content and compacted to not less than ninety percent of maximum density in
• accordance with A.5. T.M. 0-1557-70 method that uses 25 blows of a 10 pound hammer
falling from 18 inches on each of 5 layers in a 4" diameter cylindrical mold of a 1/~Oth
Gubic foot volume.
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3. Materials and Special Re uirements. The fill solis shall cpnsist of select mqterials So graC:lec;/
. at at least 40 percent of t e material passes a No.4 sieve. This may be obtQilied from
the excavotion of banks, borrow pits of any other approved sources and by mixi~ soils from
one or more sources. The material used shall be free from vegetable matter, and' other de ...
leteriQl,Js substonces, and shall not contain rocks or Il,.Imps ofgreate'r than 6 inches in diamete,r.
If excessive vegetation, rocks, or soils with inadequate $trength or other I,.Inacqeptqble. phys'icql
characteristics are encountered, these shall be disposed of in woste areas as shown 011 the '.
. plans or as directed by the soils engineer. If during grading operofions, sons not emc;ounter:eQ
one;! tested in the preliminary investigation are found, tests on these soils shall be perform¢c;lfO
determine their physical characteristics. Any special treatment recommencfed in: the pre'liminQfY
or subsequent soil reports not covered herein shall becom~ an ade;!endum to,these specific.afions .•..
The testing and specifications for the compQction of subg rade , subbase , and base materials for
roads, streetsr highways, or other public property or rights-of ... way shall be in Q9cordanc~
with those of the governmental agency having jurisdiction.
4. Plocing, Spreading, and Compacting Fill Materials.
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(a) . The suitable fill materiol shall be placed in layers which, when cornpactedsh'QI'I not
exceed six inches (6 11
). Each layer shall be spread evenly and shall be ,throughly .
mixed during the spreading to insure uniformity of material qnd mQisture 'in each laye,:' .
(p)
(d).
Vv'hen the moisture content of the fi II material is below' that specified by the soils engi'near, .
water shall be added until' the moisture content is near optimum QS specified by the' .' .
soils engineer to assure thorough bonding during the compacting process·. .
'lYhen the moisture content of the fi II material is above that specified by the' soils .
engineer, the fi II material shall be aerated by blading and scqrifying or other satis-
factory, methods unti I the moisture content is near optimum as specified by' the soils, .
engineer. .
After each layer has been placed, mixed and spreQd evenly, it shall be thorol,.lgh Iy
compacted to not less than ninety percent of niaximum density in ac;cordance with
A.S.LM.0-1557-70 modified as described in 2 (d) above. Compaction shall. be
accomplished with sheepsfoot rollers, ml,lltiple-wheel pneumatic-tired rollers, or other
approved types of compaction equipment, suoh as vibratory equipment that is speciall.Y
designed for certain soil types. Rollers shall be of such design that they wi II .be Qble'
BENTON ENGINEERING. INC.
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APPENDIX AA
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to compact the fill material to the specified density. Roll ing shall be accOmplished
while the fill material is at the specified moisture content. Rolling of each layer
shall be continuous over its entire area and the roller shall make sufficient trips to
insure that the desIred density has been obtained. The entire areas to be filled shall
be compacted.
(e) Fill slopes shall be compacted by means of sheepsfoot rollers or other suitable equip-
ment. Compacting operations shall be continued until the slopes are stable but not
too dense for planting and until there is no appreciable amount of loose soil on the
slopes. Compacting of the slopes shall be accomplished by backroll ing the slopes in
increments of 3 to 5 feet in elevation gain or by other methods producing satisfactory
results.
( f)
(g)
Field density tests shall be taken by the soils engineer for approximately each foot in
elevation gain after compaction, but not to exceed two feet in vertical height
between tests. Field density tests may be taken at intervals of 6 inches in elevation
gain if required by the soils engineer. The location of the tests in plan shall be so
spaced to give the best possible coverage and shall be taken no farther apart than
100 feet • Tests shall be taken on corner and terrace lots for each two feet in eleva-
tion gain. The soils engineer mqy take additional tests as considered necessary to
check on the uniformity of compaction. Where sheepsfoot rollers are used, the tests
shall be taken in the compacted material below the disturbed surface. No additional·
layers of fill shall be spread until the field density tests indicate that the specified
density has been obtained.
The fill operation shall be continued in six inch (6 11) compacted layers, as spedfied
above, until the fill has been brought to the finished slopes and grades as shown on
the accepted plans.
5. Inspection. Sufficient inspection by the soils engineer shall be maintained during the fill-
ing and compacting operations so that he can certify that the fill was constructed in accord-
ance with the accepted specifications.
6. Seasonal Limits. No fill material shall be placed, spread, or rolled if weather conditions
increase the moisture content above perm issible I im its. When the work is interrupted by
rain, fill operations shall not be resumed until field tests by the soils engineer indicate that
the moisture content and density of the fill are as previously specified.
7. All recommendations presented in the IIConclusions" section of the attached report are a part
of these specifications.
BENTON ENGINEERING, INC.
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PHILIP HENKING BENTON
PRESI[)ENT • CIVIL. ,ENGINEER
SOIL DESCRIPTlQN
BENTON ENGINEERING. INC.
APPLIED SOIL MECHANICS -FOUNDATIONS
111140 RU FFIN ROAD
SAN DIEGO, CALIFORNIA 92123
APPENDIX A
Unified Soi I Classification Chart*
GROUP
SYMBOL
TYPICAL
NAMES
I. COARSE GRAI NED, More than half of
material is Iqrger'than No. 200 sieve
size ;**
TEL.EPH9NE (714) J5~15.1$155 ;,
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GRAVELS
More 'than half of
coarse fraction is
CLEAN GRAVE LS GW Well graded gravels;,grqvQI ,..sand ~,i><hir.~h'.·"
little or no fines. .-. '. .
GP Poorly graded grav~ls, gr<:ivel ... ~ci-nc.l
larger thon No.4 mixtures, little 0r no fil'\e~-, -.
sieve ~ize bJ,)tsma"~r GRAVE lS WITH FINE S
than 3 inches (Appr.eciable amount
of F'ines) • GC
GM Silty gravels, poorly graded erqye'[,.,·· "
sand-silt mixtur~s. . .' -.;.. .:
Clayey gravels, poorry graded gfqve.I·;"'·
t" I
sand-clay mixtures. . -_,
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SANDS c; LEAN SANDS SW Well graded sand, ~raveny ~ancls,-,Ii,t.tl~; _'
Mor~ than half of or no fines.
coarse fraction is SP Poorly graded sands, gravelly -ssmd~, :'1.
~mqller than No.4 little or no fines. '. , , -
sieve size ' SANDS WITH FINES SM Silty sands, Poorly'9r?q~d-s~;md-~nt . ) .'
(Appreciable amount mixtures. : . '"
of fines) SC Clayey sands, poorly grad~d sqhd-c_I~y.
mixtures.
II. FINE GRAINED, More than half of
material is smaller than No. 200
sieve si;ze. ** SILTS AND CLAYS ML Inorganic silts and very fi!le scmd~{ ~(;~k
flour, sandy silt or clayey-.silt"'s,C;rnd.-
mixtures with sl ight pl<;isticity.
liquid limit CL Inorganic clays of low tOfTledillm pies .. '
Less than 50 ticity, gravelly clays, sandy qla}"s,
silty c lays, lean clays.
OL Organic silts and organic silty-c.lays pi
low plasticity.
SILTS AND CLAYS MH Inorganic si Its, mic(;iceous or diqtqmqq~o\J~
fine sandy or silty soils, elastic; silts.-. -
Liquid li mit CH Inorganic clays of high 'plastic;~ty, fat
Greater than 50 clays.
OH Organic clays of medium to hig'h
plasticity
III. HIGHLY ORGANIC SOILS PT Peat and other highly orgQnic SQils~ ,
...• ~ * Adopted by the Corps of Engineers and Bureau of Reclamation in January, 19p2.
** All sieve sizes on this chart are U. S. Standard.
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PHILIP HENKING BENTON
PRESIDENT· CIVIL ENGINEJ;:R
Sampling
BENTON ENGINEERING, INC.
APPLIED SOIL MECHANICS -FOUNDATIONS
51140 RUFFIN ROAD
SAN DIEGO. CALIFORNIA 92123
TELEPHONE /71'1) 5E!l5.19~5
APPENDIX B
The undi~turbed soil samples qre obtained by forcing a special sampling tube into th~
undisturbed soils at the bottom of the boring, at frequent intervals below the ground ~urf~ce.
The sampling tube consists of a steel barrel 3.0 inches outside diameter, with ,0 ~peGiQI cuttil'lg
tip on one end and a double ball valve on the other, and with a lining of twel:v,e thin b'ross
rings, each one inch long by 2.42 inches inside 9iameter. The sampler, connectE!d j'o pi twelve
inch long waste barrel, is either pushed or driven approximately 18 inches into the soil at:)d a
six inch section of the center portion of the sample is taken for laboratory tests,. the soH b€1ing'
sl-i II confined in the brass rings, after extraction from the sampler tube. The samples ar~, takt;:l,n' .
to the laboratory in close fitting waterproof containers in order to retain the field moisture uritil
completion of the tests. The driving energy is calcu!ated as the average energy in foot-kips.
required to force the sampling tube through one foot of soil at the'depth at which the sqmple is'
obtained. .
Shear Tests
The shear tests are run using a direct shear machine of the strain control type in w~iqh
the rate of deformation is approximately Q.05 inch per minute. The machine is so qesig"ned trhQt
the tests are mode without removing the samples from the brass liner rings in which they qrEl '
secured. Each sample is sheared under a normal load equivalent to the we'ight of the s9i1 above.
the point of sampling. In some instances, samples are sheared under various normal loads ih .
order to obtain the internal ang Ie of friction and cohesion. Where considered necessary, samples
are saturated and drained before shearing in order to s~mulate extreme field mQistt;Jre cotldit·i~?I'l~ •.
Consolidation Tests
The apparatus used for the consolidation tests is designed to receive one of the onE! inch
high rings of soil as it comes from the field. Loads are applied in several increments to th~ upper
surface of the test specimen and the resulting deformations are recorded at selected time ;ntervQls'
for each increment. Generally, each increment of load is maintained on the sample until the rate'
of deformation is equal to or less than 1/10000 inch per hour. Porous stones are placed in c;::ontact
with the top and bottom of each specimen to permit the ready addition or release of water.
Expansion Tests
One inch high samples confined In the brass rings are permitted to air dry at 1050 F for
at least 48 hOl,Jrs prior to placing into the expansion apparatus. A unit load ot 500 pound~ per,
square foot is then applied to the upper porous stone in contact with the top of each sample. Water
is permitted to contact both the top and bottom of each sample through porous stones. Confinuou~
observations are made until downward movement stops. The dial reading is recorded Ql1d expan~ion
is recorded unti I the rate of upward movement is less than 1/10000 inch per hour.
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LEGEND
-$-lt1dicares Approximate l.ocafion of' Te.s~ Borin<3
BENTON ENGINEERI'NG, INC.
SAN DIEGO, CALIFORNIA
LOCATiON OF TEST 60R1NG5
PItOPOSED 14 UNIT CONDOMINIUM ,
LOT 40 OF LA COST~ SOUTH UNIT NO.1
N~VA't..~"" DIt\'IE
CI\~L$2>~tl, C~l.IFORN lA.
SCALE : '''='lO'
DRAWN :l<.L.Greel1 C\ieT'\~
DA TE : 'Z -'20 -\~el
PROJECT NO.· DRAWING NO
\
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I I •
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LEGENO
-$-Indicates Approximate. LOCQfioM Of Te.s+ lOoriM'3
BEN TON ENG 1 NEE R I' N' G, 1 N C •
SAN DIEGO, CALIFORNIA
LOCATlOt-J OF TEST 60R1N65
PItOPOSED 14 UNIT CONDOMINIUM
LOT 40 OF LA COST~ SOUTH UNIT NO.1
N/t..VAR.~P\ D~'\IE
CA~l.$e,~t], CALIFORN'~
SCALE : [":: lO·
DRAWN :l<,L.Greel1 C\i~,,~
DA TE : 'Z ~ZO -l'3el
PROJECT NO., DRAWING NO
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