HomeMy WebLinkAboutCT 73-33; LA COSTA SOUTH UNIT NO. 1; PRELIMINARY SOILS INVESTIGATION; 1968-03-08• C-r73--33· • r •
•
•
•
•
•
•
•
'.
BENTON ENGINEERING, IN~.
APPLIED SOIL MECHANICS -FOUNDATIONS
PHILIP HENKING ~ENTON
PRESIDENT· C!JVIL J;NGINEER
Rancho La Coda, Inc:
Rou te 1, Box 2550
Encinitas, California
6741 EL C;AJON BOULEV.ARD
SAN DIEGO, CALIFORNIA 92115
March 8, 1968 ~
Subject: Project No. 68-2-2C
Preliminary Soils Investigation
La Costa South Unit No.1
East of the Intersection of
Gentlemen:
La Costa Avenue and H Camino Real
SanDi ego County,. Ca I Hom ia
CONCLU5101'45
SAN DIEGO: 583·5654
LA MESA: 469·5654
RECEIVED
SEP 19 1913 ,
-Of CARLSBAD CiTY .' Department Engineenng .
It is conc!.uded from the field investigation and laboratory tests results that:
1. . Generally th~ existing natural sons which are to receive fi" and/or one and
two story residential dwellings are suitable tor the safe support of the proposed loads. How-
ever, the resui:ts of field densUy tests takfm in al'luvial soils existing in certain drainage
channels cUld low areas indicate that these, upper soi Is are relatively soft or loose and would
be considered unsuitable for the support of the proposed filled ground and dweUings. I,t is
recommended that these soft or loose soils be removed under the direction of the soils engineer
and the compac.ted filled ground placed on suitable supporting natural soils. Any loose or
soft natural soil~ existing in shallow cut areas should also be removed and replaced with fi lied
ground uniformly compacted to at least 90 percent of maximum dry density.
2. Calculations, based on the results of the shear tests performed on undisturbed
natural soils determined to be suitable for structural support, give a safe allowable bearing
pressure of at least 2000 pounds per square foot for one foot wide footings founded at a depth
of 1 foot below the undisturbed natural ground surface.
3. It is concluded from the resul·ts of the load-consolidation tests that the settle-
m~nt of a one. foot wide continuous footing loaded to 2000 pounds per square t09t and founded
on suitabl'e 'firm natural soils i$ estimated to be less than 1/8 inch.
4. It is concluded from the results of the expansion tests that the silty clay and
sandy clay soils encountered on the sHe would be considered to have sufficient expansion
••
•
•
•
•
•
•
•
•
•
Project ~~. 68-2-2C •
La Costa$outh Unit No. .
-2 .... • March 8, 1968
potentiar to require special design of foundations and slabs. Either during or upon 'com-
pletion of grading an inspection should be made of each lot to determine whether "expansive"
soils exist in the upper 3 feet below fininshed grade. Where expansive soils exist for thick-
nessesenough to cause adverse differential movementsrthen special recommendations will be
presented for the construction of houses on these "expansive II soils. Conv.entional type foot-
ings may be used where nonexpansive soils exist in the upper 3 feet below fin ished grade. It
may ,be. desirable to specify and provide for this condition during grading.
5. All of the soils may be satisfactori.ly compacted in the fill ar.eas and, when
compacted to at least 90 percent of maximum dry density, have a safe bearing capacity of
1510 pounds per square foot for one foot wide footings placed 1 foot below the compacted
ground surface • The settlement of a one foot wide continuous footing placed on fi IIsoi·ls
uniformly compacted to 90 percent of maximum dry density is estimated to be on the order of
,1/8 inch.
It is recommended that all soft or loose soils existing in proposed compacted
filled ground areas be removed as required by the solis engineer and the compacted filled
ground be placed on firm natural soils. Based on the results of the field investigat.ion and
laboratory tests the depths of this required removal would be 1.2, 4.5, 6.0 and 5.5 feet,
respectively I at Pits 1, 2, ·3 and 4.' .
Recommendations for the placemerit of fi lied ground are presented in the
. attached "Standard Specifications for Placement of Compacted Fiiled Ground,lI Appendix AA.
6. A. Preliminary plans indicate that cuts on the order of 50 to 60 feet in height are
to be ~ade on the south side of La Co~ta Avenve in the general vicinity of Borings 3, 4 and 5.
It is concl",ded from the field investigation and the test data that these cuts be made no steeper
than a slope ratio of 2 horizontal to 1 vertical. Relatively shallow cuts are indicated on the
lot areas and these may be excavated on a 1 1/2 horizontal to 1 ve.rtica·1 for heights not to
exceed 20 feet.
B. The fill soils, when uniformly compacted to at least 90 percent of maximum dry
density in accordance with the approved specifications, will be stahle with an adequate
factor of safety when constructed on a 1 1/2 horizontal to 1 vertical slope. The maximum
heights of fill slopes are estimated to be approximately 33 to 37 feet.
IfanysoiJ types are encountered during the grading operafion tha.t were not tested in this
investigation, additional laboratory tests wi H be cOllducted in order to determine their
physical characteristics, and supplemental reports and recommendations will automatically
become a part of the specifications. .
The data presented on the attached pages are a part of this report.
Resp~ctfu"y submitted,
<'BEN"J:OI'\l ENGiNEERING, INC.
By -R.C~
R; C. Remer
/,/
Reviewed f(y~. ~~"""'~_ ......... ~-=-=-~~ __
Distr:
BENTON ENGINEERING • .INC,.
( 4) Addressee
(2) Mcintire & Quiros, Inc.
Atten tion : , Mr. Gary Cumbe),
(1) Rick Engineering
•
•
•
••
•
•
•
•
•
•
•
Pr-o·ject No. 68-2-2C •
Lq Costa South Unit No.1
-3-• March. 8, 1968
DISCUSSION
A preliminary soils investigation has been completed on the proposed La Costa South Unit
No. 1 located east of the intersection of La Costa Ave,nue and EI Camino Real in San Diego
County, California. The objectives of the investigation were to determine the existing soil
con.di-tiOris and physicai prqperties of the soi/sin order that engineering recommendations
could be made for the grading .and construction of houses on' th is un it. In order to accompl ish
these. ob jectives, three borings were dri lied with a truck-mounted drill rig and seven pits
were excavated using a backhoe, field density tests were taken, undisturbed and loose bag
samples were obtained, and laboratory tests were performed on these samples.
The site is located on the Squth side of the. valley extending easterly from .the Batiquitos
Lagoon northeast of Encin'itas, Cal ifornia. The southerly portion of the site may be described
as gE!ntly rolling terrain while ·much of the north portion is located on the' steep sloping sides
of the valley. Much of the upper land has been cultivated.
The upper soils in the val'ley and lower slope areas in the north portion of the site are described
by the U.S. Department of Agriculture as Alviso loqm and Huerhuerq fine sandy loam. Th.e
major soil types encountered in the exploration borings and pits were silty sand, clayey scmd,
sandy clay, and silty clay. .
Field. Investigation
Three borings, Numbers 3, 4 and 5,' were drilled with a truck-mounted Fotary bucket-type
dti II rig and seven exploration. pits were excavated using a backhoe. The boring$ were drilled
during the same period as Borings 1 and 2 on La Costa Avenue between EI Camino Real and
La Costa South Un it No.1. The approximate locations of the borings and pits on La Costa
South Unit No.1 are shown on the attached Drawing No.1, entitled IILocation of Test Borings
Qnd :Exploration Pits! II The borings w~re drilled to depths. of 46 to 51 feet below the existing
ground surface and the dep.ths of the exploration pits varied from 4 to 15.5 feet. Acontinuous
log of the soils encountered was. recorded at the time of excavation and is shown in detai·1 on
DraWing Nos. 2 to 10, inclusive I each entitled "Summa~y Sheet. II
lhesQils were v.isually classified by field identification procedures in accordance with the
Unified Soil Classification Chart. A simplified description of this classification system is
presented in the attached Appendix A at the end of this report. .
Undisturbed samples were obtained in the borings at frequent intervals in the soils ahead of
the·drilling. The drop weight used for driving the sampling tube into the soils was the IIKellyll
bar of the dri II rig wh i ch we ighs 1623 pounds, and the average drop Was 12 inches. The
general procedures used in field sampling are described under "Sampling II in Appendix B.
In-place field density tests were taken in Exploration Pits 1, 2, 3 and 4, using the sand dis-
placemen.t method, in order to evaluate the suitability of the soils in these areas for the
supporf of fi lied ground. .
BENTON ENGINEERING. INC.
•
~' ~:
•
•
•
•
.,
Project No. 68-2-2C •
. La Costa South Unit No .. 1 .
-4-• March 8 I 1968
Lqboratorx Tes~
Laboratory tests were performed qn all undisturbed samples of the soils in order to determine
the dry density and moisture content. The results of these tests are presented on Drawing
Nos. 2 to 10, inclusive. Consolidation tests were performed on representative samples in
order to determine the load-se.ttlement characteristics of the soils. The results of these tests.
are presented on Drawing Nos. 11 and 12, each entitled "Consolidation Curves."
In addition to the above laboratory tests, expansion tests were performed on soFTie of the
clelyey soi·ls encountered to determine their volumetric change charqcteristics with chdl,1ge
in moisture content. The recorded expansions of the samples are presented as follows:
!
San Diego Coun ty Method
Percent Expansion Under Percent Expansion Under
Depth of UnH Load of 144 Pounds Un i t Load of 500 Pounds
Boring Sample Sample, Soil per Square Foot from Opti-per Square Foot from
No. No. in Feet Description mum Moisture to Saturation Air Dry to Saturation
3 7 35.0-35'.5 Silty clay '6.19
4 4 15.5-16.0 Silty clay 7.23
4 6 25.5-26.0 Clayey fine sand 1.27
5 6 20.0-20.5 Silty clay 7.15
3 Bag 1 2.0-3.0 Silty clay 7.30
Pit 5 Bag 1 1.0-2.0 Fine to medium 6.12
sandy clay
PitS Bag 2 4.0-5.0 Silty claY' 5.90
Direct shear tests were performed on saturated and drained samples in order to determine the
• minimum angle of intem.al friction and apparent coh.esion of the soils. The results of these tests
are presented in the following tabulation:
Normal Shearing • Load in Resistance
kips/sq ·ft Kips/sq ft
Boring 3, Sample 7 0.5 '1.26
Depth: 35.0-35.5 feet .2.0 2.06
• Boring 4, Sample 8 0.5 1.55
Depth: 35.5-36~O feet 1.0 2.69
2.0 5.07
Boring 4, Sample 11 0.5 1.08
Depth: 50.5-51.0 feet 1.0 2.24 • 2.0 3.22
* Indicates reduced value.
• BENTON ENGINEERING. INC.
Angle of
Internal
Fri ction
Degrees
Apparent
Cohesion
Ib/sq ft
28 1000
40* 400
40* 370
,I
•
~~. ~'
•
.,
•
•
•
•
•
•
•
•
Pro i~ct No. 68-2-2C • -5-
La Costa South Unit No.1 • March 8, 1968
Angle of
Normal Shearing Internal Apparent
Load in Resistance Friction Cohesion
kips/sq ft ' Kips/sq ft Degrees Ib/sq ft
Boring 5, Sample 5 0.5 1.07 22.5 860
Depth: 15.5-16.0 feet 1.0 1.45
2.0 1.69
Boring 5, Sample 11 0.5 2.65 40* 400*
Depth: 40.5-41.0 feet 1.0 3.34
2.0 5.45
Boring 3, Bag Sample 2** 0.5 0.82 ' 17.5 660
Depth: 6.0-7 .0 feet 1.0 1.08
2.0 1.30
Boring 5, Bqg Sample 1 ** 0.5 0.59 36 250
Depth: 38. O~39 .0 feet l.0 1.02
2.0 1.69
Pit 5, Bag Sample'2** 0.5 .2.76 14 1000*
Depth: 4.0-5.0 feet 1.0 2.34
2.0 3.14 "
Pit 6, Bag Sample 4** 0.5 0.43 33.3 100
Depth: 9.0-10.0 feet 1.0 0.92
2.0 1.41
* Ind i cates reduced va lue •
** Indicates test sample compacted to 90 percent of maximum dry density.
The general procedures 'used for the preceding laboratory tests are described briefly in
Appendix B.
Compaction tests were performed on representative samples of the sons to establish
compaction criteria. The soils were tested according to a modified A.S. T.M. D 1557-58T
method of compaction which uses 25 blows of a 10 pound hammer dropping 18 inches on each
of 5 layers in a 4 inch diameter 1/30 cubic foot mold. The results of the tests are presented
as follows:
Maximum "Optimum Mois-
Boring Bag Depth Soil Dry' Dens i ty tu re Con ten t
No. Sample in Feet Description Ib/cu ft % dry wt
3 1 2.0-3.0 Silty clay 114.8 14. 1
3 2 6.0-7.0 Silty clay 110.6 15.7
4 1 4.0-5.0 Silty fine sand 116.0 13.2
5 1 38.0-39.0 Silty fine sand 119.0 12.0
Continued on page six.
BENTON ENGINEERING, II",:.
"' I
•
~ J'~
•
•
•
•
•
•
•
•
•
•
Project No. 68-2-2C •
La Cos ta Sou th Un it No. 1
-6-• March 8, 1968
Maximum Optimum Mois-
Pit Bas Depth Soil Dry Density tu re Con ten.t
No • Sample in Feet Description Ib/cu ft % dry wt
1 1 2.0-2.5 Silty clay 118.0 13.6
2 2 4.0-4.5 Fine sandy clay 120.2 12.2
3 1 2.0-2.5 Clayey~ne to medium 128.0 8.4
sand
4 2.0-2.5 Clayey fine to medium 131.8 7.4
sand
5 1 1.0-2.0 Rne to medium sandy clay 125.0 10.5
5 2 4.0 .. 5.0 Silty clay 118.8 12. 1
6 2 .1.0-2.0 Silty fine sand 103.6 15.5
6 4 9.0-10.0 Silty fine sand 113.0 13.2
Atterberg. Limit tests were performed on a representative sample of the silty clay soil in
accordance with A.S . T.M. D 423-61 T and D 424-59. The results of these tests are presented
as follows:
Boring Sample Depth Liquid Plasticity Group
No. No. in Feet Soil Description Limit Index Symbol
5 5 15.5-16.0 Silty clay 58.7 32.6 CH
Unconfined compression tests were performed on representative sampl.es of the silty clay soils
and the resul.ts are presented below:
Cohesion
Ib/sq ft
Boring Sample Depth (1/2 Un con fined
No. No. in Feet Compressive Strength)
3 10 40.5-41.0 1380
5 7 20.5-21.0 670
5 13 45.5-46.0 4650
Using the lower values of internal angle of friction and apparent coh eSI 00 , and the Terzaghi
Formula for local shear failure, the safe allowable bearing pressures for the soils are deter-
mined as follows:
Local Shear Formula: Q I = 2/3 c N I + D f N I + BN I c y q y y
Assumptions:
Continued on page seven
(1) Continuous footing 1 foot wide =2B
(2) Depth of footing = 1 foot = Df
BENTON ENGINEERING. INC.
• Project No. 6S-2-2C •
La Costa South Unit No. ,.,
-7-•• March 8 I 1968
~. Undisturbed natural soils
~
•
•
•
•
•
'.
•
•
•
•
4> :: 22.50
N'c ~ .13.5
c = 860:lb/sq ft
N'q::: 6.0
y = 120 Ib/cu ft
N'y = 3.3 -
.QI = (2/3 x 860 x 13 •. 5 + 120 x 1 x 6.0 + 120 x 0.5 x3.3) = 8,,660 Ib/sq ft
Q' Safe = QI--;:-3 {Factor of Safety} = 2,880 Ib/sq ft
Filisoil~ com~cted to 900k of maximum dry density
ct> = 330
N'c21.5
c = 100 Ib/sq ft
N'q=12.0
y :; 120 Ib/cu ft
N 1
y = 7.5
Q';:(2/3x 100x2i.5+120x 1x 12.0+120xO.5x7.5}=3323Ib/sq ft
QI Safe = Q'-;--2.2 (Factor of Safety) = 1510 Ib/sq ft
BENTON ENGINEERING. IN(:.
•
'" .-
•
•
•
•
•
•
•
•
w
::E <I: Z
al' o ..,
'0
z wO:: .... w ::t:ti:i a.. co
.... w ::E::E a..u. <I:=> w VIZ 0
SUMMARY SHEET
BORING NO, 3
ELEVATION 162' *
SILTY FINE
SAND
6-tz:::=:~ 0\ ive-green, Moist, Very Firm,
12
Dipat5.5' =6° to N 3° W
Light Olive-green
Thin Cemented Sandstone
Lens
Yellow-gray , Moist, Very Firm,
Lenses of Highly Cemented
Sandstone
Light Olive-green
SILTY CLAY
SILTY
FINE SAND
o o
Con tinued On Drawing No.3
-Indicates L09seBag Samp:le
-Indicates Undisturbed Drive Sample
9 .7 11.9 122.2
19.5 17.9 112 .. 2
32 .5 13.4 120. 1
32.5 10.0123.0
48. 1 1 1.9 121. 1
* -The elevations presented for Borings 3, 4 and 5 were furnished
PROJECT NO.
68-2-2C
by Rancho La Costa
BENTON ENGINEERING, INC.
DRAWING NO.
2
•
,/
•
•
•
•
•
•
•
•
-:E B en
Q)
;:) c Q) > <:(
.e (9
u'
.3
w :E « z
I:Q o ...,
!:;
:r:ti:i I-w Cl.u.. w 0
SUMMARY SHEET
BORING NO. 3 (Cont.)
r-3 \,L-/LV Light Olive-green, Moist,SILTY 25 0 17 Q 109.1i
t:::Z,..oL::I\Very Firm, Dip = 2° to N 3° W FINE SAND / . .u· • .J L-~~~~~~ ________ ~~~~~~ __ ~
32
18.0 111.2
29.2
SILTY CLAY
4o-~ 12.7 121.6
. Yellow Brown
AA. Some Cemen ted Lenses
Cemen~d Sands~t~oo!,~e ____ -+ __ ~~_=-~ ______ ~ ___ +-__ +-__ ~ __ ~ __ -4
AA '., .... ::.::" Yellow-brown, Slightly Moist, CEMENTED
Very Firm SANDStONE
PROJECT NO.
68-2-2C BENTON ENGINEERING, INC.
DRAWING NO.
3
•
;,
•
•
•
•
•
•
•
•
•
•
-:5
5 VL
:2 a u
0 ....J
w
:E < Z
IX! o ....
SUMMARY SHEET ~ wa:: ..... w .... e..1X! ::t:w ~~ ,BORING NO. 4 I""w e..u.. <=> w VIZ 128,1 0 elEVATION
, Very Moist,
Soft, Topsoi I SILTY CLAY
2 Yellow-brown, Moist"
Medi urn 'Fi rm
Yellow-brown., Moist, Medium
Firm, Sil ty Clay.
Lenses at 5.0 Feet SilTY
FINE SAND
CI~y.!y Fi~e S~~d Le,~_s.~.s,
Light Olive"11reen, Moist,
Very Firm'
Dip = 50 to N200 W
12
SIL ty CLAY
]4
16
18
t, Very' CLAYEY FINE
SAND
st, Very
Th in Sil ty Clay Lens
SILty
FINE SAND
Continued on Drawing No.5
PROJECT NO.
68-2 ",,2 C BENTON ENGIN'EERING, INC.
>-(!) ~ wI-ac: u.. w"-... c~;: Z VI w' e.. ........ >-
w 52 WVlac: U::(5o > ~ u.. ~<;l! a:: 0
13..0 9.4
21.1 15.4
32.5 16.4
39.0 13
74.7 14.7
>-I-I-w~' Vi u.. Uu.. Z . a:: Z . w => o~ «0 W,""VI
>-vi ::t:~VI VIVIe.. a:: IX! w_ o .... a::~
13. 1
10.9
15.0
1.1
119.
DRAWING NO.
4
•
•
•
•
•
•
•
•
•
•
•
-:E.
B
V)
.E
8 u
0 -'
w
:E « z
IX! o ....,
Z
:du I-w Q..u.. w
Cl
wO:: .... w·
Q.I:O :E:E «:J II'IZ
SUMMARY SHEET
BORING NO, 4 (Coot.)
Yellow-...... · .... wn , Moi~t( Very
Firm
. Gray-brown, Moist; Very
Compact
Thin Silty Clay Lenses
Yellow-brown i Occasional
Coarse Grains of Sand
SILTY FINE
SAND
65.0
50.0 7.1118.6
SLIGHTLY SIL TY 50.0 10.8 127.0
FINE TO MEDIUM
SAND
50.0 9.2122.0
PROJECT NO. DRAWING NO.
5 68-2-2C BENTON ENGINEERING, INC.
•
I·
•
•
•
•
•
•
•
•
•
•
-:E => '0 V')
.E
('8
c
. w
~ « Z
ca o ...,
Z w,'o:: ..... w
:rdjj c...ca
I-w ~~ c...LL. ~::::> w VIZ £:)
I SUMMARY SHEET
BORING NO.---::5=---_
ELEVATION 19]1
Mois t, Soft,
Olive-green, Moist, Medium
Firm
Streak of White, Very Firm
Light 01 ive-green, Stre.aks of
White
Thin Silty Fine Sand
Lens
Yellow-brown, Moist, Very Rrm,
Sligbtly Silty Fine to Medium
Sand Lenses and Some Coarse
Sqnd Grains Below 24.0 Feet
Thin Silty Clay Lenses
Cemented Sandstone Lenses
SILTY CLAY
SILTY
FINE SAND
. Continued on Drawiil.g No.7
PROJECT NO.
68-2-2C BENTON ENGINEERING, INC.
14.6 19.6 to7. 1
16.220.9 09.8
11.4 17.3 06.0
17.5 . 11.8
19 .. 5
75.011.1 19.6
DRAWING NO.
6
•
•
•
•
•
•
•
•
•
•
•
-:E
:;)
0 V')
.e ~.' u
.9
w ~ 4
co o ...,
~ wa:: .... ,w :d~ . c..co ~~ I-w o.u.. <=> W C VlZ
SUMMARY SHEET
BORING NO.
t, Very
5 (Cont.)
SIL IY FINE SAND
(Continued)
ive-green, Moist, ery Firm,.
w.:..::z.~ Dip =20 to N40° E SIL TY CLAY
Gray-brown, Moist; Very
Compact, Some Coarse
Send Grains
PROJECT NO.
68-2-2C BENTON
SIL TY FINE TO
MEDIUM SAND
ENGINEERING, ,INC.
>->-C> I"-W"': I-I-w·· a:: u.. -u.. uti: w ........ c~:: Vl . Z . a::z z Vl w => «0 w c.. 1->-c~ Vla:: WI-Vl W ~ u..Oc >-vi ::t:Vl -..,... > . Vl-Vl -I-::E~ a:: co Vlo. a:: u.. C .... w_
a::~ C
32.5 11.7 . 19. 1
62.5 10.2 22. 1
57.5 8.9 109.9 I
58.3 13 ~ 1 120.2
24.7 20.2 .8
DRAWING NO.
7
•
•
•
•
•
•
•
•
•
•
•
w
:E « z
I:Q o ..,
>-. >-. z ~ wtc SUMMARY SHEET ~ I:i: w~!:: t: ~...: 0
:x: I-·it ~ ~ ~ e ~:t ~':l 5 z ~ t;i= ~ Ww c C PIT NO 1 w C. ...I I->-we U < 0:,-: U ii:u..::;:~ .............. 10....-0.. W i2 !:!:!!aCII: ....... tii~~-
W Vi Z > u.. oe >-vi ~ -VI ~ a.:
:£ OU=I~~G~ .... ~ryr:_~~!r~own~'~~ME~oL,~Ei:'Vlt:~T~ l'Ooos~N;e,~~'~612~ c· O~l'A~~~Y'~IE:Y~F~11 N~I~ET~0[=~-=-=tL:-'t=-=-~=-'i)'::~o"=-~=-=-~='f=-~=-9~-+--~-P=)-f 5 _. \Some Roots, Recent Alluvium MEDIUM SAND I .
"> 2-mll Gray-blac'k, Very Moist, Soft, 15.1102.1 86.7
:..; Moist, .Firm Below 102 Feet, « . Very Firm at 4.0 Feet T A
SIL TY CLAY
PIT NO. 2 ----------
ELEVATION 88.0'
U OU=='~sG~'lrci~y-:-~'I,~ckk-;NM~OiS:, SSOiof~t., -,--iff-I III
-lome 'Roots .
§ 2 ffii 1 Light Gray-brown, Very Moist, FINE SANDY' 17.2 92.0
.~ Soft, Sca.ttered Chunks of Gray CLA Y
. « 4~7?' .~ Silty Clay
~ 5· ,., . .iSh t Brown, Moi. t, Firm SIL TY FINE SAND
PIT NO. 3 ----
ELEVA TI ON 34.0'
IT o· ~7. y: ! r Light Brown, Moist, Loose
. i), •• \Brown, Very Moist, Soft .~ ZL\J 1 I Brown, Ve ty Moist, Loose,
> -f--..,----:1 [-=
I=< 4-;2\12 Scattered Gravel and Pea Gravel
11 .-:: at3.0Feet,20-30%PeaGravel
il. ~ ~:I,' J::!ncLG rave I Be I ow 4 .0 ~eet
',nl3 Dark Brown, Very Moist, Medium
-.'~. Firm, Very Firm Below 7.0 Feet
0. v
o I
Brown, Very Moist, Very Firm
S·IL TY FINE SAND
SILTY CLAY . /
CLAYEY FINE TO
MEDIUM SAND
FINE SANDY
CLAY
(MerSJes)
SILTY CLAY
6 -Indi.cates location of in-place field dens·jty test o -Indicates loose pag sample.
12.6 89.5
14.0 100.7
15. 1 105.3
14.7 110.7
* -The elevations shown for the exploration pits were de·termirted by
interpolating between the contours shown on the grading plans
prepared by Mcintire & Ql!iros, Inc.
76.5
74.4
78.7
82.4
PROJECT NO. DRAWING NO.
68-2-2C BENTON ENGINEERING, INC. 8
•
•
•
•
•
•
•
•
•
•
-£
is
V)
.E ~ U
C ...J
w
~ « z.
to o ...,
~
:::dii .... w c..u.. w o
SUMMARY SHEET
PIT NO. --,-,4,--_
ELEVATION 34.0'
tD~ ~~ w' 9-IX u.. w .... Vi u.. u~1t-t=: Z ~ I~~ ~ z :;) IX z olz 0 w c.. .... >-:::: u «~~ «
-.... ~·olXtO wc.. ~u.. ""0 .... 1XS2
~ ~ 6~ >-:i ~~I11~~'8o..
~·OO~~~~~j.~B-ro-w-n-,\V'e-ry-."Mo~i:s~t~,~~[oo~se-,~--rC~L~A~\Y~E:Y~F~IN7.E~~T·O~~--~--~---r---r~~
-... :: Roots MEDIUM SAND
2-~ 11 Dark Brown, Very Moist, I CLAYEY FINE TO
-;-Loose . MEDIUM SAND
4-::: .,,'~' Dark Brown, Very Moist, Loose, CLAYEY FIN:E TO
~~i :".~ 70"80010 Pea Gravel and Gravel MEDIUM SANDY
i.lX,i'r" Below 3 Feet GRAVEL
t-.'"' Brown, Very Moist, Very Firm SILTYC~AY
\ I
PIT NO. 5 ---
ELEVATION 76.0'
o· 17.."-',, SILTY ~:..."Q,~ Dark Browr.J Mol t I Loose,
[i.;o F,\TopsOil
2 1 Brown, Mois t, Fi rm, Scattered
~INE SAND I
-Gravel,. Some Mediurh to Coarse
A . Sand Grains; Flecks of Rust 'and
~21B White at 1.0 Foot, Slightly
-Moist and Very Firm Below 2.0
6 Feet, Some Gravel Below 3.0
_J!o ........ ~. Feet -
Q
~INE TO MEDIUM
SANDY CLAY
PROJECT NO.
68-2':'2C BENTON ENGINEERING, INC.
13.6106.1 80.7
DRAWING NO.
9
•
•
•
•
•
•
•
•
•
•
•
i:.
6'
V')
.2
8 u
o· ...J~
w :e < z
a:I Q
~ wO: ...IW . 1-Q..a:I Xw :e:e I-W Q..u.. <=> W VIZ 0
1
SUMMARY SHEET
PIT NO. 6
ELEVATION 248.01
rown, Moist,
CldyBinder -----"-
Light Brown, Moist, Very.
r
Compact, Fractured, Gray
Streaks With Rust and Yellow
Light Brown-gtaYr Moist, Very
. SILTY
FINE SAND
Compact, lightly Cemented SLl-GHTL Y SILTY
S i I ty Fine Sand Lenses
Light Brown, Moist, Very Firm
Gray Slightly Silty Fine Sand
Lenses With Rust Streaks
PIT NO. 7
FINE SAND
SILTY
FINESAND
ELEVATION 242.01
Light Brown-gray, Moistr ' rm,
Fractured, Very Rrm Below 1.0
Foot, Yellow Streaks at 2.0 Feet,
Rust Streaks at 3.0 Feet
Cemented Sandstone
Light Brown, Moist I Very Firm,
Gray, Slightly Silty Fine Sand
Lenses With Rust Streaks
SIL TY FINE
SAND
SLIGHTLY SILTY
FINE SAND
SILTY FINE
SAND
PROJECT NO.
68-2-2C BENTON ENGINE~RING, INC.
>-C) ..... W...: 0: u.. o~;: ~W ........
Z VI Q.. ...11->-W WVlo: W ~ 0.0 ~ ...: :e~ 0: u..
0
>-I-I-w"'; Vi u.. Uu.. Z • 0: Z • w :') «0 o~ WI-VI XVi ........ >-.,; VI-VI
0: a:I VlQ..
Q ...I
w_
o:~
DRAWING NO.
10
•
•
•
•
•
•
• .
0 7
0l-
c ::J
..s: • 01-:> 0 V)I
.12 1
lS U
0 ...J •
• w ~
-{!;
Zf
Iltt
0 ~ •
(I)
(I)
LIJ Z
:II::
0
J:
I-
LIJ
..J Do 2
oe(
(I)
IL
0
I-Z LIJ () a: LIJ Do
z
2 I-oe( e ..J 0 (I) z 0 0
CONSOLIDATION CURVES
LOAD IN KIPS PER SQUARE FOOT
. . 04 06 08 10 -. 2 4
+3 ~
""'" ~
~ '" +2 '" "-I"-""
+1 ~." ~ .~ ~
'\1
0 -r--f--:--I-:--< :'---------.
1
0
1
I I I i . , , , I
(~ r------I
2
~ --~ .'--------------
,-~----.
I ,
I
I I
.......... .....------1-_ r--""'-( , -----' ~ ~I ----
I -------I I--. ,
I --~ 1 I
o Indicates percent consol idation at field moisture
G Indi cates percent consolidati on after saturati on
PROJECT NO.,
68-2-2C BENTON ENGINEERING, INC.
6 8 10 16
Boring 3
_ Bag 1
DeQth2-3'
Remolded to 900/0
of Maximum Dry
Density
. -
i 1
I
Boring 4
Bag 1
Depth 4-5'
Remolded to 900/0:-
of Maximum Dry
Densi'ty
I l
..
I
DRAWING NO.
11
•
CONSOLIDATION CURVES
• LOAD IN KIPS PER SQUARE FOOT
04 06 08 10 2 4 6 8 10 16
I
Boring 5
~ B.ag 1
-------Deoth 38-39'
• -----Remolded to 90°1c ---....., of Maximum Dry ~ Densih,
~
-r--~ ---::::::-..... • 2
II)
U)
LLI Z ~
0 • :x: t-
O
LLI ..J Q.
2 e(
II)
• IL 0
I-Z LLI
0 ~
).,..-I
Pit No.6
r---I Bag 4 .
~ ~----Deoth 9-101
....:....... ---...,... -......" Remolded to 9001c. ---~ ----of Maximllm Dry
""-r-Densit'> .
... -----~ ~ . .' ...-LLI Q. • .
0
Z z 2 .... g
:5 l-e(
9 ...c' ..J "-0 :J II) 0 z • lI) 0
E 0
()
U
0 .....I
•
I
j
I
i I
I
I
1
! I
I
I I I'
I I I
r I -t ,
I I I
• w
I
I II I I
:\It,
<:t
2: o Indicates percent consol idqtion at field moisture
«In
0
I ~ Indicates percent consol idati on after saturQti on
"") . •
6S ... 2-2C 12
PROJECT NO. OR'AWING NO.
INC. ENGINEERING 1 BENTON
•
•
•
•
•
•
•
•
•
•
•
PHILIP HENKING,BENTON
PRESIDENT'· CIVIL ENGINEER
• •
BENTON ENGINEERIN'G. INC.
APPLIED SOIL MECHAN'ICS -FOUNDATIONS
6717 CONVOY COURT
SAN [)IEGO, CALIFORNIA 92111
APPENDIX AA
STANDARD SPECIFICATIONS FOR PLACEMENT
OF COMPACTED FILLED GROUND
TELEPHONE (714),565.1955
1. General Description. The objective is to obtain uniformity and adequate internalstrengt,h
in fi.lled ground by proven engineering procedures'and tests so that the proposedstruc;tures m~y: be safely supported. The procedures inc lude 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 th~
atcepted plans. ' '
The owner shall employ a qual ified soi Is engineer to inspect c;md test the fi'l1~d ground as
'placed to'verify the uniformity of compaction'of filled ground to the ,specified 90 percent
'of maximum dry density. The soils engineer shall advise the owner and grading contractor
immediQtely if any unsatisfactory conditions are observed to exist,and shall have the
authority to re ject the compacted fi lied grou'nd until such time that corrective measures
are taken necessary to comply with the specifications. It shall be the so,le responsibi lity
of the grading contractor to achieve the specified degree of compaction.
2.' 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 b~ corrected by draining or '
removal, or both.
(b) The natural ground which is determined to be satisfactory for the support of the filled
ground sho'll then be plowed or scarified to q, depth of af I~ast six inc,hes (6"), ane;!
unti I the surface is free from ruts, hummocks, or other uneven features which would
tend to pr,event uniform compaction by the equipment to be used.
(c) Where fills are made on hillsides o,r exposed slope areas, greater than 10 percent,
horizontal benches shall be cut into firm undisturbed natlJrc;:t/ ground in order to prov'ide
both lat,eral and vertical stability. This is topr.ovide a horizontal base so that each
layer is 'p laced 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 qt t,he elevo-
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 wiIJ
vary with the soil conditions and the steepness of slqpe.
•
•
•
•
•
• • APPENDIX AA
-2-
(d) After the, nattiral ground has been prepared, it shall then be brough-t fo the prop'at mois-
ture content and compacted to not ress than' nin~ty percent' of maximum densHy in
accordance with'A.S. T.M. D-1557-66T method that_ uses 25, blows ,of a 1Q pound hammer
falling from 18 inches on each of 5 layers in a 4" diameter cylindrical mold of a 1/30th
cubic foot volume. -
3. Materials and Special Requirements. The fill soils shall cpnsistof select materials so graded
that at least 40 percent of the material passes a No.4 sieve. This may be op-to[ned from
the excavation of banks, borrow pits of any other approved sources arid by mixlngsofls from
one or more sources. The material uses shall be free from veg_etQble -matter ,and oJher de-
leterious substances, and shall not contain rocks or lumps of g-reater than 6 Inches in diameter.
If excessive vegetation, rocks, or soils with inadequate streng-th or other unacc;eptable physicql
characteristics are encountered, these shall be disposed of in waste areas as shown onfhe
plans or as directed by the soils engineer. If during gracnng operations, soils-not encountered
and tested in the preliminary investigation are found, tests on these soils shall be performed to
determine their physical characteristics. Any special treatment recommended in the preliminary
or subsequent soil reports not covered herein shall become an addendum to these specifications.
The testing and specifications for the compaction of subgrade , subbase , <;Itid bas~ materials for
roads" streets, highways, or other public property or rights-of-way shall be in accordance -
with those-of the governmental agency having jurisdiction.
• 4. Placing, Spreading, and Compacting Fill Materials.
•
•
•
•
•
(a) The suitable fill material shall be placed in layers which, when compacted shall not.
exceed six inches (6"). Each layer shall be spread evenly and shall-be throug-hly
mi:><ed during the spreading to insure uniformity of materiell and moisture in each layer.
(b) When the moisture content of the fill material is below that specified by the soils engineer;
wgter shall be added unti I the moisture content is near optimum as speciJied by the -
soils engineer to assure thorough bonding during the compactlng process.
(c) When the moisture content of the fi" material is above that specified by the soils
engineer, the fill material shall be aerated by blading and scari'fying or other satis-
factory methods unti I the moisture content is near optimum as specified by the soils
engineer. -
(d) After each layer has been placed, mixed and spread evenly, it shall be thoroughly
-compacted to not less than ninety percent 0.£ maximum density in acc¢rdcmce with
A. S. T.M. 0-1557-66 T modified as described in 2 (d) above. Compaction shall be-
accomplished with sheepsfoot rollers, multiple-wheel pneumatic-tired rollers,_ or other
approved types of compaction equipment, such as vibratory eqpipment .that is specially
designed for certain soil types. Rollers shall be of such design -that they wHI be able
BENTON ENGINEERING, INC.
•
•
•
•
•
•
•
•
•
•
•
• • APPENDIX AA
-3-
. to compact the fI II material to the specified densl·ty. Rolling shal·1 be accomplished
while the fill material is at the specified moisture content. Rolling of each layer shall.
be contfnuous over Its entire area and the roller shall make sufficient trl,ps to insure
that the desired density has been obtaIned. Thet entire areas to be filled shall be
compacted •
(e) Fill slopes shall be compacted by means of sheepsfoot rollers or ()fher su.itabl"e equipment.
Compactfng operations shall be continued until the slopes are stable but nof too dense
for planting and unti I there is no appreciable amount of loose soil on the slopes.
Compacting of the slopes shall be accomplished by backrolling the s'lopes In rncr'ements
of 3 to 5 feet in elevation gain or by other methods producing satisfactory results.
(f) Field density tests shall be taken by the soffs engineer for approxlmatelyeach 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 elevattongaln if
required by the soils engineer. The location of the tes'ts in plan shall ,be so spaced to
give the best possible coverage and shall be ta'ken no farther apart than 100 feet • Tests
shall be taken on corner and terrace lots for each two feet in elevaflon gai·n. The soils
engineer may 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 com-
pacted material below the disturbed surface. No additional layers of fill shall be spread
untn the field density tests indica.te that the specified density has been obtained.
(g) The fill operation shall be .continued in six 'Inch (6") compacted layers, as specified
above, until the fill has been brought to the fln.tshed slopes and grades as, shown on
the accep.ted plans.
Q,
. 5. Inspection. Sufficient Inspection by the soils engineer shall·be maintained during the
fillIng and compacting operations so that he can certify" that the fill was constructed in
accordance with the accepted specifications. .
6. SeaSonal limits. No fill material shall be placed, spread, or rolled if weather co.nditi()ns
Increase ffle moisture content above permisSible limits. When the work Is tnterrup~dby .
rain, fill operations shall not be resumed until field tests by the soils engineer Indicate thQt
the moisture content and density of the fill are as previously specified.
,7. Limltfng Values of Nonexpansive Soils. Those solis that expand 2.5 percent or less from
air dry to saturatfon under a unit load of 500 pounds per square foot are considered to be
nonexpanslve.
8. All recommendations presented in the "Conclusions II section of the attached report are a
part of these specifications .
)r
BENTON ENGINEERING. INC.
,e
•
•
•
•
•
•
•
•
•
•
• • BENTON ENG-INEERING, -INC.
APPLIJ1:D SOIL MECHANICS -FOUNDATI0!'lS
6717 CONVOY COURT
SAN DIEGO. CALIFOI'!NIA 92111
PHILIP HENKING BENTON
PRESIDENT· CIV!L ENGINEER
APPENDIX A
TELEPHONE (714.) 5615·191515
Unified Soi I Classification Charf*
SOIL DESCRIPTION
I. COARSE GRAI NED, More than half of
materi.al is larger than No. 200 sieve
size. **
GRAVELS C LEAN GRAVE LS
More than half of
GROUP
SYMBOL
GW
coarse fraction is GP
larger t·han No. 4
sieve size .but smaller GRAVELS WITH FINES GM
than 3 inches (Appreciable amount
of fines) GC
SAND'S C LEAN SANDS
More· thahhalf of
coarse fraction is
smaller than No.4
sieve size SANDS WITH FINES
(Appreciable amount
of fines)
II. FINE GRAINED, More than half of
material is smaller than No. 200
sieve size. ** SILTS AND CLAYS
Liquid Limit
Less than 50
SILTS AND CLAYS
Liquid Limit
Greater than 50
11'1. HIGHLY ORGANIC SOILS
SW
SP
SM
SC
ML
CL
Ol
MH
CH
OH
PT
TYPICAL
NAMES
Well graded gravels, gravel-sand mixtures,
I ittle or no fi.nes.
Poorly graded gravels_, aravel-sand
m.ixt.ures, little or no fines.
Silty gravels, poorly groded gravEd-
sand-silt mixtures.
Clayey gravels, poorly graded gravel-
sand-clay mixtures.
Well graded sand, gravelly sands, little
or no fines.
Poorly graded sands, gtavelly san9s,
I·ittle or no fines.
Snty sands, poorly graded sand-silt
mixtures.
'Clayey ·sands, poorly graded sand-clay
mixtures.
Inorganic -si'lts and very fine ~ands! rock
flour, sandy silt or clayey-silt-sand
mixtureswit-h slight plasticity •
. Inorganic clays of low to .medium plas-
ticity, gravelly clays, sandy clays,
silty clays, lean clays.
Organic sil.ts ahd organic silty-clays of
low plasticity.
'Inorganic silts, rriicaceousor diatomaceol)s
fine sandy or si Ity soils; elastic sihs.
Inorgani9 clays of high pl·asticity, .fat
clays.
Orgc;mic clays or me~ilJm to high·
plasticity
Peat and other highly orgqnic-soils.
*. Adopted by the Corps of Engineers and Bureau of Reclamation in January, '1952.
**-All sieve sizes on this chart are U. S. Standard.
•
•
•
•
.'
•
•
PHILIP HENKING'BENTON
PRESIDENT· CIVIL ENGINEER
Sampl ing
• • BENTON ENGINEERING, INC.
APPLIED SOIL MECHANICS -FOUNI;lATIONS
6717 CONVOY COURT
SAN DIEGO, CALIFORNIA 92111
APPENDIX B
TELEPHONE (714) 565.1955
\-, The undisturbed seil samples are .obtained by fercing a special sampling tube in'tc .the
undisturbed sei Is at the bettem .of the bering, at frequent intervals belew the greund surface.
Tne sampling tube censists .of a steel barrel 3.0 inches .outside diameter, with a special cuning
tip en .one end and a deuble ball valve en the ether, and with a lining .of twelve thin brass
rings, each .one inch leng by 2.42 inches inside diqmeter. The sampler., cennected te a twelve
inch leng waste.barrel, is either pushed .or driven appreximately 18 inch'es inte the seil and a
six inch sectien .of the center pertien .of the sample is -taken for .Iaberatery 'tests, the soil b~ing
still cenfined .in the brass rings, after extractien frem the sampler tube. The samples are taken
te the laberatery in clese fitting waterpreef centainers in .order te retain the {ield meisture until
cempletien .of the tests. The driving energy is calculated as the average energy in feet-kips
'required-te ferce the sampling tube threugh .one feet .of seil· at the depth CIt which the sample is
.obtained. .
Shear Tests
The shear tests are run using a direct shear machine .of the strain centrel typE:) in which
the rate .of defermatien is appreximately 0.05 ·inch per minute. The machine is se designed that
the tests are made witheut remeving the samples frem the brass I·iner dngs in which thE:)Y are
secured. Each sample is sheared under a nermal lead equivalent tethe weight .of the scil abeve
the peint .of sampling. In seme instances, samples are sheared under varicus nermal 'loads in-.
.order te .obtain the internal angle .of frictien and c'ohesien~ Where cens'idered necessary, samples
are satur9ted and drained befere shearing in .order te simulate extreme field meisture cenditicns.
Ce'nselidation Tests
• The apparatus used fcr the censelidatten .tests is designed te receive .one .of the .one inch
high rings .of soil as it cemes frem the field. leads-are applied in several increments to the upper
surface .of the test specimen arid the resulting defer.mations are recerded at selected time intervals
fcr each inc-rement. Generally, each increment .of lead is maintained en the sample until the rate
.of deformaticn is ~qual te .or less than 1/10000 inch per heur. Pcreus stenes are placed in ccntact
• with the tcp and bettem .of each specimen te permit the ready additien .or release .of water.
•
•
Expqnsien Tests
One inch high samples cenfined in the brass rings are permitted to air dry at 105° F fcr
.gt least 48 heurs prier tc placing inte the expansicn awparatus. A unit Icad .of 500 pcunds per
square foct is then applied tc the upper percus stcne in ccntact with the.top of each sample-•. Water
is permitted tc ccntact beth the tcp and bottem of eCich sample tbrcugh pcrcus stcnes. Ccntinucus _ .
cbservatiens are made until dewnward mcvement stops. The. dial readinQ is reccrdedand expansicn
.is reccrded until the rate .of upward mevement is less than 1/1 0000 inch per heur. _
'.
•
. ,
I
I , , • ! ' I
•
•
•
BENTON ENGI~EERING, INC.
APPLIED SOIL MECHANICS -FOUNDATIONS
6741 EL CAJON BOUL:EVARD ,
SAN DIEGO, CALIFORNIA '92115
PHILIP HENKING EiENTON
PRESIDENT -CIVIL EN"INEER June 23, 1969
Rancho La Costa; Inc.
Route I, -Box 2550
Encinitas, California 92024
Subject:
Gentlemen:
Project No. 68-11-230
Fi nalReport on
Compacted Filled GrQund
La Costa South Unit No.1
Rancho La Costa, California
SAN ,DIEGO: 583-5654
LA: MESA: ,469-5654
This is to report the results of tests and observations made in order to inspect the ,compaction ,of
filled grol,lnd placed on certain areas of Lots I, 3 to 7, inclusive, 14 to 25, inclusive, 34 to 39,
.inclusive, 43 to 46, i'nc!usive, 54 to 58, inclusive, 62 to 72, inclusive, 82, 83, 84, 86, 87, 89,
90, 110 to 120, inclusive, 122, 123, 131, ,132, 151 to 154, inclusive, 166 to 1/'7, Inclusive,
181 to 184, inclusive, and Portions of La Costa Avenue, Navarra Drive, Viejo Castilla Way, .
Nuevo Castilla Way, Sevilla Way; Levante Street, Galicia Way, and La Coruna Place, LaCosta
SQuth Unit No.1, Rancho La Costa, California. The fills Were placed duri~ the periods'
between February' 4, 1969 and May 2; 1969.
The approximate areas and depths of filled ground placed under our inspection in accordance
with the approved specifications are shown on the attached Dtawi~ No. I, entitled "location
of Compacted Filled Ground. II The gradi:rlJ plan used for the placement of filled ground was
prepared by Mcintire & Quiros,lne. dated January, 1968.
The approximate loca'tions at which the tests were taken arn:! the final test resul ts are presented
on page Nos. 4 to .19, inclusive, under the "Table of Test Results. II The laboratory determina-
tic;ms of the maximum dry densities and optimum moisture contents of' the major fill materials
are presented on page No. 20, unoer the IILaboratory Test Resul ts. ,I Some of the maximum dry
densities shown in the "Tableof Test Results" were combinations of these. The tests we.re taken
duril'll the weekly per.iods indicated below:
Test Number
1 to .• 8, Inclusive
9 to 29, inc'lusive
30 to 37, inclusive
38 to 89, inclusive
90 to 139, inclusive
140 to 191, inclusive
192 to 257, inclusive
Conti nued on page two.
Week Ending
February 8, 1-969
February 15 r 1969
February 22, 1969
March 8, 1969
March IS, 1969
March 22, 1969
March 29,1969
•
•
•
•
• •
•
-.
•
•
Project No. 68-11-230 1.
La Costa South Unit No.
-2-• June 23! 1969
Test Number
258 to 352, inclusive
353 to 433, inclusive
434 to 461, inclusive
462 to 485, inclusive
486 to 506, inclusive
Week Endirg
Apri-I 5, 1969
Apri I 12, 1969
Apri I 19, 1969
April 26, 1969
May 3, 1969
The final results of tests and observations indicate that the compacted filled ground has been
placed at 90 percent of the maximum dry density or greater. It has been determtned thot the
fill ",aterials/compC:Icted to 90 percent of the maximum dry density, have a safe beari~ value
of ~t least 1510 ·pounds per square foot for one foot wide continuous footirgsfounded at a
minimum depth and placed five feet or more Inside the top of compacted filled ground sloPes.
If f06tlrgs are placed closer to the exposed slopes than 5 feet inside the top of compacted filled
grOllnd slopes, these should be deepened one foot below a 1 1/2 horizontal to 1 vertical line
proiected outward and downward fror:n a point ~ feet horizontally inside the top of compacted
filled ground slopes. Tests indicate that the compacted filled ground is adequate to satisfactorily
support the proposed one and two story wood frame dwellir'Gs without detrimental settlements.
In our report of the original investigation conducted a-t this subdivision, {Project No. 68-2"'2C
dated March 8, 1968), we stared that some silty clay and sandy clay solis had been found on
the sHe that v..re expansive, and we recommendf;ld that each lot be inspected durl~ or after
gradl.rg to determlne_ those lots In which such expansive soils exist within the upper 3.0 feet.
This has been done, and the folJowirg lots have been found to contain potentially expansive
soils within the upper 3.0 feet.
Lot Nos. 1 to 81 , inclusive
Lot Nos. 97 to 109, inc1usive
Lot Nos. 170 to 184, inclusive
It is recommended that the followill:) special design precautions be taken for the houses to be
constructed on the above-listed lots:
1.
2.
3.
IsolClted interior piers should not be used. Continuous footings should be used
throughout, and these should be placed at a minimum depth of two feet below
the lowest adJacent exterior final ground surface.
Reinforce and intercQnnect continuously with s.teel bars all interior and exterior
footirgs with two #4 bars at 3 inches above the bottom of all footill:)s and two
# 4 bars placed 1 1/2 I nches be low the top of the stems of the footi rgs •
Use rcdsed wood fl()ors that span between continuous footi'lls, or reinforce all
concrete slabs wi·th 6 x 6 -10/10 woven wire fabric, and provide a minimum of
4 Inches of clean sand beneath aU concrete slabs. Provide a moisture barrier
2 inches below slabs under IIvil'lJ areas .
BENTON ENGINEERING. INC.
•
•
•
•
•
•
•
•
•
•
Pr~iect No. 68-1'1'-230 •
La Costa South Uni·t No., 1
..,3-.' June 23, 1969
4. Separate garage slabs from perimeter footirGs by 1~ inch thickness of
construction felt or equivalent, to allow independent movement of garage
slabs relative to perimeter footill}s. '
5.. Pr.ovide positive drainage away from an perimeter footi~s to a horizontal
distance of ot .Ieast 6 feet ou tside the house wans. '
In addition to the filled ground placed and inspected within La Costa South Unit No. 1, there
was an drea ·of fill approximately 180 feet east of the east end of Navarra Drive. This drea is
shown on Drawing l\Io. 1; and the tests h;lken within the areq are Test Nos. 257, 258, 264 and
V~ .
Respectfully submitted,
BENTON ENGINEERING, INC.
By 2'J1f'"l' k...
M. V. Pothier~ Civil Ell}ineer
Distr : (4) Addressee
(2) Mcintire & Quiros, Inc.
Attention: Mr. Gary Cumbe.y
(1) Rick E~ineerirg
(2) San Diego County Buildill} Insp~ction.
Vista, California .-mailed 1-9-70,
BENTON ENGINEERINC;;, INC.
--.~ -.. --" _. -..
• Project No. 6S-11-230 I--4--June 23, 1969
La Costa South Unit No.
TABLE OF TEST RESULTS
• Approx-Depth Maximum
imate of Fill Field Dry Dry
Test Location at Test Moisture Density Density Percent
No. or lot No. tn Feet % dry wt Ib/cu ft Ib/cu ft COmpaction Remarks
1 La Costa Ave. 1 10.4 111.5 120.2 92.S • Sta.33+OO
2 La Costa Ave. 3 15.S 103.3 114.S 90.1
Sta. 34+63
3 La Costa Ave. 2 11.7 112.5 119.0 94.6
Sta. 35+25 • 4 La Costa Ave. 6 19.5 102.4 113.0 90.7
Sta. 35+50
5 La Costa Ave'. 7 19.5 103.7 114.7 90.5
Sta. 34+50
6 La Costa Ave. 5 16.5 101.5 110.6 91.S
• Sta. 33+50
7 La Costa Ave. 1 16.9 lOS.4 114.S 94.6
Sta.32+00
S La Costa Ave 0 10 17. 1 99.S 110.6 90.1
Sta. 35+63
• 9 La Costa Ave. 9 17. 1 105.9 114.0 92.S
Sta. 33+63'
10 La Costa Ave. 4 17.6 107.3 114.0 94.3
Sta. 36+00
11 3 2 19.2 103.3 114 .. S 90.0
12 55 2 14.7 112.5 122.3 92.0 • 13 La Costa Ave. 5 15.7 108.4 114.0 95.0
Sta. 32+50
14 La Gosta Ave. 11 16.2 109.5 114.0 96.2
Sta. 34+00
15 La Costa Ave. 2 16.7 10S.2 l.16.0 93.2 • Sta. 30+00
16 La Costa Ave. 4 17.S l06.S 114. 1 93.7
Sta. 30+00
17 3 4 20.2 103. 1 114.3 90.2
IS 4-1 16.2 100.6 116.5 86.4 Reworked
• 19 3 S 15.1 107.2 116.5 92.2 Check on If IS.
20 .4 5 15'.7 10S.3 120.2 90.1.
21 3 12 17.6 100.0: llO.6 90.5
22 La Costa Ave. 2 lS.6 100.S 110.6 91.2
Opp. 3 & 4
• 23 4 9 16.2 100.7 110.6 91.S
• BENTON. ENGINEERiNG. INC.
....... -~----. ~-.~ ~ -~~_." ....... "
• Profect No. 68-11-230 .,. -5-• June 23, 1969
La COsta South Unit No.1
TABLE OF TEST RESULTS (CONT.) .
• Approx-Oe~th Maximum
Q imate of Fill Field Dry Dry
Test Location at Test Moisture Densi-ty Density Percent
No. or Lot No. i-n Feet % dry wt Ib/cu ft Ib/cu ft Compaction Remarks
• 24 24 2 17.5 97.3 110.6 88.0 Reworked
25 24 2 14.8 107.8 118.0 91.4 Check on "24
26 23 4 14.7 109.2 118.0 92.6
27 24 6 14.7 108.2 118.0 91.7
28 23 8 16.7 99.5 110.6 90.0
29 24 10 22.5 100.0 110.6 90.3 • 30 25 1 10.8 105.8 116.0 91.2
31 23 12 14.4 103.9 114.8 90.5
32 22 1 16.0 100.6 110.6 91.0
33 21 1 16.5 103.0 110.6 93.2
34 24 14 16.0 103.9 113.3 91.6
• 35 22 5 16.8 107.0 118.0-90.6
36 La Costa Ave. 3 18.9 100.4 110.6 90.8
Opp. 24 & 25
37 20 1 14.9 104.6 114.8 91.2
38 5 2 16.0 110.4 ,119.0 92.8
• 39 6 2 15.7 108.0 119.0 90.8
40 La Costa Ave. 14 14.4 111.0 119.0 93.2
Std. 35+00
41 La Costa Ave. 13 14. 1 111.2 119.0 93.4
Sta. 33+00
• 42 2 16 13~5 105. 1 114.8 ' 91.5
43 4 13 15.6 110.6 119.0 93.0
44 La Costa Ave. 15 12.0 112.2 119.0 94.2
Sta. 34+00
45 La COsta Ave. 9 , 12.4 112.2 119.0 94.2
Sta. 32+00 • 46 5 6 11.9 110. 1 119.0 92.6
47 3 20 14.4 113.5 119.0 95.3
48 La Costa Ave. 6 15.5 108.6 119.0 91.3
Opp. 4 & 5
103.5 ,_ 49 La Costa Ave. 8 10.8 114.8 90.1
• Sta. 36+00
50 La Costa, Ave. 19 12.3 109.3 H9.0 91.9
Sta.34+OO
51 La Costa Ave. 13 12.5 109.3 119.0 91.8 Finished Grade
Sla. 32+00 • ~
• BENTON ENGINEERING. 'INC.
• Pr9ject No. 68-11-230 '. -6-• June 23, 1969
La Costa South Unit No. 1
TAB~E OF TEST RESULTS (CONT.)
• Approx-Depth Maximum
imate' of Fill Field Dry Dry
, Test Location at Test Moisture Density Density Percent
No. or Lot No. in Feet % drywt Ib/cu ft Ib/cu ft CompQction . Rem~rks
)
52 6 6 13.0 104.7 114.8 91.4
53 4 17 12.4 107.7 119.0 90'!5
54 La Costa Ave. 18 15.8 101.9 110.6 92. 1
Sta. 35+00
55 La Costa Ave. 17 10.7 108.3 119.0 91.0
Sta. 33+00 • 56 La' Costa Ave. 23 10.7 109.5 119.0 92.0
Sta.34+oo
57 3 24 19.5 ' 97.8 110.6 88.4 Reworked
58 5 10 12.0 107.6 119.0 90.4
59 La Costa Ave. 10 14.9 105.8 ' 114.8 92.0
• Opp ... 4 & 5
60 La Costa Ave. 12 . 17~6 106.8 114.8 93.0
Opp. 4 & 5
61 25 5 15.0 104.4 114.8 91.0
62 23' 16 13.5 107.6 119.0 90.4
• 63 83 1 14,.8 98.5 108.3 90.8
64 86 & 87 2 10.8 104.8 113.0 92.9
65 La Costa Ave. 12 ll.7 110.2 119.0 '92.6
Sta. 36+00
66 Lq CQSta Ave. 14 15.9 107.2 '119.0 90.2
• Opp. 3 & 4
67 La Costa Ave'. 16 13.7 109. 1 119.0 91 .. 7
Opp.36+00
68 24 18 12.7 107.6 119.0 90.4
69 La Costa Ave. 16 14.5 112.4 119.0 94.5
Opp. 4 & 5 • 70 22 9 13.7 109.0 119.0 91.6
71 'j 4 13.7 110.4 119.0 '92.8
72 La Costa Ave. 7 18.6 99.9 110.6 90.4
Opp. 24 & 25
73 La Costa Ave. 6 16.8 102 .8 110.6 92.9
• Opp. 24 & 25
74 7 8 13.7 103.8 110.6 93 .. 8
I 110.6 75 184 2 19.2 101.8 92.2
76 83 3 18.0 98. 1 108.3 90.6 "
77 83 ' 5 15.3 99.7 108~3 92.1,
• 78 83 7 12. 1 76.1 103.6 73.5 Reworked
79 86 & 87 4 -11 . 1 103.3 113.0 91.4
80 83 7 13.9 104.2 ' 113.0 92.3 Check on *78
• , BENTON ENGINEERING. INC.
" .. ~ ... -..-~~.-.... ~-.---.-~ ----
• Pr.oject No. 68-11-230 • -7-• June 23, 1969
La Costa South Unit No.1
TABLE OF TEST RESUJ,. TS (CQNT.)
• Approx-Depth Maximum
imate of Fill Field Dry Dry
Test Location at Test Moisture Density < Density Percent
No. Qr lot No. in Feet % dry wt Ib/cu ft Ib/cu ft Compaction Remarks
.:81 21 <' 5 14.9 99.5 110.6 90.0 • '82 . 17 1 13.8.,,, 107.1 119.0 90.1
83 19 1 13.5 104.3 114.8 91.0
84 '20 5 21.4 t02.8 113.0 91.0
85 23 20 14.9 106.3 114.3 93.2
86 La Costa Ave. 11 14.8 104.5 114.3 91.4
• Opp. 24& 25
87 < 184 <0 4 16.2 102.8 111.5 92.2
'88 64 2 15.4 105.9 115.5 91.9
89 176 2 13.3 104.6 115.5 90.6
90 La Costa Ave. 15 17.3 105.6 114.8 92.0
• Opp. 24 & 25
91 La Costa Ave. 19 16.8 106.8 114.8 93.2
Opp. 24 & 25
92 83 11 14.8 103.4 110.8 93:4-
93 La Costa Ave. 6 13.4 105.8 116.0 91.3
• Opp. 86 &:87
94 83 13 13.9 105.4 116.0 91.0
95 82 3 17.5 104.8 113.0 92.8
96 84 1 13.3 97.6 108.3 90. 1
97 83 17 16.0 105.8 115.5 91.6 '~i nlshed Grade
98 65 4 15.4 99.0 109.0 90.8 • 99 184 6 9.1 101.3 108.3 93.6
0100 67 & Viejo 4 14.8 99.6 109 .0 91.4
Cas ti \I a Way
101 176 6 16.9 100.9 109.8 92.0
102 69 2 12.3 98.2 108.3 90.7 • 103 184 8 18.2 105.7 114.8 92.1
104 64 6 ' 19. 1 101.9 113.0 90.1
105 182 2 14.3 96.6 103.6 93.3
, 106 68' 2 12.0 94.9 103.6 91.6
107 175 4 11. 1 102 .8 113.0 91.2
• 100 6"5 8 15.3 103.6 113.3 91.5
, 109 183 4 15.0 105.7 113.3 93.4
110 66 4 17' .. 4 103.3 113.3 91.3
111 La Coruna 4 14.3 105.7 110.6 95.4
Place
112 70 4 16. 1 105.7 .. 117.0 90.3 • 113 175 8 15.4 96.5 103.6 93.,0
114 71 & Viejo 4 19'.3 95.7 103.6 92.4
Ccstilla Way
115 173 4 15. 1 101.5 . 110.8 91.6
116 184 12 13.3 106.6 116.0 92.0
• 117 183 8 13.7 104.6 110.6 94.5
• BENTON ENGINEERING, INC.
--~_ 4 _
. . ..
• Pro·teet No. 68-11-230 • -9-• June 23, 1969
La COl·to South Unit No.1
TABLE OF lEST RESULTS (CONT .)
• Approx-Depth MQximum
imate of Fill Field Dry Dry
Test Location ' at Test Moisture bensity Density Percent
No. or Lot No. in Feet % dry wt Ib/eu ft lb/eu ft Compacti.n Rem.rks
151 5 18 24.9 98.4 109.2 90.1 • 152 7 20 11.5 107.3' 116.0 92.5
153 23 24 18.8 103.3 llO.6 93,4
154 24' 26 19.0 103. 1 110.6 9:3.2
155 22 ' 21 12.8 108.5 116.8 92.9
156 21 17 14. 1 109.5 120.6 90.7 • 157 20 13 12.8 10l.8 112. 1 90.8
158 19 5 14.4 109.9 117.2 93.8
159., ' 18 3 13.3 106.5 116.8 91.2
160 17 3 1~.5 106.3 116.8 90.9
161 17 5, 12.0 99.7 108.3 92.0
• 162 17 7 12 A 99.7 108.3 92.0
163 54 2 15 A 106.2 118.0 90.0
1Q4 55 4 9.9 116.2 124.0 93.7
165 54 6 6.6 110.8 120.2 92.0
166 55 8 7.7 120.7 128.0 94.2
• 167 54 10 8.9 113.7 125.0 90.9
168 55 12 8.9 119.5 128.0 93.3'
169 56 2 22.7 98.8 109.2 9004
170 54 14 15.0 108.0 118.8 90.9
171 Navarra Drive 4 10.4 117.3 128.0 91.6 ., Opp. 54 & 55
172 56 6 7.5 110.5 121.5 90.9
173 62 2 10.9 99.8 116.0 86.0 Reworked
174 Vie fo Costilla W.,2 12.6 104.8 116.0 90.2
Sta. 3+71
1-75 55 16 14.5 ' 111.7 121.5 91.9 • 176 Navarra Drive 8 5.0 116.0 125.0 92.8
Opp.55 Check on f/ 173 177 62 2 12.5 106.2 112.8 94.1
178 ViejoCastirlaW.2 11.5 ' 110. l' 116.0 94.9
Sta. 4+71
• 179 62 ·4 15.4 ta7.9 115.4 93.4
180 34 2 11.3 ,110 .5 115.4 95.7
181 57 2 5.0 112.4 12,5.0 90.0
182 54 18 12.7 108.4 118.8 91.3
183 Navarra ,Drive 12 10. 1 112.4 120.8 93. 1
• Opp. 54 & 55
• BENTON ENGINEERING, INC.
" ---~---.... ~ ~.-~ _ ..... -.. -. ----. -~----. -~~-----._---~-.--. -.--._.----~--~, -~r-----.-' .'
~J Pr~i.ct No. 6'8~ 11'-23D :. -10-• June 23, 1969 ;-La Cos,ta South Unit No. 1
TABLE OF TEST RESU L TS (CONT .)' r. Approx-Depth Maximum
imate of Fill Field Dry Dry
Test Location at Test Moisture-Density Density Percent
No. or Lot No. in Feet % dry wt Ib/cu ft Ib/cu ft Compaction Remarks
184 34 4 11.7 106.8 ' U3.4 94.2 :. 185 37 4 10.8 103.3 114.8 90.0
186 58 4 10.8 100.9 120.8 90.2
187 V,i e jo Cas fi II a W.6 12.8 107.0 112.7 94.9
Sta. 3+61
18i 57 6 15.7 106. 1 118.0 90.0 • 189 Viejo CastillaW.4 12.6 106 .9 112.7 94.9
Sta.4+71
190 La Costa Ave. 6 16.9 105.0 116.0 90.6
Sfa. 30+00
191 La Costa Ave. 8 '16.0 106.9 117.0 91.4
• Sta. 30+00
192 LoCos fa Ave. 2 12.0 1'12·.4 119.0 94.4
SfQ.31+00
193 La Costa Ave. 12 12.2-113.9 n9~O 95.6
Sta. 30+00
194 La Costa Ave. 22 11.0 111.3 119.0 93.4 • Sfa.35+00
-195 La Costa Ave. 20 10.9 113.0 119.0 94.9
Sta. 36+00
196 55 . 20 7.7 107.9 120.8 89.4 Reworked
19.7 . Navarra Drive' 16 9.5 105. 1 120.8 87.0 Reworked • Opp.54 & 55
,198 55 20 11.9 105.5 114.8 92.0 ChecK. on '196
199 Navarra Drive 16 12.7 105.6 114.8 92.0 Check on # 197
Opp. 54 & 55
200 39 4 9.2 105.3 ·114.8 91.6 • 201 37 4 12.2 l08.S . 118.8 91.6
202 '56 10 13.2 110.7 120.8 91.6
203 58 8 9.3 113.2 125.9 90.0
204 57 10 6.6 1.14.5 125.9 91.0
205 56 14 7.4 112.3 124.9 90.0
• 206 63 2 12.8 111.9 119.0 94.1
207 54 22 7.9 109. 1 121. 1 90-.1
208 63 3 . 13.S 110.1 119.0 92.4
2G9 57 14 10.6 l11.Q 120.8 92.2
2tO 112 2' 12.3 103.4 113.0 91.4
• 211 114 3 13.2 105.6 113.0 93.4
212 153 2 11.8 100.3 108.3 92.6
• BENTON ENGINEERING, INC.
• Project No. 68-11-230 • -11-• June 23, 1969
La Costa Sou,th Unit No. 1
TABLE OF TEST RESULTS (CONT.)
• Approx-Depth Maximum
imate of Fill Field Dry Dry
Test Location at Test Moisture Density, Density Percent
No. or ~ot No. Tn Feet % dry wt Ib/cu ft Ib/cu ft Compacti~n RemGrks
213 152 4 12.3 101.4 , 10~L3 93.5 e' 214 La Costa Ave. l' over 13.9 109.3 114.6 95.2
Sta. 30+90 5 torm drcii n
215 154 '2 10.6 ' 104.5 113.0 92.4
216 38 6 5.3 109.0 120.8 90.2
217 153 6 15.4 103.6 113.0 91.8 • 218 37 8 5. 1 129.7 131.0 99.0
219 69 6 10.0 104.5 113.0 92.4
220 '152 8 13. 1 110.3 121.0 91.1
221 154 6 12.6 108.7 120.6 90.2
222 153 10 14.6 102 .7 112.3 91.5
• 223 25 9 14.0 99.7 108.3 92.1
224 25 13 10.6 105.2 113.0 93.1
225 68 10 ' 14.3 104.0 112.8 92.3 Finished Grade
226 67 &, Nuevo 12 1~.8 103.9 111.0 93.6
Castilla Way
• 227 152 12 11.2 112.2 120.6 93.0
228 154 10 14. 1 107.7 117.7 91.5
229 166 2 10.9 97.7 108 .3 90.2
230 25 17 10.6 . 109.9 120.6 91.1
23·1 24 30 14.2 108.3 116.8 92.7
232 21 21 13.7 104.0 113.0 -92.0 • 233 183 12 13.2 100.3 108.3 92.6
234 55 24 7.2 109 .0 118 ;8 91.7
235 56 18 10.6 118.2 131.0 90.2
236 58 16 9.8 108.3 12Q.6 90.0
237 176 10 18.6 101.3 108.3 93.5
• ,238 176 14 14.(, 107.5 . 118.0 91.1
239 56 22' 11.2 ·..;114.8 125.9 91.1
240 57 18 ' 11.3 117.0 125.9 93.0
241 58 20 10.2 118.2 .131.0 90.2
242 57 22 10.9 119.2 131.0 91.0
• 243 56 26 8.3 113.5 125.9 90.1
244 55 28 10.8 1-13.5 125.9 90.1
245 ' 39 8 19.4 103.3 113.0 91.4
246 38 10 13.6 111.4 120.8 92.2.
247 36 4 13.4· 114.5 125.9 90.9
• 2.t8 54 26 11.3 123.4 131.0 94.1
249 58 24 8.7 125.3 131.8 95.0
250 54 30 9.5, 125.3 131.0 95'.6
251 57 26 8.9 124.8 131.·0 95. 1
• BENTON ENGINEERING. INC.
• PrGjecf No .• 68-11-230 • -12-• Ju ne 23, 1969
La COI'taSou th U ni t No.
TA~E OF TEST RESUL TS (CONT.)
,Approx-Depth MaXimum • imate ofFill Field Dry Dry
Test location' at t.st Moisture Density Density Percent
No. or lot No. in Feet % dry wt Ib/cu ft Ib/cu ft Compaction Remarks
252 Navarra Drive 20. 15.0 113.7 125.9 90.3 • Opp. 55 & 56
253 39 12 10.0 111.7 120.6 92.5
254 37 12 11.0 109.4 120.8 90.5
255 38 14 12.6 109.8 120.8 90.9
256 36, 8 14.,3 111.3 120.8 92.0
• 257 180' E. of E. ·2 9.9 128.9 131.0 98.3
end of Navarra Dr.
258 180' E. of E. 4 10.3 124.8 131.0 95.3
end of Navarra Dr.
259 35 , 2 13 .. 9 114.5 120.8 94.8
• 260 46 2 16. 1 112.3 '120.8 93.0
. 261 37 16 12.9 107.2 118.8 90.2
262 39 16 12.2 115.4 . 125.8 91.8
263 38 . 18 9.9 116.6 125.8 92.8
264 180' E. of E. 6 13.7 117.0 129.5 90.4
end of Navarra Dr. • 265 45 4 14.7 113.5 ·125.9 90.2
266 36 12 14.2 110.9 118.8 .93.3
267 Navarra Dr. 24 14.8 111.1 . 120.8 92.0
Opp. 54 & 55
268 37 20 14.4 112.3 120.8 93.1
,e 269 39 20 15. 1 109.9 120.8 91.0
270 180' E. of E. 8 15.5 111.0 , 123.5 90.0
end of Navarra Dr.
271 55 32 12.8 103.4 113.0 91.6
272 56 30 15.3 105.2. 116.0 90.7
• 273 58 28 14.0 112.5 123.5 91.1
274 La Costa Ave. l' over 13.8 109.5 113.0 97.0
Storm Drain pipe
Opp.23
275 La Costa Ave. )' over 14. ) 105.4 108.3 97.3 .
• Parkway, Qpp. pipe
Lot Line 23 & 24
276 lQ Costa Ave. I' over 14.9 112.9 120.6 93.7 Reworked
Opp. lot li ne pipe
24& 25
277 54 34 17.9 99.6 109.2 91.2 • 278 57 30 11.5 113.0 120.8 93.6
279 58 32 14.5 103.3 113.0 91.5
280 38 22 13.7 115.4 125.9 91.6
• BENTON ENGINEERING, INC.
• -Project No .68 ... 11 ... 230 • -"13-• June 23, 1969
-La Costa SouthlJnit No. 1
TABLE OF TEST RESULTS (CONT.)
• Approx ... Depth Maximum
Imate of Fill Field Dry Dry
lest Location at Test Moisture Density b.nlity Percent
No. or Lot No. in Feet % dry wt Ib/cu ft Ib/cu ft Compaction Remarks
281 39 24 12.2 109.3 120.8 90.5 • 282 37 24 14.7 102.3 113.0 90.5
283 36 16 16.4 101.2 109.2 92.7
284 35 6-15.7 103.5 113.0 91.7
285 131 2 17.0 104.2 114.9 90.7
286 La Costa Ave. 11 over 19.2 111.0 116.0 95.7 Check on #276
• Storm Drain pipe
Opp. Lot tine
24 & 25
287 LaC9sta Ave. 23 12.9 105.2 116.8 90.1
Opp. 23 & 24
• 288 166 4 11.0 98.1 lOS.3 90.6
289 La Costa Ave. 6 10.8 111.0 116-.0 95.6
Sta. 31+00
290 La Costa Ave. 16 15.3 110.8 120.2 92.1
Sta. 30+00
291 La Cos.ta Ave. 10 17.2 109.0 120.2 90.6 • Sta. 31+00
292 110 2 12.0 106.5 114.8 92.8
293 111 3 10.5 103.8 113.0 91.9
294 113 4 12.2 107.8 116.8 92.2
295 112 6 12.0 100.1 .108.3 92.3 • 296 166 6· 11.6 98.4 108.3 90.8
297 166 6 12.0 100.7 116.8 . 86.3 Reworked
298 110 & 1'11 7 12.6 102.3 113.0 90.S Finished Grade
299 166 6 '12.0 l08.S 120.6 90.0 Check on *297
300 166 8 12.4 104.8 t 12 .. 8 92.9 .' 301 166 10 12.2 114.6 120.6 9S.1
302 113 8 16.3-102.8 113.0 90.9
303 1 2 12.6 108.8 .116.0 93.8
304 l1S 1 13.8 104.3 115.4 90.4
305 116 3 13.4 100.7 108.3 92.1
• 306 1 4 12.7 113.7 116.0 98.0
307 118 2 12.3 109 . '1 116.8 93.4
308 119 4 12.7 106.7 116.8 91.3
309 1.18 6 11.S 103.3 113.0 91.3
310 117 1 12.7 105.0 114.5 91.7
311 116 & 117 5 11.7 102.4 113.0 90.6 _FI nished Grade • 312 119 8 12.9 103.8 114.S 90.6
•
--.----. ----.. -~ ----.----------.. ,. Projf!!ct No. 68-11-230 .• -14-• June 23, 1969
La Costa South Unit No. 1
TABL~ OF TEST RESULTS (CONT.)
• Approx-Depth MaXimum
imate of Fill Field Dry Dry
Test Location at Test Moisture Density Density Percent
No. or Lot No. in Feet % dry wt tb/cu ft Ib/cu ft Compactton Remarks
313 122 ·4 13.9 103.4 113.0 91.5 . • 314 123 9 13.7 104.5 113.0 92.4 Finished Grade
315 131 4 12.3 99.6 108.3 91.9
316 46 6 14.9 108 .. 9 120.8 90.1
3'17 45 8 14.2 105.4 115.8 91.0
318 44 1 17.0 111.2 120.8 92.1 • 319 44 '3 17. 1 110.8 120.8 91.6
320 46 10 12.5 108.8 116.0 93.7
321 45 12 11.2 111.3 116.2 95.9
322 43 3 14.2 108.3 119.8 90.4
323 43 5 7.7 101.6 118.8 85.6 Reworked
• 324 43 5 10.0 105.4 116 . .9 ,90.3 Check on '323
325 43 7 6.4 105.2 116.9 90.2 Reworked *
326 3 32 13.4 1'13.5 119.0 95.3
327 La Costa Ave. 18 14.9 113.0 119.0 94.9
Opp. 3 & 4
• 328 4 25 15. 1 107.5 114.3 94.1
329 5 22 17.3 104 .• 6 nO.6 ' 94.6
330 6 18 15.2 105.1 110.6 95.0
331 7 24 12. 1 110. 1 116.0 94.9
332 Navarra Dr. 2 14.3 110.2 120.8 91.2
• Opp. 45 8. 46
333 17 11 13. 1 102.3 113.0 90.6
334 Navarra Or. 4 11.8 97.6 118.8 82.2 Reworked
Opp.45 & 46. Fi nished Grade
335 4 29 16.4 107.8 118.0 91.3
336 25 21 12.3 107.4 116.0 92.6
• ' 337 24 34 14.4 109.7 114.8 . 95.5
338 25 25 14.0 115.3 120.6 95.5
339 23 28 20.5 104 .3' 114.8 91.0
340 24 38 13.5 112.3 120.6 93.1
341 23 32 13.7 113.6 120.6 94 .. 1 Fi ni$hed Grade
• 342 22 25 13.0 98.7 108.3 91.1
343 21 25 14. 1 106.0 116.0 . 91.3
344 25 29 12.5 119.2 124.~ 95.9
345 20 17 1'7.3 104.2 114.5 91.0
~ 19 9 16.,3 107.5 119.0 90.3
• 347 18 ., 15.9 '105.9 116.0 91.2
348 22 29 14.8 114.0 120.6 94.4
349 20 21 13.3 1'02.5 113.0 90.7
350' 19 13 14.4 111.0 119.0 93.2
* Finished Grade • BENTON ENGINEERING, INC.
-------
• Proiect No. 68-11-23D • -15-.' June 23, 1969
, La Costa South lJnlt No. 1
TABLE OF T~ST RESUL TS (~ONT.)
Approx.,. Depth Maximum • imate of Fill Field Dry Dry
Test Location at Test Moisture Densl ty Density Percent
No. or Lot No. in Feet % dry wt Ib/cu ft Ib/cu ft Compaction Remarks
351 18 11 15.1 107.7 116.0 92.7 • 352 21 29 13.5 109 .5 119.0 92.0 Fi nished 'Grade
353 169 2 11.9 113.0 120.6 93.6
354 170 4 13. 1 110.9 114.2 97. 1
355 171 4 14.0 112.5 116.8 96.3
356 168 6 12.5 111.3 , 116.8 95.5
• 357 169 6 18.0 99.6 109 .2 91.1
358 71 & Viejo '8 11.6 105.0 116.,0 90.5
Castilla Way
359 71 & Viejo 10 12.2 105.8 116.0 91.1
Casti 110 Way
• 360 71 & Viejo 12 13.2 104.7 116.0 90.2
Castilla Way
361 72 2 16. 1 109 .6 116.0 94.4
362 72 ' 4 15.9 109.3 116.0 94. 1
363 67 & Nuevo & 14 13.5, 105.3 ' 114.9 91.7 Finished Grade
• Castilla Way
364 66 8 11.6 109. 1 116.0 94.1
365 65 12 ' 12.0 106.8 116.0 92.1 '
366 66 12 15.4 106.8 116.8 91.4
367 171 8 14.6 102 .4 '113.0 90.6
368 167 2 11.8 107.5 116.8 92.0
• 369 172 6 12.0 108.S 116.8 93. 1
370 167 6 11.7 109.6 116.8 93.9
371 173 16 16.2 109.3 116.8 93.6
372 174 12 15.9 103.3 113.0 91.3
373 175 12 15.0 102.9 113.0 91 ;0 '. 374 174 16 13.8 104.8 116.0 90.3
375 175 16 16.5 100.7 11 1.1 90.6
376 174 20 15.0 104.6 116.0 90.1
377 177 2 14.6 115.7 120.8 95.7
378 183 12 13.5 108.1 110.6 97.7 I
379 177 6' 15.2 107.2 110.6 . 97.0 • 380 182 6 10.9 106:.3 113.3 93.7
381 183 16 14.9 .... 108.8 ' 116.0 93.7
382 '" La Coruna 8 19.6 104.2 115.6' 90. 1
, ' Place
383 182 10 16.0 104.3 113.3 92.1 • 384 La Coruna 12 17.0 108.3 115.6 93.7
Place
385 182 14 12.2 104.8 116.0 90.3
386 La Corurla 16 15.6 113 .. 0 120.6 93.6
Place • BENTON ENGINEERING, INC.
• Pro-ject No~ 6S-11-23D • -16'-• June 23, 1969
La Costa South Uni t No. 1
TABLE OF T~ST RESUL TS (CONT.)
Approx-Depth Maximum • imate of Fill Field .Dry Dry
Test Location at Test Moisture Deniity Density Percent
No. or ~ot No. in Feet % dry wt Ib/cu ft Ib/cu ft Compacti"n Remarks
387 64 10 8. 1 109.4 116.0 94.3 • 388 65 16 12.9 108.7 116.0 93.6
389 181 4 15.0 109.2 118.8 92.0
390 184 16 13.9 106.2 114.7 92.7
391 181 8 17. 1 108.4 119.0 91.1
392 20 25 14.7 110.2 119.0 92.6
• 393 J9 17 12.3 108.8 119.0 91.4
394 18 15 14.7 109 .7 118.8 92.2
395 17 15 20.0, 102.2 110.5 92.5-
396 -24 38 11.2 115.3 120.6 95.7
,397 _ La Costa Ave. 27 12.3 106.S 116.0 92. 1
• Opp. 24 ~ 25
398 39 28 12.5 110.9 119.0 93.2
399 Navarra Ori-ve 29 14.3 105.6 116.9 90.3 Finished Grade
Opp. 54 & 55
400 38 26 14.6 106.3 116.9 91..0
401 36 20 14.9 105.7 116.9 90.5 • 402 3 32 13.3 106.8 116.0 92.0
403 6 22 15.4 103.2 110.6 93.3
404 70 16 11. 1 106.0 116.0 91.3
405 172 10 12.1 107.2. 116.8 92.0
406 177 10 17.6 104.2 nO.6 94.2 • 407 Drain Rear 2 10. 1· lOS.6 116.0 93.5
lots 178 & 179 -
408-Drain Rear 4 10.7 111.3 119.0 93.6
Lots 1-78& 179
409 6 22 10. 1 114.0 119.0 95.7 .' 410' La Costa. Ave. 20
Sta. 30+00
12.9 107.8 114 .S 94.0
411 La Costa Ave. 14 14.3 104.8 110.6 94.8
Sta.31+00
412 La Costa Ave. 24 12.6 -111. 1 113.2 98. 1 Finished Grade .' Sm. 30+00
413 La Costa Ave. 18 10.7 112.6 119.0 94.6 Finished Grade
Sta. 31+00
414 La Costa Ave. 21 10. 1 116.4 125.0 93.1 Finished Grade
Sta. 33+00
415 La Costa Ave. 27 14.2 113.5 125.0 90.8 Fi-nished Grade • Sta. 34+00
• SENTON ENGINEERING. INC.
-~ --~ -. . --------· r /
..
~~, ,. .
• Project No. 68-11-230 • -17-• June 23, 1969
La ·Costa South Unit No.1'
TABLE OF TEST RESULTS (CONT.)
• Approx-Depth Maximum
imate of Fill Field Dry Dry
Test Loccitton at Test .Moisture Density Density Percent
No. or Lot No" in Feet % dry wt Ib/cuft Ib/cu ft Compaction Remarks
416 La Costa Ave. ,26 11.9 109.3 119.0 91.8 • Sta. 35+00
417 La Costa Ave. 24 12. 1 112.5 119.0 94.5
Sta .36+00
4·18 La Costa Ave. 28 11.8 113. 1 119.0 95.1 Fi nlshed Grade
Sta. 35+00 • 419 . La Costa Ave. 27 11.5 114. 1 11'9.0 95.9 Fi.nished Grade
Sta. 36+00
420 1 6.5 11.3 105. 1 116.0 90.8 Finished Grade
421 3 36 13.2 111.1 119.0 93.3 Finished Grade
422 4 33 12.5 106.8 ' 114.2 93.5 Finished Grade
• 423 5 26 13.4 113.2 119.0 95.1 Finished Grade
424 6 26 13.7 114.4 119.0 96.1 Finished Grade
425 7 28 ' 14.8 108.5 119.0 91.1 f=inished Grade
426 l.Q Costa Ave. 20 15. 1 111.S 113.3 98.5 Finished Grade
Opp. 3 & 4
• 427 17 18 14.9 101.4 110.6 91.6 Finished Grade
428 18 18 11.4 107.0 117.2 91.3 Fi nished Grade
429 19 21 12.0 109.8 119.0 92.3 Finished Grade
430 20 29 13.2 106.8 118.3 90.4 Finished Grade
431 * 11 Over ' 11. 1 111 .8 116.0 96.5
Pi'pe • 432. * 11 Over 12.0 119.0 12.1.4 98.0
Pipe
433 ** l' Over 13.4 120.4 125.0 96.3
Pipe Finished Grade 434 22 3} 12. 1 107.7 116.5 92.4
• 435 24 40 11.2 110.8 11~ .0 93.S Finished Grade
436 25 33 15. 1 112.7 119.0 94.7 Fi nished Grade
437 63 4 13 .. 3 106.7 116.0 92.0
438 63 6 13.7 104.0 115.2 90.2
439' 33 :2 12.6 105.1 116.0 90.6
• 440 62 6 14. 1 lO6.5 116.0 91.7
441 34 8 13.6 107.0 117.5 91.0
442 181 10 '13.2 99.5 108.3 91.7 Finished Grade
443 184 20 15.3 97.5 108.3 90.0. Finished Grade
* Intersections of La Costa Ave. and Nuevo CastU 10 Way over Storm Drain. • ** La Costa Ave. opposite Lot 64 over Storm Drain.
• 'SENTON ENGINEERING, INC.
.. .' ProJect No. 68-11-230 • -18-• June 23, 1969
.La CoSta South Uni,t No. 'I ~ ~
TABLE OF TEST RESULTS (CONT.)
Approx-Depth Maximum • imate of-Fi II Field Dry J Dry
Test Location at Test Moisture Oer.ity Oenaity Perce~t
No. or Lot No. in Feet % dry wt Ib/cu ft Ib/cuft Compaction Remarks
444 183 19 14.7 97.6 108.3 90.1 Finished Grade
• 445 182 17 13.6 107.2 115.9 92.8 Fi nished Grade
446 ~a Costa Ave. 30 12.6 113.5 119.0 95,4 Fi,nished Grade
Opp. 23 & 24
447 La Coruna 17 13.8 100.7 111.8 90. 1 Fi nished Grade
Place • 44a 56 34 14.6 105.6 116.9 90.3
449' 57 34 20.3 106.3 116.9 90.9
450 176 i8 13.6 106.1 116.0 91.4 Finished Grade
451 177 12 11.9 100.7 111.5 90.3 Fi nished Grade
452 175 20 15.5 ~ 102.8 113.0 90.9 Finished Grade
• 453 174 24 15.3 114.0 120.6 94.5 Fi nished Grade
454--173 20 15.8 103.2 108:3 95~3 Fi nished Grade
455 172 14 18.0 99.0 109 .0 90.6 Finished Grade
456 168 10 11.4 100.5 108.3 92.8 Finished Grade
457 170 8 15.3 98.4 108.3 90.7 'Finished Grade
458 58 36 11. 1 115.0 118.0 97.5 Finished Grade • .459 44 4 8.7 125.9 131.0 96. 1 Finished Grade
460 57 35 5.7 110.5 119.8 92.2 Finished Grade
461 56 37 5.7 100.8 111.1 90.7 Finished Grade
462 166 12 15.0 103.2 114.5 90.2 Finished Grade
463 152 14 9.8 100.0 108.3 92.4 Fi nished Grade
• 464 154 14 12.3 ' 112.8 120.6 93.S Finished Grqde
465 Lot Line 11 11.8 102.9 113.0 91.0 Finished Grade
118 & 119
466 114 5 11.4 100.6 108.3 92.9
467 115 7 10.9 105.5 116.0 9i.O Finished Grade
• ~8 Lot Line 10 14.6 91.8 108.3 90.2 Finished 'Grade ,
112 & 113
469 131 6 9.9 108.4 119.0 91.1 rinished Grade
470 91 & 92 2 16.4 98.6 116.8 84.4 Reworked
471 91 & 92 2 15. 1 100. 1 116.8 85.7 Reworked
472 91 & 92 4 17.0 106.2 116.8 91.0 • 473 89 & 90 10 11.6 101.5 108.3 93.7
474 89' & 90 12 10.7 103.9 1.14.5 90.6 Finished Grade
475 91 & 92 2 15.2 111.3 116.8 95.3 Check on'470
& 471
476 91 & 92 4 14.8 111 .5 120.6 92.5 Fi nlshed Grade
• -477 86 8. 87 8 13.0 107.7 119.0 90.5
478 101 & 102 2 12.6 105.8 115.5 91.6
• 8ENTON ENGINEERING, INC.
~ ---., .. ~ .' Profect No. 68-11-230 • .19-• June 23, 1969
La Costa South Unit No.1
TABLE OF TEST RE~ULTS (CONT.)
Approx-Depth Maximum • Imate of Fill Field Dry Dry
Test Location at Test Moisture Density Densi tY Percent
No. or lot No. in Feet % dry wt Ib/cu ft Ib/cu ft Compaction Remarks
479 86 & 87 10 13.9 104.7 116.0 90.3 • 480 101 &102 4 13.3 103.7 114.2 90.8 Finished Grade
481 86 & 87 12 14.2 113.2 120.6 93.9 ....... "
482 72 5 '15.9 101:6 108.3 93 .• 7 Finished Grade
483 71 & Vi,ejo 16 16.4-110. 1 119.0 93.5 Fi nfsh~d Grade
Cas tilla Way
• 484 86 & 87 14 14.4 112.0 120.6 92.9
485 70 18 15.5 107.0 119.,0 90.0 Finished Grade
486 69 8 10.8 101.4 108.3 93.6 Finished Grade
487 66 16 lOA 108.6 116;8, 93.0 Fi nished Grade
488 65 18 9. 1 106.7 115.5 92.3 Finished Grade
• 489 86 & 87 16 14.2 105.5 116.0 91.0 Finished Grade
490 64 14 12.3 109 .2 119.0 91.7 Finished Grade
491 63 12 14.6 110.4 119.0 92.7 Finished Grade
492 62 11 l2.2 103.5 114.8 90. 1 Finished Grade
493 33 5 8.0 108,.9 119.0 91.6 Fi nished Grade
494 34 12 8.5 109.5 119.0 92.1 Fi nlshed Grade • 495 VieJo Castil'la 10 9.9 117.3 119.0 98.7 Finished Grade
Way Sta. 3+71
496 VieJo Castilla 6 11.3 114.5 119.0' 96.2 Fi ni.hed Grade
Way Sta. 4+71
497 35 10 13. 1 107.8 119.0 90.5 Fi niShed Grade
• 498 36 23 12.3 115. 1 123.9 93.0 Finished Grade
499 37 2S. 16.2 105.3 116.9 90.1 Finished Grade
500 38 30 13.7 . 105.6 116.9 90.4 Fi nished Grade
. 501 39 30 8.6 117.8 125.0 94.2 Fi nished Grade
502 46 14 9.9 107.8 118.8 90.8 .' 503 45 16 12.2 117.8 125.0 94.2 Finished Grade
504 Navarra Dr. 4 7.4 107.5 118.8 90.6 Check on #334
.g Opp. 45'.& 46 Fi nished Grqd,
505 54 38 5.2 114.0 125.0 91.2 Finished Grade
so!' 55 36 5.0 115.6 128.0 90.4
•
••
• BENTON ENGINEERING. INC.
•
•
•
•
•
•
•
•
•
PrCl) ject No 0 -68-11-230 ."
La Costa South Unit No.1
..:20-
LAB ORA TORY TEST RESUl TS
• June 23, 1969
The maximum dry densities and optimum moisture contents of the major fill materials as deter-
mined by the A.S. i' .M. '0 1557-66T meth·~, that uses 25 blows of a 10 pound hammer falli~
from a height of 18 inches on each of 5 layen ina 4 inch di.ameter 1/30 cubic foot compaction
cyli nder, are presented as follows:
Maximum Optimum Mois-
Ory Density tu.re Content
. Soil TYPe -,Ib/cu ft % dry wt
ligh t yellow":broWn sil ty clay 114.8 14. 1
01 ive-green silty clay 110.6 15.7
Yellow..,brown silty fine sand 116.0 13.2
Yellow-brown silty fine sand 119.0 12.0
Gray-black silty clay 118.0 13.6
.light gray-brown fine sandy clay 120.2 12.2
Brown· clayey fine to medium sand 128.0 8A
Dark brown clayey fine to medium ,sand 131.8 7.4
Brown fine to.medium sandy clay 125.0 10.5
Brown sil ty clay 118.8 12. 1
light brown silty fine sand 103.6 15.5
Light brown sfl.ty fine sand 113.0 13.2
Brown silty fine sand with scattered gravel (topsoil) 120.6 10.5
light gray-brown streaks, yellow silty clay and 109.2 17.0
chunks ()f clayst~me
M~dium brown and streaks of rust and yell.ow fine: 113.0 13.2
sandy clay plus some chunks of cemented sandstone
Medium brown silty fi ne sand .121.4 11.7
Medium brown si I ty clay 120.8 10.6
Medium brown silty fine to medium sand plus 13).0 9.0
scattered coarse grains and gravel
Brown silty clay and clayey silt 116.9 14.9
BENTON ENGINEERINC;. INC.
•
•
•
•
•
•
•
•
•
•
•
•
BENTON ENGINEERING. INC.
APPLIED SOIL MECHANICS -FOUNDATIONS
6741 EI,. CAJON BOULEVARD
.AN DI~GO. CALIFORNIA 921115
PHILIP HENi<ING BENTON
PRESIDENT,. CIVIL ENGINEER November 30, 1970
RQncho La Costa, Inc.
Route I, Box 2550
Encinitos, CaliJornia 92024
Subject:
Gentlemen:
Project No. 68-11 .. 23p, Supplement
~eport on Compacted Fi lied Ground
La Costa South Unit No. 1
Rancho La Costa, California
•
SAN DIEGO: 1583·156154
LA MESA. 469·156154
On June 2$, 1969, we ,submitted what we then believed to be a final report on compacted
frlled ground for fhe above unit. However, additional filled ground was placed and compacted
on the unlt subsequent to the report; thi~ is to report the results of the tesrs and observations
made in order to inspect the compaction of that additional fi lied ground, whkh was placed,
during the period between October 30, 1969 and June 24, 1970. The lots on which the addi-
tional fi-1:I~d ground reported herein was placed include Lots 62, 63, 91, 92, 93, 110 to 114i
inclusive, 122, 123 and 148 to 151, inclusive.
The final approximate areas and depfhs of filled ground placed on this unit under our inspection
in accordance with the approved specifications are shown on the attached Drawing No.1 which
has b,een revised to include the additional filled ground covered by this sIJpplemental report.
The approximate locations of the tests taken subsequent to June 23, 1969C!re presented on pag~
No. nunder the"Table of Test Results:' and the laboratory determinedationsof the maximum
dry dentities and optimum moisture, contents of the major fill materials placed as additional fill
are presented on page No. T2 under the "Laboratory Test Results.1I Some of the maximum dry
densities shQwn in the "Table of Test Results" on page No. T1 were combinations of these. The
tests reported herein were taken during the weekly periods indicated below:
Test Number Week Ending
507 'fo 509, inclusive
510 to 519, inclusive
520 to 529, inclusive
030, to 538, inclusive
539
540 and 541
542
November 1, 1969
December 6 i 1969
January 17, 1970
January 24, 1970
February 28, 1970
March 21, 1970
June 27, 1970
• Project No •. 68-11-23D, Su~ent
Rancho La Costa, Inc. 'w -2-• November 30, 1970
The final results of tests and observations indicate that the compad~d filled ground has been·
placed at 90 percent of the maxiQ1u!1l dry density or greater • It has been determined that the
fill materials, compacted to 90 per~ent of the maximum dry density, have a safe bearing value
• of at. least 1510 'pounds per square foot for one foot wide continuous footings founded at a mini-
mum depth and placed five feet or more inside the top of compacted filled ground slopes. If
footings qrf3 placed closer to the exposed slopes than 5 feet inside the top of compacted filled
ground slopes, these should be deepened one foot below a 1 1/2 horizontal to 1 vertical line
projected 'ou.tward and downward from a point 5 feet horizontally insicle the top of compacted
• fi lied ground slopes. Tests indi cate that the compacted fi l.Ied ground is adequate to satisfactory
support the proposed one and two story wood frame dwell.ings without detrimental settlements.
~xpansive clay soils were placed within the upper 3 feet on Lots 62 and 63, therefore the
following special design precautions are recommended:.
••
•
•
•
•
•
•
•
L
2.
3.
4.
5.
. 6.
"
Avoid the use of isolated interior piers. Use continuous footings
throughout; and place these at a minimum depth of two feet below
the lowest adjacent exterior final ground surface.
Reinforce and interconnect continuously with steel bars aU interior
and exterior footings with one #5 bar at 3 inches above the bottom
of the footings and one #5 bar placed 1 1/2 inches below the top of
the stems of the footings.
Exercise every effort to assure that the soil under the foundations and
slgbs has a uniform moisture content, 1 percent to 3 percent greater than
optimum throughout the top 3 feet below finished grade at the time of
placing foundations and slabs. .
Use raised wooden floors that span between conHnuous footings, or use
all concrete. slabs with 6 x 6 -10/10 welded wire fabric .and -provide a
minimum of 4 inches of clean sand beneath all concrete slabs. Provide
a moisture barrie~ 2 inches below slabs under living. areas.
Separate garage' slabs from pe'rimeter foot.jngs by a· .1/2 inch thickness of
construction felt or equivalent, to allow independent movement of garage
slabs relative. to perimeter footings.
Provide positive drainage away from all perimeter footings to a horizontal
distance of at least 6 feet outside the house walls.
This supplemental report p'lus Jhe report of June 23, ]969, comprise our final report of compa,cted
filled ground placed on this unit, as of this date. This supplemental report reflected only the,;
changes that have occurred inside Lots 1 to 184, inclusive, in Ld Costa' South Unit No.1 since
.our report of June 23, 1969, same subjeet.as above.
Respectfully submitted, Distr:
BENTON ENGINEERING; INC.
BYYtv~
M. V • Pothier, Civi'l Engineer
BENTON ENGINEERING. INC.
(4) Addressee
(2) Mclntire & Quiros, Inc.
Attention: Mr. Gary Cumbey
(1) Ri'ck Engineering
(2) San D.iego County Building Inspection
Vista, California '
Protect No. 68-11-230' • T1 • November 30, 1970 • La Costa South Unit No. 1
tA$.,~Ri.QF TE~T RESULTS,
Approx-Dep.th, ' Maximum
• imate ~f.Fi4I 'Fiedd Dry Dry
Test Location qt rest, ' MQisture Density Density Percent
,Nc:)'~ or'l.ot No. in Feet " .:i~{i dry w.t Ib/cu ft' "Ib/cu ft Compaction Remarks
507 123 2 17'~6 102.5 111.8 91.7
• 508· 123 6 15:.4 105.5 111.8 94.5 ;; Finished Grade 509 123 9' ~4 9 ' 106-.5 111.8 95.3 . .
510 150 2 'S.t 107.0 118:2 90.5
5J1 148 ' 2 11~,9 104.8 '113.9 92.0
51;2-149 4, :11.9 " 106~8 116.0 92.1
• '~l3 ,151 "4 ,:lO~6' 106'.0 ,116. 1 91.3
$'1~ 1~ 6 lL2 106.5 -11'6.1 91.7
5:15 151 8 ~ 1 •. 8 101. 1 111.8 90.5
51'6 150 10 14.2 109.3 ' , 113.9 96.1
S:17 149 8 '10.4 107.3· 113.9 94.3
5;18, 151 " ' 12 . 12~7 106.2 113.9 93.3 • 5':1'9" 150 14 n.-6 106.8 113'.9 93.7
.,20, 148· 5 12~_9 105.0 113.9 92.2 Finished Grade
52:1' 149 12 12 ~ 1 105.2 113.9 92.4 Finished Grade
522 151 15 12.3 106.2 113.9 93.3 Finished Grade
523 150 19 12'-.. 2 105.6 113.9 92.8 Finished Grade
• 524 -62 13 " ,11.,2 115.3 118.0 97.9
525 62 15 , 11.:2, 120.2 122.1 98.5
526 62 17 11.2 106.0 115.1 92.1
5'i7 . 62 19 10.0 109'.3 114.2 95.~ .
528, 63 16 ' 11.;4 112.0 115. 1 97.2-
• 529' 63 20 13.9 112.3 117.9 95.-4
530 ·91 2 ',15.2 104.9 115.0 91.2
531· 92 4 15~5 104.2 114.0 91.5
532 91 6 14.9 105.8' 114.0 92.8 Finished Grade
sa:f 93 2 14 •. 8 104.9 114.0 92.0 Finished Grade
• sa+' 62 21 15A 109.2 . ' 117.8 92.8
535' 6Z 23 17~8 109.1 117.8 92 •. 7
536 62 25 '17d 105.9 114.0 92.9
537 " 62 27 19 •. 1 10~·.9 117.8 92.5
.538 62 29 15A 111.6 114.0 97.9 Finished Grqde
539 . 63 24 16.4 10748 . 114.0 94.6." Fin ished Grade • 540 113 2 10.6 113.4 118.2 96.0
54·1 113 4 '14.2 103.5 . -113.5 91.3 Finished Grade
542 111 2 10.5 106.1 113.9 93 •. 2 Finished Grqde
•
• BENTON ENGINEERING, INC.
• Protect No. 68-11-230 .•
La Costa South Unit No. 1
T2
LABORATORY TEST RESULTS
• November 30, 1970
The maximum dry densities and optimum moisture contents of the malor fill materials as deter-
• mined by the A.S.T .M. 0 1557-66J method, that uses 25 blows of a 10 pound hammer falling
from a height of 18 inches on each of 5 layers in a 4 inch diameter 1/30 cubic foot compaction
cy Ii nder, are presented as fo! lows:
•
•
•
•
•
•
•
•
•
Soil Type
light brown silty very fine to fine sand
with clay binder
Brown silty fine sand,(Topioil)
Gray-brown slightly. silty flne sand
Gray fine sandy clqy .
Light greenish-gray slightly clayey
fine sand
Light gray very fine .to fine sand
Olive-green silty clay
Yellow-brown silty fine sand with some
. clay binder
Brown silty fine sand (Topsoil)
Gray-brown fine to medium sandy clay
Gray-brown fine sandy clay
Ye:llow-brown silty very fine to fine $Cnd
Red-brown silty fine to medium sand (Topsoil)
Olive-green clay
Olive-green silty clay
Maximum
Dry Density
Ib/cu ft
111.8
118.2
113.9
117.4
122.1
114.0
110.6
113.0
117.9
117.8
114.2
112.3
117. 1
109.0
·110.5
BENTON ENGINEERING. INC.
Opt imum Mois-
ture Content
% dry wt
12.6
12.9
13.3
13. 1
11.5
14.2
15.7
13.5
11.5
12.2
13.0
13.8
12.6
16.6
16.3
r--,_ -
•
PHILIP·H.ENKING SENTON
PRESIDENT· CIVIL ENGINEER
Rancho La Costa, Inc.
• •
BENTON ENGINEERING. iNC.
APPLlltD SOIL MECHANICS ~ FOUNDATIONS
6741 EL CAJON SOULEVARD
SAN DIEGO, CALIFORNIA 92115
April 11, J969 SAN DIEGO: 583·S654
!-A MESA: 469·5654
• Rou te .1, Box 2550
•
,.
•
•
•
•
Encinitas, Cali'fornia 92024
Subj~c:t:
Gentlemen:
Project No. 68-11-230
Results of Field Density Tests
Taken in Backfi II Soils
La Cpsta Avenue
La Costa South UnU No.
San Diego County, California
This is to report the resuLts of eight field density tests taken in soils placed as backfill over
storm drains in La Costa Avenue durirg the period between March 17 and April 1, 1969.
The approximate 10catiQns at whi'ch the tests'were taken and .the final test results are pre-
sented .in the followi~ tabulation:
Test
~.
140
141
142
214
274
275
276
,28-6.
Maximum *
Approx-Field Dry Dry
imate Depth Moisture Density Density Percent
LOcatio.n .of Test % dry wt Ib/cu ft Ib/eu ft Compac.ti on Remarks
Opposite 1 foot above 17.4 105 .0 114.3 92.0 Reworked
3/4 Lot Line top of pipe
Opposite 1 foot above 14.2 111.4 1l4.8 97.1 Chackon #140 '
3/4 LQtLine top of pipe
Sta. 31+40 1 foot above 15.5 108. 1 112.9 96.0
top of pipe
Sta. 30+90 1 foot above 13'.9 109.3 114.8 95.2
top of pipe
Opposite 1 foot above 13.8 109.5 113.0 97.0
Lot 23 top of p,ipe
Parki~ Area 1 foot above 14. 1 105.4 108.3 97.3
OpPQsite top ,of pipe
23/24 Lot Line
Opposite 1 foot above 14.9 112.9 120.6 93.7 Reworked
24/25 Lot Li ne top of pi pe
Opposite 1 foot above 19.2 111.0 116.0 95.7 Check on '1276 ,
24/25 Lot Line top of pipe
* Some of the maximum dry densities shown are combinations of two or more' types of soil
• Projec:t No. 68-1 h·23D '.
La Costa Avenue
La Costa South Unit No. 1
-2-• April 11, 19,69
LAB ORA TORY TEST RESULTS
,. The maximum dry densities and optimum moisture contents of the major fill materials as
determined 'by the A.S.T .M. 0 1557-66T method, that uses 25 blows of a 10 pound hammer
fQlIl~ from a height of 18 inches on each of-5 layers in a 4 inch diameter 1/30 cubic foot
compaction cyli nd~r, are presented as follows:
•
.'
•
•• , .
•
•
•
•
•
Soil Type
Dark gray sil ty clay
Greenish gray silty clay
Yellow-brown 5i I ty fj ne sand
Yellow-brown silty clay
Ugh t broWn si I ty fi ne sand
Light brown silty fine sand
Brown sil ty fi ne sand
R~spectfuHy submitted,
BENTON EN<;7INEERING, ,INC •
Distr: (1) Addressee
(1) San otego County'
,E~ineeri~ DepOrtment
Mr .. Jack KeHhofer
BENTON ENGINEERING. INC.
,Maximum
Dry Density
Ib/cu ft
118.0
110.6
116.0
114.8
113.0
103.6
120.6
Optimum Mols-
o ture Content
.% dry wt,
13.6
15.7
13.2
14. 1
13.2
15.5
10.5