Forest Cove 1-CS 980921 SHIMEK, JACOBS & FINKLEA, L.L.P. tx_jg q b O
CONSULTING ENGINEERS
8333 Douglas Avenue. ~820 Dallas, Texas 75225-5816 Fax (2141 361-0204 Phone (214) 361-7900
ROSS L JACOBS. P.E
RONALD V CONWAY. P E.
JOHN W. BIRKHOFF. P E
JOE R. CARTER. P.E September 21. 1998
GARY C HENDRICKS. P E.
I C FINKLEA. P E.
Mr. Kenneth M. Griffin, P.E.
CiD' Engineer/Assistant City Manager
City of Coppell
Post Office Box 478
Coppell. Texas 75019
Re: Sandy Lake Road Water Line
Backfill Compaction Testing
Dear Mr. Griffin:
We are enclosing the backfill density test report prepared by Henley, Johnston and Associates. lnc for the
Sandy Lake Road water line project. From our review of the results it appears that the backfill densities
generally meet the requirements for backfill compaction of the North Central Council of Governments
specifications (NCTCOG Item 6.2.9b(2)).
Three locations are indicated to have densities less than 90%. However, all three are within the upper two
feet of the backfill. It is our opinion these isolated cases will not adversely affect the construction or
performance of the proposed brick screening wall adjacent to the water line project.
We are available to discuss this project further at your convenience.
Sincerely~s.~
. ic:d /
cc: Mr. Lan')..' Davis
J CLERICALK'OPPELL O~I4q*I. ETTERS CONSr.ca:,2 loc
HENLEY
JOHNSTON
& ASSOCIATES, INC.
16 September 1998
Land~ark
166~ ~armon Road
Fo~ ~oKh, Texas 76177
AEention: Mr. Joe Swinnea
Re: Densi~ Tests
Water Line Bacilli
Sandy Lake Road
Coppell, Texas
HJA 6949
Dear Mr. Swinnea:
In acccrdance with our recent discussions, we have completed post-construction density
testing of backfill along the Sandy Lake Road water line, from approximately Station
77+87 to Station 9§+46, in Coppell, Texas. A truck-mounted geotechnical drilling rig
was used to push Shelby Tube samplers into the soil to about 3-foot depth over the
water line and about 6-foot depth in bore pits. Samples were taken at about 1-foot
interval's. At two locations, Station 77+87 and Station 92+90, bulk samples were
obtained by augering to about 3-foot depth.
All She!by Tube samples obtained from the borings were extruded from the sampler in
the fiel~ and encased in polyethylene plastic to prevent changes in moisture content and
to pres?ye in situ physical properties. The samples were labeled as to appropriate
boring [~umber and depth, and placed in core boxes for transport to the laboratory.
I samples were classified in the laboratory in accordance wfth the Unified Soil
Classifi~:ation System. Moisture Content and Unit Dry Weight were determined for each
Shelby ~ube sample. The sample at 0 to 1-foot depth in Boring No. 3 (Station 85+86)
was so!, dry that it crumbled when unwrapped in the laboratory and only a moisture
content' test could be performed for this sample. The above test data are summarized
on Plates I and 2. Standard Proctor Compaction tests (ASTM D 698) were performed
on eac~ bulk sample. The results of these tests are presented on Plate 2. Each Shelby
Tube s~mple was matched to one of the compaction tests and dry density of the sample
compa~d to the maximum dry density determined by the appropriate compaction test.
These C, omparisons are tabulated for each sample as percent o1: maximum dry density
on Plates 1 and 2.
t~,~,'phone !(214! 941-3,508 J'o,.z (214) 943.7645 2.35 Mor.q~rt Aue.. DoJ!,',.~. Texas 75203.1088
i
This mlethod of tes'i + '
[ng can vary ,rom results provided by on-site field density check tests
during construction, but does provide a basis for determining if the material was placed
consis.tently and generally in accordance with specifica'.ions. The sample taken and
tested [by this method is smaller than the volume of material typically included in the
moistu're and density measurements by nuclear methods. Small inclusions in the
physic~l sample could cause variations that might be "averaged" in the larger sampling
volum& of the nuclear gauge. For example, inclusion of a piece of gravel or rock
fragment in the sample may provide a "high" density and a "low" moisture content; A
void, dr inclusion of organic matter, may provide a "low" density and "high" moisture
content. Pushing a sample tube into the soil and extracting the sample from the tube
will disturb the soil, even though the sample is considered "undisturbed" for geotechnica[
testing! purposes.
Some ~,ariations in density are noted in the samples obtained for this investigation. We
understand that the samples obtained in Boring No. 8 were in soil that had not been
excavated for the water line installation. It should be noted that the upper two feet of
materi~l at this location had high densities compared to the maximum dry density; below
two fee.'t, the density drops off considerably. We wculd expect that in the natural state
the upp.. er materials may have relatively high densities partially because of the relatively
dry conditions at the time of the sampling and partially because construction equipment
may have run over this location many times during construction of the water line. We
wo,_zld ~r~fic. ipe~ that, in normal moisture conditions, natural soils near the sudace wil""'-~
ty~pically have densities near 85 to 90 percent of the rn_aximu.rn dry density determined
by a Standard Proctor Compaction test.
The Optimum Moisture Content for both Proctor samples is about 13.5 percent. In
Bering Nos. 1 and 2 below about 3 to 4-foot depth, the moisture contents are very Iow,
ranginc~ from about 3.5 to 7 percentage points below Optimum Moisture Content. The
upper 2 to 3 feet of soil in Boring Nos. 3 and 4 also is very dry with moisture contents
about 4 to 7.5 percentage points below Optimum and the upper 1 foot of Boring No. 9
is very Iow in moisture content. Two high moisture content areas were noted - about 1
to 3 fe~t in Boring No. 2 and about I to 3 feet in Boring No. 5.
We do ~ot know what the specifications require for this project; the above comments
are get'oral observations from the data obtained from this investigation.
HENLEY
JOHNSTON
& ASSOCIATES, INC.
Landngark Page 3
Mr. Jo~ Swinnea
16 SeCtember 1998
i
We tru=st~ that this provides the information you need at this time. Please call us'if you
ha, ve a.ny questions or when we can be of further assistance to you.
Sincerely,
John W. Johnston, P.E.
Executive Vice President
Henley-Johnston & Associates, !nc.
JWJ
Encls.
HENLEY
JOHNSTON
& ASSOCIATES, INC.
WATER LINE IN SANDY LAKE ROAD
COPPELL, TEXAS
SUMMARY OF LABORATORY TESTS
BORI~qG STATION DEPTH MC DUW PROCTOR % MAXIMUM
NUMB, ER NUMBER (ft) (%) (pcr) DRY DENSITY
B-1 4.0-5.0 6.5 101.5 002 89.0
8-1 5.0-6.0 7.3 119.8 002 100 +
/~ B-2! 83+35 0.0.1 .O 16.9 106.7 002 93.6
002
95.7
I
B-al 85+86 0.0-1.0 6.2 *
B-3 2.0-3.0 14.7 109.6 002 96.1
/~B-4 87+89 0.0-1.0 6.5 115.4 002 100+
B-4 ~ 1.0-2.0 9.3 101.1 002
,~,J~,O' ~ B"4i 3.0-4.0 11.8 107.7 002 94.5
B-4! 4.0-5.0 10.9 103.g 001 90.3
13-4 ' 5.0-6.0 11.4 113.8 001 99.0
HENLEY
JOHNSTON
& ASSOCIATES, INC.
P~TE 1
S00'd 8888-6~-L[8:13~ NaV~NYq 00:~l
WATER LINE IN SANDY LAKE ROAD
COPPELL, TEXAS
SUMMARY OF LABORATORY TESTS
BORING STATION DEPTH MC DUW PROCTOR % MAXIMUM
NUME~ER NUMBER (fl) (%) (PC0 DRY DENSITY
B-6 94+68 0.0-1.0 13.5 119.6 002 100+
B-6 2.0-3.0 15.8 107.6 002 94.4
8-6 5.0-6.0 16.0 110.0 002 96.5
I B.7! 95+46 0.0-1.0 12.3 115.6 002 100+
~/~1~{~-('~ 8-8 92+90 0.0-1.0 11.9 120.6 092 100+
~' ,~ B-8 1.O-2.0 15.8 114.3 002 100+
~ B-8 2.0-3.0 17.6 106.1 002 93.3
a-~ ~+a7 0.o-~.0 a.s ~2o.~ oo~ ~oo+
~' B-9 1.0-2.0 13.6 ,12.1 00' 97.5
q~ B-9 2.0-3.0 3].1 102.9 001 89.5
SUMMARY OF STANDARD PROCTOR DENSITY TESTS
C01 Brown and reddish brown sandy clay witl~ some gravel
Optimum Moisture Content: 13.7 %
Maximum Dry Density: 115.0 pcf
C02 Brown clay w{th some weathered limestone fragments
Optimum Moisture Content: 13.5 %
Maximum Dry Density: 114.0 pcf
* Unable to trim sample.
HENLEY
JOHNSTON
& ASSOCIATES, INC.
P~TE 2
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