CF-Fire Station 1-LR081125
G
E Consulting Services, Inc.
2530 Electronic Lane
Suite 710
Dallas, Texas 75220
Geotechnical, Materials and Environmental Engineering
214.351.5633
FAX 214.351.5680
www.gmeconsult.com
November 25,2008
City of Coppell
Attn: Mr. Rock O'Dell
255 Parkway Boulevard
P. O. Box 9478
Coppell, TX 75019-9478
Subject:
Summary of Free Swell Testing
FIRE STATION NO.1 STORAGE BUILDING
Coppell, Texas
GME Project No. 08.05.0268.0014B
Dear Mr. O'Dell:
GME Consulting Services, Inc. (GME) appreciates the opportunity to submit this letter
summarizing the results of free swell testing performed on electrochemically-injected soil
samples obtained at the above referenced project site.
First Phase of In iection- Entire Pad
The first phase of electrochemical injection of the building pad began on November 3,
2008 and was completed on November 4, 2008. After a post-injection waiting period of
over 72 hours within each section, test borings were performed to confirm that the swell
potential of the materials had been reduced to the specified levels.
An all terrain vehicle (A TV) drill rig was used to drill the test borings and obtain soil
samples at each boring location. The test borings were drilled and continuously sampled
to depths of 10 feet. The samples were placed in plastic bags, sealed and returned to the
GME laboratory for free swell testing.
The following tables summarizes the locations of the two test borings and the results of
the free swell tests performed on the soil samples obtained at the project site on
November 11, 2008.
Free Swell Testing- Fire Station No.1 Storage Building, Coppell, Texas
GME Project No. 08.05.0268-0014B
Page 2
Summary of Test Boring Locations - First Injection Phase
Test Boring Boring
No. Depth, ft Boring Location
CB-l 7 NW Quadrant of Building
CB-2 7 SE Quadrant of Building
Summan of Free Swell Test Results
Overburden Free
Boring No. Sample No. Depth, ft Pressure, psf Swell, %
CB-l 1 0-2 125 0.40
CB-l 2 2-4 375 0.00
CB-l 3 4-6 625 0.80
CB-l 4 6-8 875 1.73**
CB-l 5 8-10 1125 2.67**
CB-2 1 0-2 125 0.00
CB-2 2 2-4 375 0.80
CB-2 3 4-6 625 0.80
CB-2 4 6-8 875 0.00
CB-2 5 8-10 1125 0.00
Free Swell Average 0.72
** Test result exceeds maximum allowable value.
The acceptance criteria for the electrochemically-injected soils were provided within
Appendix 0 of GME Report No. 08.04.0062 dated April 2, 2008. The criteria requires
that the average of laboratory free swell tests is 0.8 percent or less within the 10-foot deep
injected areas of the building pad and that no individual swell test exceeds 1.6 percent. For
the 2 test borings in the building pad area summarized above, the average free swell
measured was 0.72 percent with the measured swell for two individual tests within CVB-
1 above 1.6 percent.
The daily logs provided by the injection sub-contractor (ESSL) indicated that 66,900
gallons of water containing 230 gallons of electrochemical (a dilution ratio of 291:1
water to chemical) was injected into the building pad. This ratio meets the required
dilution ratio of 300: 1 water to chemical.
Based on the results of this phase of testing, it was GME's opinion that the south half of
the building pad represented by test boring CB-2 had been satisfactorily injected with
electrochemical solution. However, the north half of the building pad area represented by
CB- I had not been satisfactorily injected and would require additional injection. Based
on the test data, the re-injection depth for the north half of the building pad would be the
full 1 0 feet.
Second Iniection Phase - Re-iniection of North Half of Buildine Pad
The re-injection of the north half of the building pad (represented by CB-l A) began on
November 14, 2008 and was completed the same day. The depth of re-injection was 10
feet. After a post-injection waiting period of over 72 hours, a test boring was performed
in the injected building pad to obtain representative soils samples for testing. This testing
Free Swell Testing- Fire Station No. I Storage Building, Coppell, Texas Page 3
GME Project No. 08.05.0268-0014B
was to determine whether the swell potential of the materials had been reduced to the
specified levels.
One new test borings (CB-l A) was drilled near the location of original confirmation test
boring (CB-l). An all terrain vehicle (A TV) drill rig was used to drill the test boring and
obtain soil samples. The boring was drilled and sampled to a depth of 10 feet. The
samples were placed in plastic bags, sealed and returned to the GME laboratory for free
swell testing.
The following tables summarize the location and depth of the one test boring and the
results of the free swell tests performed on the soil samples obtained at the project site on
November 17,2008.
Summary of Test Boring Locations - Second In.iection Phase
Test Boring Boring Depth, ft Boring Location
No.
CB-l A 10 NW Quadrant of Building
Summary of Free Swell Test Results (Second In.iection Phase)
Overburden Free
Boring No. Sample No. Depth, ft Pressure, psf Swell, %
CB-l A 1 0-2 125 0.53
CB-l A 2 2-4 375 0.00
CB-l A 3 4-6 625 0.93
CB-l A 4 6-8 875 1.33
CB-IA 5 8-10 1125 0.00
Free Swell Average 0.56
Within the building pad area, the acceptance criteria required that an average of
laboratory free swell tests of 0.8 percent or less within the 10-foot deep injected areas of
the building pad with no swell test exceeding 1.6 percent be obtained. Recalculating the
average swell for the 2 test borings in the building pad area using the new data from CB-
I A summarized above, a revised free swell average of 0.44 percent with no individual
free swell test above 1.6 percent was determined.
The daily log provided by the injection sub-contractor (ESSL) indicated that 15,000
gallons of water containing 53 gallons of electrochemical (a dilution ratio of 283: 1 water
to chemical) was injected into the building pad during this second phase of injection. This
ratio is within the specified dilution ratio of 300: 1 water to chemical. Based upon the
logs, the total concentration of the total fluids injected indicates a total of 81,900 gallons
of water containing 283 gallons of electrochemical (a dilution ratio of 289: I water to
chemical) was injected into the building pad. This ratio meets the specified dilution ratio
of 300: 1 water to chemical.
Based on the results of the injection testing, it was GME's opinion that the building pad
had been satisfactorily injected with electrochemical solution. GME provided verbal
notice of these results to the contractor on November 19, 2008. We further indicated to
the contractor that placement of the special fill layer in the building pad could proceed.
Free Swell Testing- Fire Station No.1 Storage Building, Coppell, Texas Page 4
GME Project No. 08.05.0268-0014B
We appreciate the opportunity to provide these services to the City of Coppell. Should
you have any questions about information in this letter, please do not hesitate to call the
undersigned at (214) 351-5633.
Sincerely, _,,,,,,,,~
_-~ti. OF 1'}\"
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DOUG P.l'OlKOWSK;.~'
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Senior Vice Pre Mft...p~fl' 4".f.~...~4<<;~
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Mark W. Kawalek, P.E.
President
Time Spent: 6 hours over project duration
Distribution: (I) Client
(I) City of Coppell- Attn: Mr. Eric Greaser
(I) Jamail & Smith - Attn: Mr. Randy Jones
Shared\projects\cmt\ City of Coppell\Fire Station No.1 \Reports\Letters\0268-00 14B.112508.doc