B. The size of the geosynthetic sample to be obtained from each material type shall
be determined by the needs of the test to be performed, and be no small than a
3-foot long piece cut along the length of the geosynthetic roll.
C. Soil components used in the laboratory testing program shall be obtained from
the borrow source or from soil stockpiles to be utilized in the construction of
the soil components during construction.
2.02 INTERFACE STRENGTH TESTING REQUIREMENTS
A. The interface shear strength test results shall equal or exceed the peak and post-
peak strengths values listed in the table below.
Interface Shear Strength
Normal Stress Peak Post Peak
(psi) (psf) (psf)
22 854 448
44 1708 896
89 3416 1792
The following interfaces shall be tested in a soaked condition:
a. Drainage Geeocomposite/Geomembrane;
b. |Geomembrane/GCL; and
c. | Geomembrane Liner/Screened Till.
For the Geomembrane Liner/Screened Till interface, the Screened Till
shall be compacted to 95 percent of the maximum density as determined
by ASTM D698 at a water content one to two percent above the optimum.
The recompacted Screened Till shall be allowed to condition for no less
than 36 hours prior to testing.
For geosynthetic/soil interface tests (including those with GCL), the
geosynthetic shall be placed in the testing device first, and the soil
placed/compacted above. Care shall be take not to damage the underlying
geosynthetic.
The Geomembrane/GCL test setup shall be hydrated for 24 hours under a
normal stress of 5 psi. After soaking, the sample should be loaded to the at
least 10 psi and allowed to consolidate for 48 hours prior to testing.
Maximum shear displacement rates shall be as follows:
Drainage Sand/Drainage Geocomposite - 0.04 in./minute
Drainage Geocomposite/Geomembrane - 0.2 in./minute
Geomembrane/Geosynthetic Clay Liner (GCL) - 0.04 in./minute
GCL/Drainage Sand - 0.04 in./minute — 0.04 in./minute
Geomembrane/Screened Till - 0.04 in./minute.
eno gp
File No. 3066.09
Interface Strength Testing 02560 - Page 2 of 3 December 2017
