2012-02-28_REVISION - M1980244 (89)

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2.3 Geosvnthetic and Soil Materials The geosynthetic and soil materials used in the testing program are presented in Appendix A. The geomembrane materials were provided to GeoSyntec by CC &V. The three site soils were obtained from the project site by CC &V and delivered directly to GeoSyntec for testing. 2.4 Test Configuration and Procedures for Interface Direct Shear Tests The configuration of the test specimens and the specific test procedures used to conduct each of the interface direct shear tests are presented in Appendix B. GeoSyntec understands that the test procedures and test conditions were selected by Mr. Mandziak of CC &V to model anticipated field conditions. 3. TEST RESULTS 3.1 Failure Modes For Test Series 1, shear failure (sliding) occurred between the drain cover fill and the geomembrane. For Test Series 2 and 3, sliding occurred between the clay borrow soil liner (SLC -4) and the textured side of the geomembrane. 3.2 Data Presentation 6 2000 GeoSyntec Consultants For each of the interface direct shear tests, the total - stress shearing resistance was evaluated for each applied normal stress. The test data were plotted on a graph of shear force versus horizontal displacement. The resulting plots are presented in Appendix C. The peak value of shear force was used to calculate the peak shear strength. The large displacement shear strength (tL) was calculated by using the shear force measured at the end of each test. No area correction was used when computing normal and shear stresses because each test was performed using a constant effective sample area (i.e., the area of the lower shear box was larger than that of the upper shear box). The calculated shear strengths are plotted on a graph of shear stress versus normal stress. The results were used to evaluate total - stress peak and large displacement shear strength envelopes. A straight line was drawn from the origin through the data points GLI1 126 /SGI00011. DOC 2 00.02.25