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9 July 1997 - <br /> Direct Shear Friction Tests <br /> Forward LF <br /> NSC Job##97061 C <br /> TESTING EQUIPMENT, MATERIALS AND PROCEDURES <br /> Summary of Materials, Tests and Results <br /> National Seal Company received two 5 gallon containers of site-soil to be included in direct shear testing <br /> for the Forward Landfill, WMU D-97 project. Other materials to be included in the testing were NSC <br /> 60-mil single sided textured HDPE geomembrane (S06F307A-4F2308B03), and Bentofix NW GCL <br /> (22119). 1n addition, a peel test was performed on the GCL sample in accordance with ASTM D 4632 - <br /> 91, Standard Test Method for Grab Breaking Load and Elongation of Geotextiles. The following <br /> profiles.were evaluated under normal stresses of 4000, 8000 and 13000 psf (the high normal stress <br /> desired for this project of 15000 psf is not attainable on NSC's shear device): <br /> 1. Textured side of membrane/Site-soil <br /> 2. Textured side of membrane/GCL/Site-soil <br /> Below is a summary of the tests and the results. <br /> Profile Peak Angle Residual Angle <br /> Test Series (degrees) (degrees) <br /> Textured side of membrane <br /> 1 Site Soil 30.1 27.5 <br /> Textured side of membrane Left to the <br /> 2 GCL 21.8 discretion of the <br /> Site-soil engineers <br /> Peel Test <br /> Bentofix NW; Average of 3 specimens <br /> 39.4 lbf <br /> Test Apparatus <br /> • National Seal Company's test apparatus was manufactured by GeoSyntec Consultants. The upper box <br /> measures 12" x 12" x 3". The length of the lower box is 14". This allows the 12" x 12" test area 2" of <br /> displacement. An electric motor supplies the shearing force and displaces the lower box relative to the <br /> upper stationary box. The upper box is held stationary by a load cell which in turn measures the shear <br /> stresses. In these particular tests the normal stresses were applied by regulated air. <br /> Preparation of Specimens <br /> The soil for test series 1 was to be compacted to a relative compaction of 90% at a water content of 2 to 5 <br /> percent above optimum (modified Proctor, ASTM D 1557). The Proctor analysis was provided with the <br /> interface shear strength testing protocol. The maximum dry density was 118.9 pcf, and the optimum <br /> water content was 13.0%. A dry density and moisture content of 107.01 pcf and 16.92% respectively, <br /> were used. The soil was compacted into the bottom box of the shear device. The membrane was <br />