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- . •, - <br />The Soil Liner Fill material meets the permeability specification of <1x10~6 cm/sec. The test <br />results are submitted as part of Attachment 1. Test results ranged from 5.7 x lt7' to 6.3 x 10'8 <br />cm/sec for the Soil Liner Fill compacted to 95 percent of standard Proctor and a moisture <br />content of 3 percent dry of optimum. <br />The material has a cation exchange ratio of 11.8 meq/100 gm, which demonstrates its non- <br />expansive character. This is similar to the cation exchange ratios of the other two materials. <br />The grain size distribution is only very slightly different than the two currently in the Technical <br />Specifications. It is repeated from the Attachment in the following table. Only the percent <br />passing the three smaller screens changes from the additional specification submitted on January <br />9, 1996. Slightly less may pass the k4, /i40, and N200 screens. The minimum plasticity index <br />is slightly lower than accompanying the January 9 submission. Comparison to the 1994-5 Soil <br />Liner Fill grain size distribution, this additional matrix still has more passing these three screens <br />(1/4, f140, and N200). <br />ADDITIONAL 1996 SOIL LINER FILL <br />GRAIN-SIZE DISTRIBUTION <br />Slave Sizc Parcam Passing <br />2-inch 100 <br />7/3 inch 75-100 <br />3/8 inch 70-100 <br />p4 55-100 <br />pao Soao <br />p?00 30-60 <br />PI IS (min) <br />Effectively, this grain size distribution and PI, along with the other two grain size distributions <br />in the Technical Specifications are beginning to describe a range in grain size distributions and <br />plasticity limits that provide Soil Liner Fill that meets the design permeability criterion. <br />The interface shear test produced acceptable results, that is, results were within the envelope of <br />the range of cohesion and friction angles that provides pseudo-static factor of safety of 1.0 or <br />higher. The tests with this third Soil Liner Fill material with the textured LLDPE (textured side <br />down) material showed a residual cohesion of 2055 psf and an interface shear angle of 16°. <br />This represents the Drain Cover Fill-LLDPE synthetic liner-Soil Liner Fill interface, where the <br />Soil Liner Fill is this additional material. With our letter of January 19, 1996, we submitted the <br />results of interface shear that demonstrated cohesion of 410 psf and an internal friction angle of <br />18° for the Drain Cover Fill-HDPE Synthetic Liner-Soil Liner Fill interface (see Attachment 6 <br />to that letter). This combination was shown to have apseudo-static factor of safety of equal to <br />or greater than 1.0. In our subsequent letter of February 12, 1996, we further demonstrated <br />cohesion of 865 psf and an internal friction angle of 18° for the Drain Cover Fill-LLDPE <br />Synthetic Liner-Soil Liner Fill interface. This also provided apseudo-static safety factor of <br />2 <br />