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File No. 20-1008-49 KLEI N FELDER December 22, 1994 Permeability No. Northing Easting k (cm/sec) 29 1700 3120 2.9x 10'' 30 3150 1675 5.4x10' ANALYSIS AND CONCLUSIONS The test pad, which met the 1x10' cm/sec permeability requirement using the SDRI, was compacted at 95 percent relative compaction and had an average moisture content of 0.9 percent above the optimal moisture content. Approximately 20 percent of the moisture content tests were equal to or greater than 2 percentage points above the optimum moisture content. The average differential moisture content (moisture content minus optimum moisture content) for measurements less than 2 percentage points above the optimum moisture content was 0.54 percent. The SDRI permeability on the test pad (single lift area) was approximately 4x10$cm/sec. Two block samples cut from the same test pad and tested for permeability in the laboratory (ASTM D-5084) had permeabilities equal to 2x10$ and 5x10 cm/sec respectively. This indicates that for this project, there should be a very close correlation between the actual permeability (as measured by the SDRI) and laboratory permeabilities (meaning that the laboratory permeabilities give a good indication of what the actual field permeability is). Seven hundred three nuclear density and moisture content tests were performed during the construction of the final landfill cap barrier layer. All of these measurements were greater than or equal to the 95 percent relative compaction standard, with the exception of the side slopes which were greater than or equal to the 90 percent relative compaction standard. Approximately 52 percent of the tests showed compaction at moisture contents in excess of two percentage points above the optimum moisture content. This exceeds that observed in the test pad (20%). The average differential moisture content (moisture content minus optimum moisture content) for those measurements that were less than 2 percentage points above optimum was 0.46 percent. This is very close to the corresponding measurement made on the test pad (0.54 percent). Seventy-four (74) percent of the sand cone moisture contents performed were greater than 2 percent over optimum with an average moisture content of 1.9 percent over optimum. According to the ASTM 1557 "A" testing procedure, optimum moisture content for compaction curves may vary up to 15 percent of the mean. In other words, for an average optimum moisture content of 12 percent, it may vary by about 2 percent. Noting the allowable testing variability, all of the moisture contents met project specifications. Thirty laboratory permeability samples were collected from the barrier layer and all had permeabilities equal to or less than 7.9x10-' cm/sec. This meets and exceeds the design standard of 1x10 cm/sec. Since the test pad shows that the SDRI and laboratory Copyright 1994 Kleinfelder,Inc. Page I I of 12