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<br />1 <br /> <br /> <br />t <br /> <br />and was completed in late October 1990 with the exception of the slope grading and access road <br />construction. <br />Once stripping of the foundation was completed, the foundation was leveled using cut and fill <br />techniques. The foundation was shaped using Type 4, random fill. This random fill material was <br />borrowed primarily from the north abutment shaping operations. The ridge on the north abutment <br />was excavated due to the irregular steep slopes which did not lend themselves to the liner <br />installation. SRK as-built Drawing No. 14711-106 is representative of the final grade of the main <br />embankment foundation after the shaping and grading was completed (the actual excavation <br />elevations are approximately 1-ft below the depicted elevations). <br />Once the foundation was shaped and proof rolled 1 ft of Type 3 material was placed on the grade. <br />' This material was moisture conditioned, as required, and compacted to a 95 percent density based <br />on a standard proctor (ASTM-D698). Insitu permeability testing was also performed on the <br />1 material using the BAT permeability testing method. These tests were performed oh approximately <br />each 1.5 acres of foundation prepared for liner installation. The results of the test are summarized <br />in Appendu A of this report. <br /> <br /> <br />1 <br /> <br />1 <br />1 <br /> <br />1 <br /> <br />1 <br />During this stage of the project it was observed that most of the silt deposits on site had small <br />angular gravels within the gradation. These small gravels were not removed by the normal rock <br />raking and compaction efforts. In addition, many of the gravels were being turned up as foot and <br />equipment traffic preformed the liner deployment activities. Due to the small size and quantity of <br />the gravels the following procedure was developed to minimsp the amount of gravel particles <br />encountered at the silt to liner interface; <br />Silt material, containing small gravel particles were placed on the bottom 9 Ines of the liner <br />foundation layer. These materials were moisture conditioned and compacted to the specified <br />density of 95 percent of the maximum Proctor density. The lower silt layer (with gravels) was then <br />capped with very clean fine grained silts from selected borrow sources. The clean fine grained silts <br />were rock raked and smooth drum compacted leaving a uniformly smooth surface relatively free of <br />small gravels which could damage the synthetic liner materials. <br />This technique proved to be an effective means of protecting the liner from the sntall gravels and <br />was utilized for the remainder of the project on the finer foundation preparation gperations. <br />Gundle was mobilized to the site on July 21, 1990 to begin installing liner on the foundation. On <br />July 26, 1990 Gundle began liner installation on the upper end of the main embankment drain <br />blanket channel. On September 5, 1991 Gundle wmpleted the 40 mil VLDPE liner installation on <br />9 <br />1 <br />