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ame0 <br />the CERTIFYING ENGINEER to facilitate hydration of the GCL upon placement. At completion <br />of this activity, no wheel ruts, footprints, or other irregularities shall exist in the subgrade. <br />Protrusions extending more than one -half inch (0.5 in) from the surface shall be either removed, <br />crushed, or pushed into the surface with a smooth -drum compactor. <br />3.06 SEAMING <br />C. On a continuing basis, the CQA Monitor and INSTALLER shall observe acceptance of the <br />subgrade prior to GCL placement. Thereafter, it shall be the INSTALLER's responsibility to <br />indicate to the CQA Monitor any change in the condition of the subgrade that could cause the <br />subgrade to be out of compliance with any of the requirements listed in this Section. <br />3.05 ANCHORAGE <br />A. The end of the GCL roll shall be placed in an anchor trench at the top of the slope or an equivalent <br />runout design shall be utilized. When utilizing an anchor trench design, the front edge of the trench <br />should be rounded so as to eliminate any sharp corners. Loose soil should be removed from the floor <br />of the trench. The GCL should cover the entire trench floor but does not extend up the rear trench <br />wall. <br />A. The GCL seams are constructed by overlapping adjacent panel edges and ends. Care should be taken <br />to ensure that the overlap zone is not contaminated with loose soil or other debris. <br />B. Longitudinal seams should be overlapped a minimum of six (6) inches for Bentomat ST, or per the <br />MANUFACTURER's recommendations for an approved equivalent GCL. If the GCL is <br />manufactured with a grooved cut in the nonwoven geotextile that allows bentonite to freely extrude <br />into the longitudinal overlap, then no bentonite - enhanced seam is required for this overlap. If the <br />GCL does not have a grooved cut in one of the nonwoven geotextiles in the longitudinal overlap, <br />then longitudinal bentonite - enhanced seams are required as described below. <br />C. End -of -roll overlapped seams should be constructed with a minimum overlap of twenty-four (24) <br />inches for Bentomat ST, or per the MANUFACTURER's recommendations for an approved <br />equivalent GCL. Seams at the ends of the panels should be constructed such that they are shingled in <br />the direction of the grade to prevent the potential for runoff flow to enter the overlap zone. <br />D. Bentonite - enhanced seams are constructed between the overlapping adjacent panels described above. <br />The underlying edge of the longitudinal overlap is exposed and then a continuous bead of granular <br />sodium bentonite is applied along a zone defined by the edge of the underlying panel. A similar bead <br />of granular sodium bentonite is applied at the end -of -roll overlap. The granular bentonite shall be <br />applied at a minimum application rate of one quarter pound per lineal foot (0.25 lb /ft). <br />3.07 DETAIL WORK <br />A. The GCL shall be sealed around penetrations and embedded structures embedded in accordance with <br />the GCL MANUFACTURER recommendations. <br />B. Cutting the GCL should be performed using a sharp utility knife. Frequent blade changes are <br />recommended to avoid damage to the geotextile components of the GCL during the cutting process. <br />Section 02776.1 Page 6 of 7 <br />Geosynthetic Clay Liner (GCL) <br />June 19, 2012 <br />Revision 1 <br />