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COVER PLACEMENT <br />10.1 <br />The final thickness of soil cover on the GCL varies with the application. A minimum ~ <br />cover layer must be at least 1 foot (300 mm) thick to provide confining stress to the GCL, <br />eliminate the potential for seam separation and prevent damage by equipment, erosion, etc. <br />10.2 Cover soils should be free of angular stones or other foreign matter that could damage the GCL. <br />Cover soils should be approved by the Engineer with respect to particle size, uniformity, and <br />chemical compatibility. Consult CETCO if cover soils with high concentrations of calcium <br />(e.g., limestone, dolomite, gypsum, seashell fragments) are present. <br />10.3 Recommended cover soils should have a particle size distribution ranging between fines and <br />1 inch (25 mm), unless a cushioning geotextile is specified. <br />10.4 Soil cover shall be placed over the GCL using construction equipment that minimizes stresses on <br />the GCL. A minimum thickness of 1 foot (300 mm) of cover soil should be maintained between <br />the equipment tires/tracks and the GCL at all times during the covering process. In frequently <br />high-traffic areas or roadways, a minimum thickness of 2 feet (600 mm) is required. <br />10.5 Soil cover should be placed in a manner that prevents the soil from entering the GCL overlap <br />zones. Soil cover should be pushed up slopes, not down slopes, to minimize tensile forces <br />on the GCL. <br />10.6 When a textured geomembrane is installed over the GCL, a temporary geosynthetic covering <br />known as a slip sheet or rub sheet should be used to minimize friction during placement and to <br />allow the textured geomembrane to be more easily moved into its final position. <br />10.7 Claymax must be covered with a geomembrane and/or 12" (300 mm) of cover material within <br />8 hours of deployment to prevent the potential for shrinkage by desiccation. <br />r <br />10.8 Cyclical wetting and drying of GCL covered only with geomembrane can cause overlap separation. <br />Soil cover should be placed promptly whenever possible. Geomembranes should be covered <br />with a white geotextile and/or operations layer without delay to minimize the intensity of <br />wet-dry cycling. If the GCL is covered only with a geomembrane for an extended period, <br />longitudinal seam overlaps must be increased to 12" (300 mm). <br />10.9 To avoid seam separation, the GCL should not be put in excessive tension by the weight or <br />movement of textured geomembrane on steep slopes. Check with project engineer for the <br />potential for GCL tension to develop. <br />FIYDRATION <br />11.1 Hydration is usually accomplished by natural rainfall and/or absorption of moisture from soil. <br />However, in cases where the containment of non-aqueous liquid is required, it may be necessary <br />to hydrate the covered GCL with water prior to use. <br />11.2 If manual hydration is necessary, water can be introduced by flooding the covered lined area or <br />t <br />~. using a sprinkler system. <br />~~~ <br />BENTOMAT/CLAYMAX Installation Guidelines 15 of 15 <br />