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11 <br />Shaw Environmental, Inc. <br />NORTH COUNTY RECYCLING CENTER AND SANITARY LANDFILL, MODULE 1 <br />CHECK OF EXISTING LEACHATE COLLECTION PIPES <br />USING THE IMPROVED PIPE LOADING CALCULATION <br />slots/perforations: <br />width or diameter d = 0.25 inch <br />number of slots/row/ft n=1 1 <br />pipe modulus of elasticity <br />Initial Ep = 120000 psi <br />Long-term (50 year) 22000 psi <br />Compressive yield strength <br />Initial PA = 3000 psi <br />Long-term (50 year) 1440 psi <br />B. Loading on the Pipe <br />The loading based on the maximum waste height is computed below: <br />2.0 ft. final cover @t8100 <br />pcf 230 psf <br />1.0 ft. intrm cover @ pcf 110 psf <br />145.0 ft. solid waste @ pcf 11,600 psf <br />11,940 psf <br />a = 82.9 psi <br />Total load with correction for pipe slots/perforations, <br />6 <br />n.dI12) <br />a, = 84.7 psi <br />C. Bedding Material Properties <br />Construction plans show that a sand bedding ,was used below the pipes. <br />deflection lag factor Lc= <br />bedding constant K = 0.11 <br />modulus of soil reaction E, = see below <br />Replace E,, by M,. (based on McGrath, 1998a) <br />Based on McGrath (I 998a), replace modulus of soil reaction (E,) with stress <br />dependent constrained modulus (M,). The figure from Koragappa (2005) <br />presented on next page shows variation of M, with a, for typical bedding materials. <br />N:\GEOTECHNICAL\NCRC&SL-2007\Pipe-Loading\Module 1&2\Modu1e1&2_31nchPipe_ImprovedMethod_148ft.xls Page 2 of 6 <br />