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Shaw Environmental, Inc. <br />NORTH COUNTY RECYCLING CENTER AND SANITARY LANDFILL, MODULE S 5 THROUGH 11 <br />DESIGN OF LEACHATE COLLECTION PIPES <br />USING THE IMPROVED PIPE LOADING CALCULATION <br />slots/perforations: <br />width or diameter d=1 0.18 inch <br />number of slots/row/ft n = <br />pipe modulus of elasticity <br />Initial Ep = 120000 psi <br />Long-term (50 year) 22000 psi <br />Compressive yield strength <br />Initial PA =1 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 />F__250-7 ft. final cover@ 115 pcf 230 psf <br />1.0 ft. intrm cover @ ll0 pcf 110 psf <br />252.0 ft. solid waste @ 90 pcf 22,680 psf <br />23,020 psf <br />a = 159.9 psi <br />Total load with correction for pipe slots/perforations, <br />6 <br />6i = <br />0 — n.d/12) <br />a, = 164.8 psi <br />C. Bedding Material Properties <br />Construction plans show that a gravel bedding below and around the pipes. <br />deflection lag factor Lt = 1 <br />bedding constant K = 0.083 <br />modulus of soil reaction E, = see below <br />Replace E,. by M,,. (based on McGrath, 1998a) <br />Based on McGrath (1998a), 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 />NAGEOTECHNICA LWCRC&SL-2007\Pipe-Loading\Modu les 5-I IW15-11_41nchPipe_SDR13.5_255ft.xls Page 2 of 6 <br />