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Shaw Environmental, Inc. <br />NORTH COUNTY RECYCLING CENTER AND SANITARY LANDFILL, MODULE 4 <br />CHECK OF EXISTING LEACHATE COLLECTION PIPES <br />USING THE IMPROVED PIPE LOADING CALCULATION <br />slots/perforations: <br />width or diameter d=j 0.18 inch <br />number of slots/row/ft n=1 <br />pipe modulus of elasticity <br />Initial Ep = 120000 psi <br />Long-term (50 year) F _220001 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 @ 115 pcf 230 psf <br />1.0 ft. intrm cover @ 110 pcf 1 10 psf <br />238.0 ft. solid waste @ 90 pcf 21,420 psf <br />21,760 psf <br />6 = 151.1 psi <br />C <br />Total load with correction for pipe slots/perforations, <br />6 <br />6i = <br />(1 — n.d/12) <br />ai = 155.8 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 6i for typical bedding materials. <br />N:\GEOTECHNICALWCRC&SL-2007Tipe-Loading\Module4\Module4_41nchPipe_ImprovedMethod_241ft.xls Page 2 of 6 <br />