ARCHIVED REPORTS_2010 - Laserfiche WebLink

Home Browse Search

Aft GEOMEMBRANE PUNCTURE RESISTANCE AGAINST CRUSHED ROCK MODULES 5 THROUGH NORTHCOUNTY El 1.0 Introduction The final grading plan prepared as part of the expansion of the North County Recycling Center and Sanitary Landfill shows a maximum elevation of 320 feet. This would results in a maximum waste height of approximately 255 feet above the liner system with a relatively large vertical stresses on the liner system. Crushed stone may be used for the leachate collection and removal system (LCRS) in the future Modules 5 through 11. The crushed stone is likely to be obtained from the Foothill Sanitary Landfill site. Therefore, the puncture resistance calculation presented herein was performed to determine the feasibility of using crushed stone for LCRS. It is assumed that crushed stone with a uniform size of '/s inch would be used. To provide protection against puncture of the 60 -mil HDPE geomembrane from the crushed stone, a geotextile cushion layer would be required above the geomembrane before placing the crushed stone. A non -woven geotextile with a minimum mass per unit area of 16 ounce per square -yard (oz/yd2) is assumed. P' that can be tolerated b a According to Koerner (1998), the allowable pressure( ��ow) y geotextile layer subject to a protrusion of effective height H is given by, Parrow = [50+0.00045 1 1 (Eq. 1) H MFS . MFpo .MFA RFcR RFcaD where, P'�jio,u = Allowable pressure (in kPa) M = Mass per unit area of the geotextile cushion (in g/m2) H = Effective protrusion height (in meters) MI's = Modification factor for shape of protrusion MFpD = Modification factor for packing density MFA = Modification factor for arching FCR = Partial factor of safety for creep FCBD = Partial factor of safety for chemical and biological degradation For a 16-oz/yd2 (i.e., 540 g/m2) non -woven needle -punched geotextile, M = 540 g/m2 N: IGEOTECHNICALWCRC&SL-20071Punture-ResistanceUfodules 5-111Crushed Rock doc Page 1 of 3