Laserfiche WebLink
For the proposed '/2 inch crushed stone, assume a maximum size of '/a inch, to be <br />conservative. The effective protrusion height can be assumed to be half the maximum <br />stone size; i.e., <br />H = 0.5 x 0.75 inch = 0.375 inch = 9.525 mm = 0.009525 m <br />For angular stone, <br />MFS = 1.0 <br />For packed stones, <br />MFpD =0.5 <br />Because waste to be placed above the geotextile is deep, maximum arching is anticipated, <br />therefore, <br />MFA = 0.5 <br />The FSCR depends on the mass per unit area of the geotextile. Assuming a 16 oz/yd2 <br />(540 g/m2) geotextile, <br />FCR 1.5 <br />40 Assume, a factor of safety of 1.5 for chemical and biological degradation, <br />FCBD = 1.5 <br />Substituting the above values in eq. 1, <br />50+0.00045 540 1 1 = 4,850kPa <br />atr°w — (0.009525)' (1.0) (0.5) (0.5) (1.5) (1.5) <br />Assuming a maximum waste height of 255 feet and a waste unit weight of 90 pcf, the <br />actual pressure (P.wal) on the geotextile is, <br />P.tual = (255 ft) x (90 lb/ft) = 22,950 lb/ft =1,100 kPa <br />The factor of safety (FS) against puncture is given by, <br />FS = Palmw = <br />Pactual <br />4,850 = 4.4 <br />1,100 <br />Since the computed factor of safety is greater than the recommended (Koerner, 1998) <br />minimum factor of safety of 3, a 16-oz/yd2 geotextile (non -woven, needle -punched) <br />.40 would be adequate to provide the necessary puncture protection. <br />N.IGEOTECNNICALINCRC&SL-200APunture-ResistancelModules 5-111 Crushed Rock doc Page 2 of 3 <br />