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January 15, 2008 <br />Page 22 <br />6amb (s + mb°y3n )a-1 <br />a-1 <br />arm =sin 12(1 + a)(2 +a) +6amb(s + Q3n ) <br />?." <br />Ord [(1 + 2a)s + (1- a)mbc3n Is + mbc3n )a-1 (Eqn. 6) <br />Crm = <br />Q+a)(2+a) 1+(6amb(s+mbO73n)a-1)x((1+aX2+a)) <br />where 63n = a3maxlaci .and 63,nax is the upper limit of confining stress over which the strength <br />criteria are considered. The equivalent UCSr,,, value for the rock mass is given by Equation 7. <br />UCS 6 Q X (Mb + 4s - a(mb - 8s)Xmb 14 + s)a-1 (Eqn. 7) <br />rm = cm = ci 2(1 + a)(2 + a) <br />These equations were used to estimate the in situ rock mass strength and deformation <br />parameters for cohesion, C„n, friction, orn, tensile strength, T,,,,, and UCSrn for each of the <br />23 rock layers documented in Table 1 of the G-Pit Landslide Stability Report 4 Of most <br />importance for the stability analysis of the hillside is the weakest layers; that is, the weak L-Roof <br />mudstone and Q-Floor mudstone. The properties used in the stability analyses were as follows. <br />• Density, yr,n = 135.7 pcf <br />• Young's Modulus, Ern,= 1.3X106 psi <br />Poisson's Ratio, v,n,= 0.40 <br />• Friction Angle, l6rn,= 3.41 <br />• Cohesion, Cr,,, = 1.7 psi <br />Tensile Strength, Trn,= 0.11 psi) <br />Bedding Friction Angle, Oj = 18.3° -> 5° <br />• Bedding Cohesion, Cj= 0.25 --3- 0 psi <br />Bedding Tensile Strength, T = 0 psi <br />Agapito Associates, Inc.