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C CORNERSTONE <br />EARTH GROUP <br />average value correlating to dense granular soils. The soil strength parameters used in our <br />analysis are summarized in Table 2. <br />Table 2: Summary of Soil Strength Properties (Total Stress Parameters) <br /> Total Cohesion Friction <br />Soil Description Unit Weight fps Angle <br /> (p (de rees <br />Upper Sand/Gravel 130 0 35 <br />UpperSilUClay 125 1,800 0 <br />Gravel 135 100 40 <br />Alluvium 130 1,500 25 <br />4.6.4 Results of the Analysis <br />We computed the minimum static and seismic factors of safety with respect to sliding for Cross <br />Section A-A' shown in Figure 4, which was considered to represent the steepest slope condition <br />adjacent to the proposed development. The results of our analyses are summarized in Table 3, <br />C and indicate that the resulting factors of safety are above minimum acceptable levels of 1.1 and <br />1.5 for static and seismic loading conditions. <br />Table 3: Results of Slope Stability Analyses <br /> <br />i <br />i Factor of Safety <br />Descr <br />pt <br />on <br />Static <br />Pseudo-Static* <br />Low-Water 1.9 1.2 <br />High-Water 2.0 1.1 <br />*Seismic coefficient = 0.2 <br />The evaluation of localized stability of future buttress fills that may be placed on the quarry slope <br />on behalf of Hanson Aggregates and Zone 7 Water Agency was beyond the scope of this <br />investigation. Based on our review of the conceptual cross section from the Geocon report; <br />however, in our opinion, the placement of a buttress fill on the existing slope will not impact the <br />global stability of the quarry slope. <br />4.6.5 Siope Deformation Analysis <br />Because of the proximity of the proposed residential development to the top of the existing <br />quarry slope, we performed a preliminary review of the potential for slope deformation during <br />Ponderosa Active Adult Community Page 9 <br />132-2-1 <br />