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k'q KLEINFELDER I•. i performed on any of the gravelly materials from this site, as explained in Section 1V of this report. I However, unconfined compressive tests were performed on two samples obtained from the k adjacent existing Granite pit. For this reason, our analyses are conditional on tests being performed during initial excavation-of the quarry to confirm strength parameters and soil type. The slope stability analyses were performed using the computer program SLOPE/W. SLOPE/W uses the limit equilibrium theory to compute the factor of safety of earth and rock slopes using the following methods: Ordinary or Fellenius, Bishop's Simplified, 3anbu's Simplified, Spencer, Morgenstern-Price, Corps of Engineers, Lowe-Karafiath, General Limit Equilibrium, and Finite Element Stress. Based primarily on the soil conditions and our experience with large existing cuts in similar materials, we anticipate that a wedge block or partially circular type failure would be appropriate. In order to evaluate other possibilities, we have also evaluated numerous circular failure conditions as well. Summarized on in Table 1 below are the soil properties for the four basic soil groups encountered in the test borings. As previously stated, the strength properties shown were based on Laboratory tests on relatively undisturbed block samples, laboratory tests on samples obtained from our borings, and test results of similar soils in the area. t TABLE 1 SOIL PROPERTIES An of Internal MostTIlt Soil Type Ftiefi0I1 (degrees) Cohesidn_(ps fl Weight{P Cemented Sand and gravel 36 900 130 Silty Clay 24 500 120 Sandy clay/ Silty Sand 25 350 120 Reclaimed Slope 25 500 115 The effect of ground shaking on the computed factors of safety was evaluated by applying a pseudo-static seismic load. The practice in this area is to utilize a mean peak ground acceleration corresponding to a maximum probable earthquake (10 percent chance of exceedance in 50 years) roughly approximated by a pseudo-static analysis. Based on the proximity of the nearest faults and estimates of maximum probable earthquakes, it is our opinion that a 0.15g design acceleration value is appropriate for this study. Circular arc failure surfaces were analyzed using the Bishop's Simplified method. This method utilizes the slope configuration, unit weight and shear strength properties of the exposed materials, i and internal forces due to water pressures. After a potential failure surface has been assumed, the f soil mass located above the failure surface is divided into a series of vertical slices. Forces acting . I 20-1 108-181201 SK096 Page 4 of 7