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., I LEMSMILL-MERKEMMOF'F, INC. "'��• 3.2 SOIL SIEVE ANALYSIS As previously discussed, representative discrete soil samples were taken from the continuous core of soil boring SBI to verify the classification of the soil samples by the Unified Soil Classification System (USCS) . The results of the sieve analysis are included in Appendix C and are summarized in Table 1 : Table 1 Weber Point Sieve Analysis Results Sample Depth Number (Ft) % Gravel 9. Sand 7. Clay Soil Type SBI-13 13.0 0.0 15.9 84.1 Brown Lean Clay with sand (CL) SBI-23 22.6 0.2 21 .5 78.3 Brown Lean Clay with sand CL S81-25 25.4 2.0 5.1 92.8 Brown Fat Clay CH SBI-30 30.4 0.0 7.6 92.4 Gray Lean Clay CL SBI-35 35.2 0.0 15.6 84.4 Gray Lean Clay with sand (CL) The soil composition and soil types show that the iithoiogy at this site above 35 feet is predominately clay. The percentage of clay in the samples ranged from 78% to 92% with inversely corresponding sand composition ranging from 22% to 89.. Gravel -sized sand was found in only two of the samples at 2% or less composition by weight. The clays varied from brown to gray and were primarily lean clays with one sample classified as a fat clay. The field geologist collecting the samples noted that some of the clays appeared silty. Figure 4 shows a photograph of the continuous core for soil boring SBI and illustrates the color and texture changes described above. 3.3 GEOLOGIC CROSS-SECTION An interpretive geologic cross-section was prepared based on geologic information obtained from the soil borings and monitoring well borings. Figure 3 shows the locations of LH's soil borings, monitoring well borings and the cross-section lay-out, A-A' . Cross section A-A' is a northwest-southeast cross-section including borings MW2, SB3, 564, and S81 and is shown in Figure 5. - � 10