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13 Static Soil Properties Compressibility. The potential compressibility of the surface materials due to loading was estimated from blow count data, soil type, and test results. The surficial sands, to about 14-foot depth, are judged to be moderately compressi- ble. The presence of glass complicates the assessment of compressibility of the upper sand layer and suggests that differential settlements due to loading are to be expected at the site. The results of a consolidation test on a sample (appar- ently with no glass) of the surface one foot show moderate compressibility and collapse characteristics. If the upper 15 feet of soils are (a) densified in situ, (b) removed, blended, and then recompacted, or (c) replaced with compacted import fill materials, the differential compressibility will be reduced. The compressibility of the stiff, lean clay was evaluated by performing three consolidation tests. The tests suggest that the clay is slightly overcon- solidated with respect to the present overburden pressure. The test results suggest that the Overconsolidation Ratio (OCR) decreases from about 2 to 2-1/2 near the top of the stratigraphic sequence to about 1-1/2 to 2 near the base of the clay. Provided that the imposed loads transferred to the clays do not exceed the preconsolidation pressure of the clay, settlements due to compression of the clay sequence should be minimal. Expansion. The expansion potential of the surface sands is judged to be low. Expansion of clays, if any, is not expected to impact the design since the clays are below the 14-ft depth. Shear Strength. The shear strength of the shallow materials was estimated from blow count and direct shear test data. Loose to medium dense zones with relatively low blow count in the upper 14 feet of soil are relatively weak. An internal friction angle of between 23.5 and 39.5 degrees was measured in three direct shear test samples of the near-surface, loose to medium dense sand. Where glass is the predominant matrix material, the shear strength is difficult to assess. If loads break individual glass fragments or cause a rearrangement of point to point contacts between glass fragments, a low strength would result. Otherwise, the strength is probably relatively high since the individual glass fragments are angular and non-compressible. A high strength is expected for silty sands if compacted to criteria for structural fill. The effect of mixing 20 percent glass fragments with the silty sand was evaluated by conducting a multistage, consolidated undrained triaxial test on a sample compacted to 90 percent relative compaction, relative to the 1144A/CC-13 McClelland