A CPT test was conducted at a site that consists of normally consolidated sand with some interbedded silts. The CPT profile is approximated into uniform soil layers with constant cone-bearing, as shown in Table 01. The modulus of elasticity for the soils can be approximated by E= 3.5qc. The groundwater table is at a depth of 2.5m below the ground surface, and the total unit weight y=18 kN/m³ above and y=18.81kN/m³ below the GWT. A 30m x 2.5m strip footing founded at a depth of 2m in this soil has to carry a load of 15MN. Use Schmertmann's strain influence factor method to determine the settlement of this footing a) Immediately after, and b) 50 years after construction.

Following table presents information for a fine-grained soil: Current effective stress (kPa) Current void ratio of the soil Overconsolidation Ratio (OCR) Compression index (Cc) Re-compression index (Cr) 30 0.96 7.06 0.18 0.06 Determine the void ratio of the soil at the preconsolidation pressure.

A certain saturated sand (S = 100%) has a moisture content of 27.9% and a specific gravity of solids of 2.61. It also has a maximum index void ratio of 0.90 and a minimum index void ratio of 0.33. Compute its relative density and classify its consistency. (Table on the right) Solution: Given the values of mmoisture content, specific gravity and degree of saturation, the void ratio can be estiamted as: e = Thus the relative density is found to be Dr = • According to the table, the soil is classified as %; soil. TABLE 3.3 CONSISTENCY OF COARSE-GRAINED SOILS AT VARIOUS RELATIVE DENSITIES (data from Lambe and Whitman, 1969) Relative Density, D,(%) 0-15 15-35 35-65 65-85 85-100 Classification Very loose Loose Medium denseª Dense Very dense "Lambe and Whitman used the term "medium," but "medium dense" is better because "medium" usually refers to the particle size distribution.