2.13 The soil profile at a site is shown in Figure P2.13. The moist and saturated unit weights of the sand are 17.0 kN/m2 and 20.0 kN/m3, respectively. A soil specimen was taken from the middle of the clay layer and subjected to a consolidation test, and the following properties are reported: Natural water content of the clay = 22.5% Specific gravity of the soil grains 2.72 Preconsolidation pressure 110.0 kN/m2 Compression index = 0.52 Swelling index 0.06 a. Is the clay normally consolidated or overconsolidated? b. If a 2 m high compacted fll with a unit weight of 20.0 kN/m3 is placed on the ground, what would be the final consolida- tion settlement? GL 2.0 m Sand 3.0 m Clay 3.0 m Bedrock FIGURE P2.13

Q#3: For a normally consolidated clay layer in the field, the following values are given. Thickness of clay layer = 2.6 m Compression index = 0.28 Average effective pressure on clay layer 127 KN/m² Secondary compression index = 0.02 Δσ’ = 46.5 KN/m² Void ratio = 0.8 Time of Primary settlement = 1.5 years What is the total consolidation of the clay layer five years after the primary consolidation settlement?

For a normally consolidated clay layer in the field, the following values are given:Thickness of clay layer = 8.5 ftVoid ratio ?? = 0.8Compression index ?? = 0.28Average effective pressure on the clay layer ??′ = 2650 lb ft2 ⁄∆?′ = 970 lb ft2 ⁄Secondary compression index ?? = 0.02What is the total consolidation settlement of the clay layer five years after the completionof primary consolidation settlement? (Note: Time for completion of primary settlement= 1.5 years.)

If a representative clay specimen 20 mm thick, under double drainage, took 121 minutes for 90% primary compression, estimate the time in days required for 50% primary compression of a field layer 2 m thick, bounded by impervious boundary at the bottom and sand at the top. a.679 b.781 c.650 d.725