A 20.0-mm-thick clay specimen (Gs = 2.70, w = 35.0%) is subjected to a doubly drained consolidation test. After a few increments, when the vertical stress on the specimen was increased from 120 to 240...

A 20.0-mm-thick clay specimen (Gs = 2.70, w = 35.0%) is subjected to a doubly drained consolidation test. After a few increments, when the vertical stress on the specimen was increased from 120 to 240 kN/m2 , the specimen thickness was plotted against time as shown in Fig. RE8.16. Determine the following during this stress increment.

a. Coefficient of consolidation b. Coefficient of volume compressibility c. Permeability (hydraulic conductivity) d. Coefficient of secondary compression e. Compression index of the clay assuming it is normally consolidated at this stress level The above sample was taken from 5 m below the ground level at a site for a proposed construction of a warehouse with a large footprint. The soil profile at the site consists of 3.0 m of sand (γm = 17.5 kN/m3 ; γsat = 19.0 kN/m3 ) at the top, underlain by 4.0 m of clay (Gs = 2.72, w = 35.0%). There is a gravel layer below the clay layer. Water table is at 2.0 m below the ground level. f. If the clay is normally consolidated, what would be the preconsolidation pressure of this specimen in the consolidation test? g. If the warehouse imposes a uniform stress of 25 kN/m2 at the ground level, what would be the final consolidation settlement? h. What would be the consolidation settlement in 1 year? i. What would be the pore water pressure at the middle of the clay layer after 1 year? j. Assuming that the consolidation at the site is almost complete after 10 years, estimate the secondary compression settlement during the next 15 years.