The figure shows a soil profile where a clay layer will consolidate under an embankment loading of 150 kPa. There is no capillarity. Your firm performed two consolidation tests: i) one test indicated that the soil is over-consolidated, with σ’_p  = 110 kPa. ii) one test indicated that the soil is normally consolidated. Both tests gave the same C _rε and C _cε values. Assume C _cε = 0.25.

(a) Determine the initial σ’_v at the middle of the clay layer (i.e., at depth 5.5 m).

(b) Compute the settlement due to the embankment loading, assuming that the over-consolidated assumption is correct (σ’_p = 110 kPa).

(c) Compute the settlement again, this time assuming that the soil is normally consolidated.

Sand Ya = 16 kN/m3 Y = 18 kN/m3 2.5 Clay Y = 20.5 kN/m3 Cr. = 0.025 Co = 0.025 8.5 Depth (m),