When a consolidation test is performed on some soils, the virgin compression region is not linear, but bilinear. Figure P8.37 shows such a compression curve from a 15 ft thick layer.

Required:

(a) What vertical strain, occurs when the soil is loaded from an initial  σ'v₁ = 560 psf to σ'v₂ = 3000 psf?

(b) If you load the soil further, to σ'v₃ = 4000 psf, how much additional settlement occurs?

(c) Finally, if you unload from 4000 psf back to σ'v₄ = 3000 psf, what additional deformation (in ft) occurs?

o, = 560 psf o, = 980 psf C = Cs = 0.032 Co = 0.14 Er ai2 = 3000 psf o3 = 4000 psf Cor = 0.17 log r'.