How do you calculate consolidation settlement of foundations on clay?

Consolidation settlement S = Cc*H/(1+e0)*log((sigma'0 + delta_sigma)/sigma'0) for normally consolidated clay, where Cc = compression index, H = layer thickness, e0 = initial void ratio, sigma'0 = initial effective stress, delta_sigma = stress increase. For overconsolidated clay, use recompression index Cr until reaching preconsolidation pressure. Time for settlement: T = Cv*t/H^2 where Cv = coefficient of consolidation. Double drainage halves consolidation time. Settlement continues for years in thick clay layers.