Change in Shear Strength of Saturated Soft Clay due to Swelling and Consolidation

Geotechnical properties of Ariake marine clay (V)

Abstract

Reduction in effective overburden pressure results in overconsolidation of clay. During unloading and reloading, overconsolidation ratio, OCR, has a pronounced effect on the undrained shear strength of clays.
If the OCR is constant, the ratio of the undrained shear strength to effective overburden pressure, s_un/p, for the overconsolidated clay is constant regardless of the preconsolidation pressure.
For values of OCR<10 in the case of unloading, the s_un/p can be expressed approximately by the a th power of OCR, in which a has a value of-0.2 to-0.4 in Ariake marine clay.
If loading is applied after a simple rebound, there exists a linear relationship between undrained shear strength and effective overburden pressure and the incremental ratio of the undrained shear strength to increment of consolidation pressure increases as values of OCR for clay of the same preconsolidation pressure.