Exact drained solution for cylindrical cavity expansion in modified Cam Clay soil

This work presents a novel, exact solution for the drained expansion of a cylindrical cavity in modified Cam Clay soil. Following the rigorous definitions for the mean and deviator stresses and therefore an exact constitutive relationship, the problem is formulated as a set of first-order simultaneous differential equations in the plastic zone with the aid of an auxiliary variable. The solution procedure proposed has the advantage over the conventional similarity method in that it is directly applicable to the cavity expansion problem of finite initial radius. Also the solution derived is sufficiently general to be applied to a more realistic situation of non-isotropic in situ stress condition and to the cavity contraction problem. Extensive parametric studies have been carried out to illustrate the effect of the overconsolidation ratio on the cavity expansion and stress distributions around the cavity, as well as on the stress path and specific volume change due to expansion. The present solution can and is used here as a benchmark for numerical solutions of cavity expansion in modified Cam Clay soil using Abaqus, the finite-element analysis commercial program.