FINITE CAVITY EXPANSION IN DILATANT SOILS - LOADING ANALYSIS

An analysis of the quasi-static expansion of a cylindrical or spherical cavity in an infinite dilatant elastic-plastic soil is presented. Closed form solutions for the stress and displacement fields in the soil during the expansion of the cavity are given. The soil is modelled as linear elastic-perfectly plastic, using a non-associated Mohr-Coulomb yield criterion. An explicit solution for the pressure-expansion relationship is obtained with no restriction on the magnitude of the deformation. It is found, in particular, that the radius of the cavity increases indefinitely as the cavity pressure approaches a finite limiting value. This limiting pressure can be determined analytically with the help of a single expansion of an infinite series. The novelty of the new solution lies in the introduction of dilation to the analysis of large strain expansion. Examples of the implications of the new analysis in geotechnical engineering are discussed.