Analysis of undrained cavity expansion in elasto-plastic soils with non-linear elasticity

A large strain analysis of undrained expansion of a spherical/cylindrical cavity in a soil modelled as non-linear elastic modified Cam clay material is presented. The stress-strain response of the soil is assumed to obey non-linear elasticity until yielding. A power-law characteristic or a hyperbolic stress-strain curve is used to describe the gradual reduction of soil stiffness with shear strain. It is assumed that, after yielding, the elasto-plastic behaviour of the soil can be described by the modified Cam clay model. Based on a closed form stress-strain response in undrained condition, a numerical solution is obtained with the aid of simple numerical integration technique. The results show that the stresses and the pore pressure in the soil around an expanded cavity are significantly affected by the non-linear elasticity, especially if the soil is overconsolidated. The difference between large strain and small strain solutions in the elastic zone is not significant. The stresses and the pore pressure at the cavity wall can be expressed as an approximate closed-form solution. Copyright (C) 2001 John Wiley Sons, Ltd.