Analytical solutions to expansion of cylindrical cavity in linear softening soil

Based on the results of conventional triaxial compression tests for a soil, a trilinear elasto-plastic model is proposed to simulate the stress-strain softening curve. According to this curve, the constitutive relation between the bulk strain and two principal strains is established. By using Mohr-Coulomb's yield criterion as the initial yield function with plastic flow phases stage and constructing the rational yield function for the strain softening phase stage, the analytical solutions to the stress, strain, and displacement fields for the expansion of cylindrical cavity are presented. Finally, a computational example is used to show the radii of different stress zones and the corresponding internal pressure.