THEORETICAL ANALYSIS OF EXPANSION OF CYLINDRICAL CAVITY BASED ON THE EXTENDED SMP CRITERION

摘要

In order to incorporate the strain-softening and shear dilatation behavior of geomaterials in the analysis, a strain-softening stress-strain model with stress-dropping and a simplified model of ε_v - ε_l and ε_3 - ε_1 are adopted.rnBased on the extended spatial mobilization plane (SMP) theory and the governing equations of axial symmetry in the plane strain condition, the partial differential equations for the boundary-value problem of cavity expansion in cohesive soil are established and the closed-form solutions of stresses, strains, displacements in the elastic and plastic regions are obtained. Consequently, the maximum radius of plastic boundary and ultimate cavity pressure are solved for cylindrical cavity expansion in finite mass. Based on numerical results, the strain-softening rate and the effects of soil dilatancy on expansion of cylindrical cavity are examined. Also comparative studies are made for the present solution and current solution based on Mohr-Coulomb criterion in order to explain the effect of mediated principal stress. The result indicates that the effects of the strain-softening, the shear dilatation and the intermediate stress are obvious.