ANALYSIS OF CYLINDRICAL CAVITY EXPANSION IN FRICTIONAL COHESIVE SOIL BASED ON NON-BRITTLE SOFTENING MODEL

摘要

Damage parameter, taken as degradation grads of material mechanics capacity, is introduced to depict the soils softening behavior after yielding. Stress-dilatancy equation obtained by combination of Rowe's dilatancy equation and cohesion degradation expression is used to not only express soil dilation as a function of both friction and cohesion, but also describe trends from structure degradation. Based on the extended spatial mobilization plane (SMP) theory, the governing equations of axisymmetric problem in the plane strain condition and the partial differential equations for the boundary-value problem of cavity expansion in frictional cohesive soils are established. According to numerical results, the curves of pressure-expansion, stress response and plastic flow parameter in plastic zone for various damage parameters and different cohesions are investigated, from which the influence of damage parameter, cohesion and intermediated principal stress is observed. The method can provide theoretical basis for interpretation of some in-situ tests.