土体应变局部化现象的理论解析

An analytical solution for criterion of onset of strain localization of soils

引起土体失稳的应变局部化现象是在特定应力状态下,土体本构产生的分叉特性。基于有限变形理论推导了应变局部化产生的三维解析解。基于应变局部化的理论解析,分析了轴对称和平面应变条件下应变局部化现象在弹塑性硬化阶段的存在性以及剪切带的方向性。 理论分析表明,在轴对称条件下,土体应变局部化产生于土体应力-应变的软化阶段,而平面应变条件下,土体应变局部化一般出现在应力-应变的硬化阶段,其剪切带方向角的理论预测与 Arthur 等[1]建议值较为一致。

Strain localization of soils as a stable behavior of soils can be understood as a bifurcation in the macroscopic constitutive properties in a special stress state. In this paper, a 3-D analytical solution for the criterion of onset of strain localization is deduced based on the finite deformation theory. The theoretical analysis shows that, onset of strain localization always occurs in the softening regime of constitutive response under axisymmetric conditions; and inception of strain localization generally occurs in the hardening regime under plane strain conditions, and shear bands’ orientation of theoretical prediction exhibits an agreement with that suggested by Arthur et al[1].