基于应变非线性软化的圆形硐室围岩弹塑性分析

ELASTO-PLASTIC ANALYSIS ON SURROUNDING ROCK OF CIRCULAR CHAMBER BASED ON STRAIN NONLINEAR SOFTENING

依据塑性力学全量理论,将岩体单轴压缩的非线性软化本构关系推广,得到复杂应力状态下圆形硐室围岩塑性区的等效应力与等效应变关系;籍以求得应变非线性软化的圆形硐室围岩塑性区半径、弹塑性区应力、应变和位移;进而求得相应情况下的硐室围岩平衡方程、地应力与硐室周边位移关系以及围岩压力方程。首次给出围岩弹性区承载力、塑性区承载力的表达式。

According to the entire theory of plastic mechanics, the relationship between equivalent stress and equivalent strain of circular chamber plastic zone in the complex stress state is deduced from nonlinear softening constitutive relation of rock under uniaxial compression. On this basis, the stress, strain, and displacements of elastic and plastic zone in surrounding rocks of chamber, are derived. Then the equilibrium equation of surrounding rocks, relationship between geostress and chamber displacement, and pressure equation of surrounding rocks, are obtained under corresponding conditions. The concrete formulation of carrying power of elastic zone and carrying power of plastic zone are first proposed. Because the assumed constitutive relationship agrees well with practical condition of rocks, the obtained results maybe more closely approach to corresponding actual values in surrounding rocks of chamber, compared with Fenna's solution that is based on ideal elasto-plastic relationship.