THE GRADIENT PLASTIC SOLUTION OF ROCK DEFORMATION LOCALIZATION IN NIAXIAL COMPRESSION
岩石单轴压缩作用下变形局部化的梯度塑性解

The phenomenon of strain localization can be observed in many classes of engineering materials. Based on strain gradient plasticity theory, the second gradient term is introduced into the yield function. A constitutive model that describing deformation and failure of rock is proposed and it considers the strain gradient effect.The problem of localization of deformation under the condition of uniaxial compression is investigated. For one-dimensional problem, the constitutive relation of rock is bi-linear strain softening. The width of strain localization is dependent on internal length parameter. For two-dimensional problem, the same constitutive relation is used and the width of localized deformation is dependent on internal length parameter, elastic modulus and the descending modulus. The present analytical solution lays a theoretical foundation for determining internal length parameter in experiments.