裂隙岩体局部化破坏分析的多重势面分岔模型

采用多重势面弹塑性分岔理论对裂隙岩体的局部化破坏进行计算模拟．基于多重势面弹塑性理论分析局部化问题，构造了适用于裂隙岩体破坏的多重势面不连续分岔模型，并使用数值方法求解局部化方阶在有限元方法的基础上，使用该模型计算裂隙岩体的局部化破坏条带．算例分析表明这一模型用于分析裂隙岩体的局部化破坏是有效的．

MULTI-POTENTIAL DISCONTINUOUS BIFURCATION MODEL FOR LOCALIZATION OF JOINTED ROCKS

In the framework of multi-potential elasto-plastic theory, a discontinuous bifurcation model to analyze damage localization of jointed rocks is presented in this paper. Three potential functions are adopted to simulate the complicated nature of jointed rocks in this model. Classical localization analysis is performed with the tangent stiffness tensor, thus the condition for weak discontinuous bifurcation is derived. Due to the dependence of the localization tensor on the direction of localization bands, a numerical method is formulated to determine this direction by minimize determinant of the localization tensor. Afterwards, the analysis process is coded in FEM to simulate the localization of jointed rocks. Finally, failures of several specimens under tension or compression are studied by using this model. The obtained results demonstrate the potential application of this model. However, two problems still need to be resolved in this model. First, the potential functions used in this model are traditionally chosen as Rankine or Mohr-Coulomb criteria, but it remains unknown whether there are much better ones or maybe a universal one for jointed rocks. Second, classical localization analysis considers only weak discontinuous bands in solids, while actually, recent studies have shown that weak discontinuous bands in solids usually evolved into much narrower ones, strong discontinuous bands. The evolution from weak bands to strong bands as well as the condition for strong ones in jointed rocks is still under study.