考虑多尺度结构的贯通节理岩体损伤摩擦耦合模型

Coupled damage and friction model for persistent fractured rocks considering multi-scale structures

基于贯通节理岩体结构的多尺度特征,采用两步均匀化方法,给出了节理岩体在复杂荷载作用下的自由焓表达式,建立了节理岩体损伤摩擦耦合本构模型。模型可同时考虑岩块损伤扩展、微裂纹滑移剪胀、法向刚度恢复,节理面多阶凸起体滑移磨损、剪胀演化以及节理与岩块相互作用等特征,较好地反映岩体内部微裂纹、节理等不同尺度微结构变化对其力学特性的影响。采用Lac du Bonnet花岗岩三轴压缩试验、花岗岩节理剪切试验以及不同节理倾角与不同围压下Martinsburg板岩三轴压缩强度试验等成果对模型进行了验证,模型预测值与实测值相当吻合,论证了模型的准确性。

A coupled damage and friction constitutive model for persistent jointed rocks based on a two-step homogenization technique is proposed considering the influences of anisotropic damage growth of intact rocks, mobilized dilatancy behavior of microcracks, recovery of normal stiffness due to normal closure of closed microcracks, mobilized degradation of multi-order asperities of joints, shear dilatancy of joints, and interaction between joints and rocks. The effects of multi-scale structures （i.e., joint and microcracks） on the deformation characteristics of fractured rocks are better addressed by the proposed model. The existing laboratory triaxial compression tests on crystalline rocks, shear tests on joint specimens, together with triaxial compressive strength tests on Martinsburg slate under different confining pressures and joint configurations, are used to validate the proposed model. The good agreements between the model predictions and the test results demonstrate the accuracy of the proposed model.