岩石材料的非线性强度与破坏准则研究

将三维应力条件下岩石材料的非线性强度特性，分解为偏平面上的非线性与子午面上的非线性，在偏平面上研究中主应力效应，在子午面上研究静水压力效应，以及中主应力与静水压力的耦合效应。通过八面体面外法线方向与空间滑动面外法线方向二者之间的线性插值，提出统一强度理论的物理模型，每一种材料对应于一个特定的剪切破坏面，进而建立广义非线性强度理论，该理论具有明确的物理模型、清晰的物理概念，4个相互独立的材料参数均具有明确的物理意义，在主应力空间的强度面连续光滑。通过5种岩石材料的真三轴强度试验结果的验证表明，该理论可较好地描述不同类型岩石材料的非线性强度特性。基于广义非线性强度理论提出2种变换应力空间，将广义非线性强度理论分别变换为2个新空间中的Mohr-Coulomb准则和Drucker-Prager准则，通过5种岩石材料的真三轴强度试验结果的验证表明，该理论可以在变换应力空间中以Drucker-Prager准则、Mohr-Coulomb准则的形式应用。

RESEARCH ON NONLINEAR STRENGTH AND FAILURE CRITERION OF ROCK MATERIAL

The nonlinear strength characteristics of rock materials under 3D stress states are studied in the deviatoric plane and meridian plane. The effect of intermediate principal stress and hydrostatic pressure as well as coupling effect of them are studied in these two planes respectively. By conducting linear interpolating of external normal vectors of octahedral plane and spatial mobilized plane，a model of the unified strength theory is proposed. Each kind of material corresponding to a shear failure plane，then the unified strength criterion is established. The criterion has four parameters，all of which have obvious physic significance and it owns continuous smooth failure plane in the principal stress space. It is verified by triaxial compression test data of five different rocks that have been published. Two transformed stress spaces are proposed based on the unified strength criterion；then the criterion is transformed into Mohr-Coulomb criterion and Drucker-Prager criterion in the new stress space respectively. Triaxial compression test data show that the unified strength criterion can be used as Mohr-Coulomb criterion and Drucker-Prager criterion in transformed stress space.