考虑围压效应的块状节理岩体变形破坏数值模拟

节理岩体变形模量是深部岩体工程设计及稳定性分析的重要设计参数，开展围压对节理岩体变形特征及破坏形态的研究具有重要意义。采用离散元数值模拟与室内试验测试相结合的研究方法，开展不同围压条件下含两组预制节理的块状节理岩体三轴压缩变形破坏数值模拟研究，主要结论如下：（1）块状节理岩体的变形模量随着围压的增大而增大，当围压超过4 MPa时，变形模量的变化趋于平缓；（2）块状节理岩体的破坏模式分为两种：一是产生沿着已有节理面的滑动破坏；二是产生穿过整个岩体的剪切破坏，且随着围压的增大，块状节理岩体的破坏模式由节理滑动破坏向岩块剪切破坏转变；（3）对于1+2、2+3、3+5和5+7块状节理岩体模型，发生破坏模式转变的围压分别为0.5、1.0、4.0和4.0 MPa。

Numerical simulation on deformation and failure of blocky jointed rock mass considering the effect of confining pressure

The determination of deformation modulus of jointed rock mass is of great importance for the design and stability analysis of deep rock mass engineering. Therefore, it is of great engineering significance to study the effect of confining pressure on deformation characteristics and failure modes of jointed rock masses. Based on discrete element numerical simulations and laboratory testing data, triaxial numerical simulations on deformation and failure of blocky jointed rock masses with two pre-existing joints under different confining pressures were carried out. The main conclusions are as follows: (1) The deformation modulus of blocky jointed rock masses increases with the increase of confining pressure. When the confining pressure is more than 4 MPa, the change of deformation modulus tends to be gentle; (2) The failure modes of blocky jointed rock mass can be divided into two types: the sliding failure along the existing joints and the shear failure across the whole rock mass. With the increase of confining pressure, the failure mode of the blocky jointed rock mass model develops from sliding failure with joints to shear failure in intact rock; (3) For 1+2, 2+3, 3+5 and 5+7 blocky jointed rock mass models, the confining pressures at which the failure mode changes are 0.5, 1.0, 4.0 and 4.0 MPa, respectively.