考虑裂缝影响的页岩三轴压缩实验研究

为了探究页岩的破坏特征以及力学性质与裂缝之间的关系以及影响机理，本文采用RTR-1000岩石三轴力学测试系统对含不同裂缝（控制单一变量，使裂缝的条数、倾角、深度、填充物分别不同）页岩实施三轴实验，研究了不同裂缝形态下页岩的峰值应力、弹性模量以及破坏形式。实验结果表明：随着裂缝深度的增大，试件的弹性模量和峰值应力越小，同时破裂面与轴向应力的夹角变小；随着试件所含的的裂缝角度逐渐增大，页岩样品的弹性模量以及峰值压力的变化均表现凹型，并且随角度增大破裂面形态发生变化，当倾角为45° 时峰值应力和弹性模量降至最低；随着裂缝条数的增加，试件的弹性模量和峰值应力越小，其破坏形式为张拉和剪切破坏共存；随着裂缝充填物中方解石含量的增大，试件的弹性模量和峰值应力先减小再增大，当充填物中方解石含量为50 % 时值最小，并且岩样破坏主要是剪切破坏，随着方解石含量的增加，破裂面越容易经过填充带。

Experimental Study on the Three-axis Compression of Shale Considering the Influence of the Crack

In order to explore the influence of cracks on the mechanical properties and failure characteristics of shale, triaxial compression tests were carried out on shale with different crack depth, dip angle, number of cracks and fillers by using RTR-1000 rock triaxial mechanical testing system. The experimental results show that the fracture morphology affects the peak stress, elastic modulus and failure mode of shale. With the increase of crack depth, the elastic modulus and peak stress of specimens decrease, and the angle between fracture surface and axial stress decreases; with the increase of crack inclination, the elastic modulus and peak stress of specimens decrease first and then increase, and when the crack angle is 45 degrees, the value is the smallest, and the shape of fracture surface changes with the increase of crack angle. With the increase of the number of cracks, the elastic modulus and peak stress of specimens decrease, and the failure mode is the coexistence of tension and shear failure. With the increase of calcite content in crack filling, the elastic modulus and peak stress of specimens decrease first and then increase. When the content of calcite in filling is 50%, the value is the smallest, and the rock sample is broken. The failure is mainly shear failure. With the increase of calcite content, the fracture surface is easier to pass through the filling zone.