Triaxial test of coal-rock under effective confining pressure

Based on the coal samples from a layer of a block in Xinjiang, the coal-rock triaxial stress test was carried out in 15 groups, and the fracture mechanism and physical properties of coal-rock under low confining pressure, medium confining pressure and high confining pressure were determined. The test shows that under low confining pressure, the elastic modulus of the coal-rock is slowly rising as it is compacted. Under the medium confining pressure, the coal-rock has completed the compaction and turned into an elastic medium, and the elastic modulus has a linear increase trend. Under high confining pressure, the elasticity of coal-rock is destroyed and the resulting elastic modulus will Go linearly to change trends. And the larger the confining pressure interval value, the greater the cohesive force and the smaller the friction angle.