Research on the Influence of Joint Dip on the Fracture Mechanics of Irregular Sandstone

In order to study the influence of joint dip angle on the mechanical mechanism of macro-micro fracture of 3 D irregular sandstone, the uniaxial compression simulation of jointed sandstone with different dip angles was carried out by RFPA^3D, and the influence of joint distribution and meso-heterogeneity on the mechanical behavior, fracture mode and energy evolution of sandstone was revealed. The results show that: the joint dip angle has a significant effect on the mechanical properties of sandstone, the uniaxial compressive strength and elastic modulus show obvious anisotropy under the influence of joint dip angle, and the force-displacement curve of the sample with dip angle α=0°~60° appears plastic platform section or approximate platform section. The load-step curve has a high correlation with the acoustic emission-step curve, and the more complex the failure mode is, the cumulative AE count is more larger. The meso heterogeneity of sandstone determines the crack propagation path of the specimen, and the failure mode varies greatly with the joint dip angle. The 45° specimen is mixed tensile shear failure, and the rest specimens are tensile failure. This study will be helpful in guiding the exploration and mining of sandstone mines in the study area.