Simulation of cracks propagation and fractal characteristics of composite rock strata with holes and fractures

RFPA2D was used to simulate the crack propagation, failure mode, and fractal characteristics of composite strata with prefabricated cracks and holes under the uniaxial compression test. The crack propagation process was analyzed when the crack inclination angle and rock inclination angle changed. And it was concluded that: when the rock inclination angle is 0° and the crack inclination angle changes, the cracks are classified into X-type cracks and Y-type cracks. When the crack inclination angle is 0° and the rock inclination angle changes, the failure modes of the model specimens are divided into the through-cut failure mode of soft rock and the failure mode along the soft rock. The variation law of fractal dimension of cracks in the composite rock stratum with holes calculated by Matlab is the same as that of the compressive strength of the model specimen, and the fitting between fractal dimension and compressive strength has a significant linear relationship.