Analysis of Internal Stress Distribution and Mechanics Characteristics of Pre-existing Cavity in Brittle Rock Under Triaxial Cyclic Loading

Abstract

In order to reveal the internal stress distribution and failure characteristics of a pre-existing cylindrical cavity in granite under triaxial cyclic loading, bonded particle models containing a cavity were established to investigate the variation in crack propagation, stress distribution, number of micro-cracks, elastic modulus, and Poisson’s ratio with an increase in cavity diameter. The results show that the cavity diameter has a significant effect on the tensile cracks, compression-shear failure zone, and compressive stress distribution. The peak strength decreases as the diameter of the cavity increases. However, the number of cracks increases and the plastic deformation increases more obviously. With the increase of the cyclic axial stress, the decrease rate of the elastic modulus shows the rule of “first slow, fast later,” and the Poisson’s ratio increases. The distribution of local stress of σ1,σ2, andσ3 explains the behavior of the cracks around the cylindrical cavity well.