Numerical Simulation on Damage and Failure of Brittle Rocks under Different Confining Pressures

Abstract

A numerical analysis has been conducted to evaluate the effect of confining pressure on the damage evolution and the fracture process of brittle rock materials by using the rock failure process analysis code (RFPA2D). A fractal dimension D associated with material damage and a damage variable ω are defined to describe the damage process of the specimen subjected to tensile or compressive load. We find that the spatial distribution of microfractures is fractal and has very good statistical self-similarity in the specimen under different confined conditions. The fractal dimension D increases progressively with loading. Meanwhile, the damage variable ω develops from 0 to 1, and the specimen failure is characterized by the critical damage variable ωc with 0.4⩽ωc⩽0.8. The initial damage is delayed by the confining pressure. The confining pressure plays an important role in the mode of rock failure in numerical simulations. The tensile microfractures dominate near the brittle splitting of the specimens under no...