Experimental study and numerical simulation of propagation and coalescence processes of pre-existing flaws in a transparent rock-like material

Abstract

Flaws in the rock play an important role in the failure of rock engineering. In this article, some rock-like specimens prepared by transparent resin material were used to investigate the propagation and coalescence processes of pre-existing closed three-dimensional flaws, and a series of uniaxial compressive tests were carried out to study the effects of flaw dip, flaw area, flaw friction coefficient, and composite flaw spacing on mechanical properties and flaw propagation and coalescence processes. Based on the particle flow method, the experimental results were verified by numerical simulation. The results show that there is a good agreement on flaw propagation rule revealed by the experiments and numerical simulations. In the case of the specimens with single-flaw, with the increase of the inclination angle, the peak stress of the specimen first decreases and then increases, when the inclination angle is 45°, the peak stress is the smallest. Meanwhile, the peak stress decreases with the increase of flaw area but increases with the increase of flaw friction coefficient. The spacing of the composite flaw has a significant influence on the strength, and the impact on the elastic modulus is not obvious. The results can provide a reference for the mechanism of flaw propagation and coalescence.