Measurement of fracture toughness using the distinct element method

Abstract

The rock and soil cutting efficiency and reliability of cutting tools are critical factors to tunneling. However, due to its complexity, in-depth researches on some problems existing in rock fragmentation has not been conducted. This paper introduces the mechanism of cutting rock and soil by cutting tools. On the basis of this mechanism, it establishes finite element models using ABAQUS software to simulate the cutting processes when a cutter and disc cutter are cutting rock and soil masses. The results show that when the cutting force of a cutter is stronger than the shear strength of soil mass, breakage occurs at the interface between the cutting edge and the soil mass, leading to a successful cutting. When a disc cutter is pressed into a rock mass, with penetration depth increasing, the maximum Mises stress of the rock increases almost linearly, and plastic strain accumulates constantly, resulting in the stress growing as well. The plastic deformation zone in the rock mass is larger than the area compressed by the disc cutter. Along the working direction of the disc cutter, the rock mass is subject to continuous compression, producing plastic deformation until a fragment is broken off from its parent body. In this paper, a finite element model is established to simulate the process of cutting rock and soil by cutting tools, and a method for analyzing the interactions between cutting tools and the rock and soil is provided.