Simulation of Rock Breaking Based on FEM-CZM Method and Its Application in Disc Cutter Parameter Optimization

Abstract

TBMs rely on the cutters to directly cut into the rock surface for excavation. The design of the disc cutter parameters can significantly affect the TBM's tunneling performance. In this study, a three-dimensional numerical model of a TBM disc cutter cutting Chongqing sandstone is established by the FEM-CZM coupling method, and verified with laboratory tests. The mechanical characteristics of rock breaking using a disc cutter and rock crack propagation laws were investigated. An orthogonal test was designed to analyze cutter parameter optimization under multiple factors (blade width, blade angle, penetration, and cutting speed). The results show that the force of cutter during the cutting process increases as the blade width and angle increase. Cracks that extend laterally in the rock are more sensitive to the blade angle, and the choice of blade angle needs to be taken into account when designing the cutter spacing. The degree of influence of each factor on rock-breaking efficiency is as follows: penetration > cutting speed > blade angle > blade width. The design of the cutter parameters should give priority to determining the optimum penetration depth, other parameters can be changed to meet the energy consumption and wear requirements of different engineering geologies.