Abstract

Full-face TBM (Tunnel Boring Machine) has been widely used in tunnel construction. Disc cutter is the main tool for TBM to break rocks, and its wear problem has become more and more obtrusive with the popularization of TBMs. Based on Discrete Element Method (DEM), a two dimension model is built with Particle Flow Code (PFC) to simulate the interaction between cutter and rock. A modified contact model was raised by adding parameters about plasticity and changing force-displacement law of one of the built-in contact model, providing a better way to simulate metals in PFC. The deficiency has been overcome that always regarding disc cutter as rigid body in former simulations. Based on the real size of cutter, full particle cutter-rock model was built to study cutter chipping under different intruding velocity and confining stress. In terms of the severity and continuance development potential, chipping was divided into three patterns. The results show that with the increase of intruding velocity, the chipping ratio shows an obvious linear ascendant trend, while confining stress has a diminutive influence for cutter chipping. The essential elements for chipping include a relative high intruding speed, a big enough penetration, and a hard rock granule in front of the cutter.

1. Introduction

With the acceleration of the construction of urban subways and water conveyance tunnels, TBM has been more and more widely used for its unique advantages. However, the frequent replacement of cutters caused by cutter wear has greatly affected the construction efficiency of TBM projects. So the research on cutter and cutter head is always one of the most important issues.

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