Study of contact pressure distribution between cutter and rock surface using the discrete element method

Abstract

The contact pressure distribution between the disc cutter and rock surface plays an important role in cutter force prediction, cutter optimization and performance prediction of the tunnel boring machines . The present study presents a preliminary investigation of the direct measurement of the contact pressure between cutter and rock surface using the Discrete Element Method . Firstly, to realistically reproduce the cutting process and to reduce the simulation time, various modelling set up methods are conducted and discussed to choose a proper method. Secondly, contact pressure distribution are fitted by different distribution functions. Gauss distribution and Lorentz distribution were found more suitable to describe the distribution. Thirdly, it is found that the maximum contact pressure is only related to rock properties and slightly affected by other factors like cutter speed or penetration depth. And the contact angle corresponding to maximum contact pressure can be easily calculated by Cutting Coefficient, which is the ratio of rolling force to normal force. The cutting process is also greatly influenced by the presence of discontinuities . The maximum contact pressure is reduced when bedding plane is inclined to the cutting direction, which indicates the best cutting performance. These findings can provide insights and improve the understanding of the fragmentation mechanism beneath the cutter and cutter force prediction in the field.