不同岩性下TBM滚刀破岩过程离散元分析

为了研究全断面岩石掘进机(TBM)的滚刀在不同岩性下的破岩机理,将考虑胶结尺寸的微观接触模型植入离散元软件,模拟了4种岩性下不同滚刀刃数的破岩过程,探究岩性、滚刀刃数对破岩效率的影响。模拟结果表明:不同滚刀刃数下的破岩过程可以分为3个阶段,即加载阶段、卸载阶段及残余跃进阶段;胶结破坏类型主要呈拉剪破坏与压剪破坏两种;滚刀破岩过程中受到的阻力可以用峰值法向推力表示,阻力大小取决于岩性,破岩阻力随着岩石单轴抗压强度的增大而增大;通过胶结破岩比能耗来评价破岩效率,对于坚硬岩,三滚刀破岩效率最高,对于强度较低的岩石,采用单滚刀破岩效率更高。

Discrete element method analysis on rock breaking process induced by TBM cutters under different lithologies

In order to investigate the rock failure mechanism using the TBM disc cutters under different lithologies, the micro contact model considering bond size was implanted into the discrete element software, which to simulate the rock breaking process with different cutter points under four lithologies. The influences of the cutter points and different lithologies on the effect of rock breaking efficiency were investigated. The simulation results showed that the rock failure process under different cutter points can be divided into three stages: loading stage, unloading stage and residual leaping stage. Bond failure mode can be divided into two modes: tensile shearing failure mode and compressive shearing failure mode. The mean resistance of the cutters on rock failure process can be expressed by the peak normal force. It depends on the lithologies and increases with the increasing of the rock compressive strength. The rock breaking efficiency is evaluated by the bond breaking specific energy. For hard rock mass, the three-point cutters have the highest rock breaking efficiency, and it is more efficient to use single-point cutter for lower strength rock mass.