全断面隧道掘进机破岩机理离散元分析

Rock Failure Mechanism Analysis With Discrete Element Method by Using Tunnel Boring Machine

摘要:

将基于微观胶结试验得到的岩石微观力学模型植入离散元软件，模拟滚刀破岩过程并重点分析滚刀破岩各阶段的宏微观机理.结果表明：滚刀破岩过程按破岩阻力和侵入深度的关系可以分为3个阶段，即加载阶段、卸载阶段和残余跃进阶段；破岩过程中的胶结破坏主要分为拉破坏和剪扭破坏2种类型，其中，中裂纹主要由拉剪扭复合破坏引起，斜裂纹主要由拉破坏引起，证实了张拉破坏理论.加载阶段是滚刀破岩的必经阶段，卸载阶段是滚刀破岩的关键阶段，有效利用卸载阶段破碎特性可以提高破岩效率.

Abstract:

The process of rock cutting was simulated by discrete element method software where the reasonable contact model for rock summarized from the micro bond contact experiment was implanted. The macroscopic and microscopic mechanism on the crack propagation of each stage during rock cutting was investigated. The results show that: the process of rock cutting can be divided into three stages, i.e. loading stage, unloading stage and residual leaping broken stage; failures of the bonds mainly exhibit tensile failure and sheartorsion failure. The crack under the tip is mainly caused by sheartorsion failures while oblique crack is mainly caused by tensile failures. Therefore, the tension failure theory was confirmed. The unloading stage is the critical stage of the overall process and the efficiency of rock fragmentation will be improved if the fragmentation behavior of unloading stage is efficiently used.