节理岩体下TBM单刃和双刃滚刀破岩特性研究

摘要

In this study, we investigated the breaking behavior of rock penetrated by two types of tunnel boring ma⁃chine ( TBM) disc cutters with respect to the geological condition of the joint. We used the particle discrete element method to establish a model for penetrating the rock with the two types of cutters and analyzed the dynamic breaking behavior of rock and crack propagation. Our results show that the formation and propagation of cracks involves two classic stages and that the force and number of cracks differ when penetrating a jointed rock using two types of cut⁃ters. A change in the joint angle has guide and blocking effects on crack propagation. When using a double⁃pint cut⁃ter and the joint spacing is more than 80 mm, this angle controls the crack propagation. With respect to the forma⁃tion of rock chips, the rock exhibits regular and joint⁃coordinated breaking modes based on the type of slag pro⁃duced by the breaking rocks. When using a single⁃point cutter, a change in joint angle deflects the stress distribu⁃tion caused by the cutter inside the rock but has little effect on the stress distribution caused by the two⁃point cutter. The rock⁃breaking efficiency of the two cutters changes with changes in the joint characteristics. When the cutter spacing is adequate, the double⁃point cutter has higher efficiency than the single⁃point cutter. There is an optimal cutter spacing that maximizes the efficiency of breaking rocks when the double⁃point cutter is penetrating a jointed rock, and this spacing will increase first and then decrease with increases in the joint angle.%为了研究在考虑节理地质条件下的两种TBM滚刀破岩规律，采用颗粒离散元法建立不同节理特征下两种滚刀的侵入破岩模型，分析节理岩体下两种滚刀侵入破岩的动态过程、裂纹扩展等规律。研究表明：两种滚刀在侵入节理岩体时，裂纹形成和扩展分为两个典型阶段，两种滚刀在受力以及裂纹数目上存在差异；随节理特征的改变，节理对两种滚刀作用下的裂纹扩展呈引导和阻隔效应，节理间距超过80 mm后，双刃滚刀作用下的裂纹扩展依然受到节理的控制；依据两种滚刀破岩产生的岩碴方式分为常规破岩和节理面协同破岩两种形式；单刃滚刀作用下岩体内部的应力分布随节理倾角变化而偏转，双刃滚刀作用下的应力分布随节理倾角变化影响不大；两种滚刀破岩效率随节理特征改变而改变，当刀间距合适时，双刃滚刀相比单刃滚刀破岩效率要高；双刃滚刀侵入节理岩体存在一个最优刀间距使得破岩效率最高，最优刀间距随节理倾角增加先增大后减小。