TBM边缘滚刀破岩机理的数值研究

为研究刀刃角和不同被切削材料对全断面硬岩掘进机（TBM）边缘滚刀破岩机理的影响规律，基于二维离散单元法，利用UDEC仿真软件建立了一系列边缘滚刀破岩数值模型，对边缘滚刀作用下被切削体内部裂纹生成、扩展和破碎过程进行数值模拟。仿真结果表明：张拉破坏是滚刀破岩时裂纹生成与扩展的主要原因；对于不同刀刃角的边缘滚刀接近弧面下端的斜裂纹长度要比弧面上端的长；大理岩裂纹扩展能力和破岩效率均随刀刃角的增大先增大后减小，因此对于硬岩刀刃角不宜过小也不宜过大；随着被切削材料强度增大，裂纹扩展越不充分，裂纹扩展能力和破岩效率均降低；与其他材料相比，TBM边缘滚刀对大理岩破坏损伤范围最小，破岩效率最低。最后通过实验和工程数据验证了仿真方法的正确性和可行性。

Numerical simulation of rock-breaking mechanism by gage disc cutter of TBM

In order to study the impact by disc cutter’s blade angle and different materials to be cut on the rock breaking mechanism of the full face hard rock tunnel boring machine(TBM)，a series of interaction numerical models for rock-breaking with the gage disc cutter were established by UDEC.Based on the two-dimensional discrete element method，the process of the materials crack initiation，propagation and rock breaking due to the effect of the gage disc cutter were simulated.The results show that：(1)The tensile failure is the main reason for the crack initiation and propagation；(2)The length of cracks close to the upper end of cambered surface is longer than those which are close to the lower end；(3)Both of the crack expansion ability of marble and the breaking efficiency of disc cutter show an increasing trend at first and decreasing with the increasing of blade angle in the next part，so a proper blade angle should be chosen for hard rock；(4)Due to the increasing materials’ strength，the cracks show insufficient propagation，and the ability of crack expansion and the breaking efficiency of disc cutter are both decreased.In addition，compared with other materials，the gage disc cutter shows the smallest damage range for marble and the lowest breaking efficiency.Finally，the correctness and feasibility of the numerical method are verified by the experiment test and engineering data.