TBM刀具作用下节理岩石破碎模式研究

Breaking Modes of Jointed Rock under a TBM Cutter

为了研究节理岩石的破碎模式,文章建立了TBM刀具侵入节理岩石的2D离散单元模型,设计出两组0~15 MPa围压下切削仿真试验,其中一组用于双刀切割水平节理岩石,节理间距js取80 mm,100 mm,150 mm和200mm;另一组用于单刀切割倾斜节理岩石,节理倾角α为15°,30°,45°和60°。仿真结果表明,由于围压及节理对裂纹扩展的明显控制作用,切削过程中共观察到8种典型破碎模式。通过对破碎临界应力、标准切入率及裂纹扩展能力等指标进行定量分析发现,TBM刀具在有围压下的破岩效率较无围压的低,且随着节理间距的增加,破岩效率先增加后减少,而破岩效率随节理倾角的增加总体趋于增加。当节理间距为150 mm及节理角度为45°~60°时,切削效率相对较高。仿真获得的大部分破碎模式与文献试验观察到的宏观破碎现象具有良好的一致性。

In this paper, a 2D discrete element model was established for jointed rock to study its breaking modesunder a TBM cutter. Two groups of cutting simulation tests were designed under the confining pressure of 0~15MPa, one of which was taken for the horizontal jointed rocks under double cutters（joint spacing js： 80 mm, 100 mm,150 mm and 200 mm） and the other of which was taken for the inclined jointed rocks under a single cutter（joint an-gle α： 15°, 30°, 45° and 60°）. The results show that： 1） 8 typical breaking modes were observed during the cuttingdue to the obvious controlling effect of the confining pressure and joint on crack development; 2） the rock-breakingefficiency of a TBM cutter under confining pressure is poorer than that without confining pressure based on a quanti-tative analysis of the breaking critical stress, standard penetration rate and crack expansion capacity, and the rock-breaking efficiency of a TBM cutter first increases and then decreases with an increase of joint spacing, but increas-es on the whole with the increase of joint inclination; 3） the rock-breaking efficiency is relatively high in the case of150 mm joint spacing and a 45°~60° joint angle; 4） most rock breaking modes obtained by the simulation agree wellwith the ones given by the experimental observation in the literature.