2种切削顺序下TBM刀具破岩机理的数值研究

为研究切削顺序对全断面岩石掘进机(TBM)刀具破岩机理的影响,基于二维离散单元法,利用离散元仿真软件建立无围压条件下2把TBM刀具同时、顺次切削节理不发育岩石的仿真模型.在此基础上设计1组数值试验,模拟TBM刀具在不同刀间距下分别以这2种方式切割岩石时,岩石裂纹生成、扩展和岩石破碎块形成的全过程.最后,利用滚刀回转实验台对顺次加载方式下岩石的破碎模式进行验证.研究结果表明:切削顺序决定了岩石的破碎模式,但并不影响最优刀间距；当刀间距大于80mm时,顺次加载方式的破岩效率不再高于同时加载方式下的破岩效率；在2种加载方式下,岩石应力场的分布基本对称；破碎块的形成与侧向裂纹的交汇密切相关.

Numerical study on mode of breaking rock by TBM cutter in two cutting orders

In order to research the effect of cutting orders on breaking mechanism of tunnel boring machine(TBM) cutter,based on the two-dimensional discrete element method,simulation models of breaking rock without joints by two TBM cutters in simultaneous and sequential orders under confining pressure-free were established using discrete element simulation software.A series of numerical experiments were designed and the whole process of production and propagation of crack and rock breaking were simulated in the conditions.Finally,an experiment was carried out on the rotatory cutting machine.The simulation results show that the cutter order determines the breaking mode,but the optimum cutter spacing is not affected.When the cutter spacing is larger than 80 mm,the efficiency of breaking rock in the sequential order is no longer higher than that in the simultaneous order.The distribution of the principal stress contour is almost symmetrical in two cutting orders.The formation of rock chip is directly bound up with the lateral cracks under the cutters propagation to each other and coalesce.