全断面隧道掘进机滚刀破岩尺寸效应离散元分析

Discrete Element Method Analysis of Rock Failure Mechanism Considering Scale Effects of Tunnel Boring Machine Cutter

摘要:

为了给室内模型试验或数值模拟试验提供直接的指导及实际工程间接的参考，将基于微观胶结试验得到的合理的岩石微观力学模型植入离散元软件，模拟了不同试样尺寸滚刀破岩过程并分析了各因素对滚刀破岩过程的影响.结果表明,不同试样尺寸滚刀破岩过程按破岩阻力和侵入深度的关系均可以分为3个阶段，即加载阶段、卸载阶段和残余跃进阶段；室内模型试验中，滚刀刃宽与岩石试样宽度的比值（相对比值）存在一个临界值，当试验中选取的相对比值小于该临界值时，可以减小试验过程中的边界效应.

Abstract:

In order to guide indoor model experiments or numerical simulation directly and engineering practice indirectly, the process of rock cutting was simulated by using the DEM software where the reasonable contact model for rock summarized from the micro bond contact experiment was implanted. The influence of cutter width and rock sample size on the rock fragmentation was investigated. The results show that cutter width is too small to keep the stability of the actual TBM construction. However, large cutter width in small sample size has a significant boundary effect which affects the test result. In the indoor model test, there exists a critical ratio of the cutter width and the rock sample width (relative ratio). If the relative ratio in the test is less than the critical ratio, the boundary effect can be reduced during the test.