TBM滚刀破岩机理与影响因素数值模拟研究

为研究全断面岩石掘进机(TBM)滚刀破岩机理与破岩效果影响因素,采用颗粒流程序(PFC)建立滚刀破岩模型,通过单轴压缩与巴西劈裂试验结果,标定PFC程序参数,模拟滚刀破岩过程并对岩石强度、围压等破岩效果影响进行研究分析。结果表明:滚刀破岩历经前期压密、中期挤压剪切、后期挤压张拉破坏的组合破岩模式,整个破岩过程中滚刀出现反复加-卸荷交替及跃进破岩现象。岩石强度过高难以产生径向裂纹、强度过低侧向裂纹扩展不明显,破岩效果均不佳,TBM滚刀只对于中等强度范围内岩石较为合适。围压影响裂纹生成与扩展,较高时将抑制径向裂纹发育,降低破岩整体效果。研究成果可为TBM选型及滚刀设计提供一定参考。

Numerical Simulation Research on Rock Breakage Mechanism and Influence TBM Cutters

In order to study the rock breakage mechanism and influence of the full-face Tunnel Boring Ma-chine (TBM) cutters, the rock breakage model of cutter was established by the Particle Flow Code(PFC). Parameters of the PFC program were calibrated by uniaxial compression and Brazilian test. The rock break-age mechanism and the influence of rock strength and confining pressure on rock fragmentation by TBM cut-ters are successfully studied by using numerical simulation. The results show a composite rock breaking model of the rock breaking mechanism by TBM cutters through a process of the pre-compaction,the medi-um-time extrusion shear failure and the late extrusion tension failure. Loading and unloading alternately oc-curs throughout the process of the cutter. At the same time, the cutter shows the phenomenon of jumping. It is difficult for high rock strength to produce radial cracks, and there is no obvious lateral crack expan-sion with low rock strength. In both cases,the effect of rock breaking of TBM cutters is not obvious,only for a certain strength range of rock is more appropriate. The confining pressure affects the formation and ex-pansion of the crack, the higher confining pressure will inhibit the radial crack development to reduce the rock breaking effect. The research results can provide some reference for TBM selection and cutter design.