围压作用下TBM双刃中心滚刀破岩特性研究

Study on Characteristics of Breaking Rock by Double Edge Central Disc Cutter Under Confining Pressure

为了研究不同围压作用下双刃中心滚刀破岩规律,运用颗粒离散元建立其破岩数值模型,分析不同围压与刀间距对双刃中心滚刀破岩过程中裂纹扩展、比能耗等规律的影响.研究结果表明:双刃中心滚刀侵入破岩时,围压增加会抑制裂纹沿岩体垂直方向扩展.刀间距不同,围压增加对双刃之间的裂纹扩展影响不同;岩石破碎存在三种破碎模式且刀间距适中时,围压增加会促进破碎模式转变;存在最优刀间距使比能耗最小且最优刀间距随围压增加而增加;实验观测不同围压下双刃中心滚刀破岩过程裂纹扩展、破碎模式转变规律与数值模拟结果具有很好的一致性.

In order to study the law of rock-breaking by double edge central disc cutter under different confining pressure,a numerical simulation model was established based on particle discrete element. The change laws of crack propagation and specific energy were analyzed. The results show that,as the double edge central disc cutter invades into the rock,the crack propagation along the vertical direction will be constrained with the increase of confining pressure. The influence of confining pressure on the crack propagation is different between the two cutter edge when the cutter spacing is different. There exists three kinds of breaking modes as the confining pressure and cutter spacing change. The increase of confining pressure will change the breaking mode when cutter spacing is moderate. There exists an optimal cutter spacing and the optimal cutter spacing tends to increase with the increase of confining pressure. The experimental results show that the double edge central disc cutter invaded into rock under different confining pressure is in good agreement with the simulation results in the effect of crack propagation and the change of breaking mode.