基于离散元的超声波振动辅助TBM滚刀碎岩分析

Discrete element‑based rock breaking analysis of the ultrasonic vibration‑assisted TBM disc cutter

超声振动辅助碎岩技术以其弱化岩石强度、降低切削力、加快钻进速度等优势受到广泛关注,将超声振动技术与滚刀结合,能有效提升隧道硬岩施工滚刀破岩效率。采用颗粒流离散元软件对超声波振动辅助滚刀碎岩过程进行了模拟研究,结果表明,超声波振动能够产生周期性应力波并向岩石内部传播,在岩石的近表面区域出现较强的拉应力,有助于浅层岩石的张拉破坏。超声波振动提升了岩石内部裂纹的生成规模,加快了裂纹的生成速度,提前了裂纹初次萌生时间,对滚刀的破岩性能有良好的增益效果。超声波振动下岩石裂纹生成更加平稳,减少了跃进式破碎现象,能够避免因剧烈振动产生的冲击载荷对滚刀产生异常磨损和破坏,对延长滚刀寿命具有促进作用。

Ultrasonic vibration⁃assisted technology is widely concerned for its advantages of weakening rock strength,reducing cutting force and accelerating drilling speed.The combination of ultrasonic vibration technology and the disc cutter can effectively improve the construction efficiency in hard rock in tunneling.The process of rock breaking by the disc cutter assisted by ultrasonic vibration is simulated with the particle flow discrete element software.The results show that ultrasonic vibration can produce a periodic stress wave and propagate into rock with strong tensile stress appearing in the near surface area of rock,which is conducive to the tensile failure of shallow rock.Ultrasonic vibration can enhance the crack formation scale inside rock,accelerate the crack formation speed,and advance the crack initiation time,amplifying the rock breaking performance of the disc cutter.With ultrasonic vibration,cracks grow more stable in rock,which reduces the phenomenon of leap⁃forward crushing,and can avoid the abnormal wear and damage of the disc cutter caused by the impact load caused by the violent vibration,which can help extend the life of the disc cutter.