基于三维颗粒流模型的TBM滚刀顺次破岩的研究

摘要

从岩石细观破坏角度出发,基于颗粒离散元法,建立隧道掘进机(TBM)单滚刀破岩三维颗粒流模型,对比分析滚刀侵压破岩、滚压破岩模式下岩石裂缝的扩展规律和滚刀受力特征.在此基础上,建立双滚刀顺次破岩三维颗粒流模型,分析不同断面形态下岩石裂缝扩展的范围以及不同刀间距下破岩比能与贯入度的关系.结果表明:滚刀侵压破岩时,岩石以剪切破坏为主,垂直力随着贯入度的增加而增加,且贯入度为6mm时,垂直力达到58.0kN;滚刀滚压破岩时,岩石以张拉破坏为主,滚动力、垂直力呈锯齿状波动变化,平均滚压力约为5.6kN,平均垂直力为20.67 kN,小于侵压破岩时的垂直力;采用双滚刀顺次破岩时,与侵压破岩相比,滚压破岩的岩石裂缝纵向扩展深度较小、径向扩展范围较大,而且当刀间距与贯入度的比值较大时,滚压—侵压断面上的岩石裂缝最不易贯通,在两滚刀中间位置处容易形成岩脊;当刀间距与贯入度的比值为10时,滚刀破岩的比能最小,破岩效率最高.%In order to analyze the rock crack propagation and the stress characteristics of disc cutter under rock crushing and invading modes,the three-dimensional particle flow model for the single disc cutter rockbreaking of tunnel boring machine (TBM) was deduced from rock micro damage form on the basis of particle discrete element method.Then,under different cross section shapes,the range of rock crack propagation and the relationship between the rock breaking specific energy consumption and penetration under different disc cutter distances were analyzed through the three-dimensional particle flow model of double disc cutters sequentially rock-breaking.Results show.:when disc cutters invade and break the rock,the rock is given priority to shear failure.The vertical force increases with the penetration,and the vertical force is 58.0 kN when the penetration increases to 6 mm.When disc cutters roll and break rock,the rock is given priority to tensile failure.The rolling and vertical forces fluctuate like the zigzag.The average rolling force is about 5.6 kN and the average vertical force is about 20.67 kN,which is less than the vertical force of invasion crushed rock.When double disc cutters break rock sequentially,the longitudinal crack propagation depth of rolling rock-breaking is smaller and the radial crack extension scope is larger compared with the invasion of rock-breaking.When the ratio of disc cutter distance and penetration is larger,the rock crack of rolling-invasion section is the most difficult to transfix,and rock ledge is easily formed at the middle of two cutters.The specific energy consumption reaches the minimum when the ratio of disc cutter distance and penetration is 10 and the efficiency of rock-breaking is the highest.