TBM刀盘与岩石相对刚度对盘形滚刀受力的影响分析

Influence Analysis of Relative Stiffness Between Cutter Head and Rock on Disc Cutters' Forces of TBM

TBM掘进过程中,滚刀与岩石之间产生相互作用力.针对滚刀与刀盘受力的均衡性,提出刀盘与岩石相对刚度的概念,用刀盘厚度与岩石弹性抗力系数之比表示相对刚度,并分析其对滚刀及刀盘均衡受力的影响.建立刀盘与岩石相互作用的三维弹性支点力学模型,运用有限元方法对其进行分析.计算表明,刀盘上各滚刀分担的推力并非均匀分布,而是具有一定的差异性.刀盘与岩石相对刚度越大,地层相对较软,各滚刀推力越接近于平均值,刀盘以整体轴向位移为主,弯曲变形很小.反之,地层较硬,各滚刀分配的推力差异较大,刀盘整体轴向位移小,但产生明显的相对弯曲变形.为使滚刀受力均衡,应根据地层的软硬程度设计刀盘刚度并合理使用掘进参数.

When TBM driving,the cutter head was pushed onto tunnel face and interactions between disc cutter and face rock was caused.In view of mechanical balance of disc cutters and cutter head,relative stiffness between the cutter head and the rock was proposed.It was defined as the ratio of the cutter head thickness to rock elastic resistance coefficient.Then relative stiffness was used to analyze mechanical balance of the disc cutters and the cutter head.On the base of elastic and point contact between disc cutters and rock,a 3D elastic links model for the interactions was created.Then the model was solved by finite element method to simulate the relative stiffness influence on thrust force of the disc cutters.The computation results indicate that thrust forces distributes of the disc cutters are not uniform,but uneven.The larger relative stiffness is and the softer the rock is,the more uniform the thrust forces of the cutters are.The cutter head mainly produces axial displacement,and its bending deflection is tiny.On the contrary,if the rock is hard,the cutters thrust forces will be very unevenly distributed.The cutter head axial displacement is tiny,but the cutter head bending deflection is obvious.The cutter head stiffness should be designed rationally by the rocks hardness to obtain the even thrust forces distributes of every disc cutters,the TBM＇s total thrust force and advance rate are also utilized rightly according to the rock hardness along the tunnel.