TBM破岩机理的三维FEM-SPH耦合算法

采用改进的有限元-光滑粒子流体动力学耦合（FEM-SPH）的方法，建立了TBM单滚刀和双滚刀破岩的三维数值耦合模型，研究了TBM破岩机理，研究结果表明，压碎区形成阶段，在单滚刀推力的作用下，微裂纹向下扩展形成扇形破坏区；在切向力的作用下，微裂纹向前扩展形成另一个扇形破坏区，两个扇形破坏区组成了锥形破坏区；在微裂纹形成阶段，侧向裂纹的扩展速度大于中央裂纹的扩展速度；在微裂纹扩展阶段，中央裂纹的扩展速度大于侧向裂纹的扩展速度；当滚刀向岩体的边缘滚动时，边缘部位的岩石以扇形失效；压碎区形成阶段，每个滚刀单独作用在岩石上，在每滚刀的下方形成一个锥形破坏区；在微裂纹形成阶段，由于滚刀之间的相互作用，赫兹裂纹改变扩展方向；在微裂纹扩展阶段，赫兹裂纹连接和贯通，形成岩片。

Mechanism of rock fragmentation by TBM cutters using 3D FEM-SPH coupling method

FME-SPH coupling method was applied to simulate the mechanism of rock fragmentation by TBM cutters.The 3D coupling models of rock fragmentation by single TBM cutter and two TBM cutters were established.The mechanism of rock fragmentation by TBM cutters was analyzed.The conclusions are summarized as follows:for the rock fragmentation by single TBM cutter，in the stage of the formation of the crused zone，beneath the thrust of a single cutter，microcracks extend downward to form a fan-shaped failure zone；beneath the tangential force of a single cutter，microcracks propagate forward to form the other fan-shaped failure zone.The two fan-shaped failure zones consist of a conical failure zone in rock.In the stage of the formation of microcracks，the growth rate of radial crack is faster than that of median crack.In the stage of the propagation of microcracks，the growth rate of median crack is faster than that of radial crack.When the cutter scrolls to the edge of rock，the fan-shaped failure occurs on the edge of rock.for the rock fragmentation by two TBM cutters，in the initial stage，each cutter independently acts on the rock.A conical failure zone is first formed beneath each cutter.In the stage of the formation of microcracks，the propagation direction of the Hertzian cracks between two cutters are changed because of the interaction of two cutters.In the stage of the propagation of microcracks，Hertzian cracks between the two cutters coalesce，then the rock chipping is formed.