盘形滚刀破岩过程的数值研究

为了研究全断面岩石掘进机盘形滚刀的破岩过程以及盘形滚刀的结构参数（刀刃宽、刀刃角）对滚刀破岩特性的影响，利用离散元方法建立岩石与盘形滚刀的二维数值模型，研究了滚刀侵入岩石过程中贯入度、切削力以及裂纹数三者的关系，在此基础上通过仿真得到滚刀结构参数与岩石破碎特性的规律。研究结果表明：裂纹的扩展与滚刀受到的切削力密切相关；破岩过程中切削力先增大后减小的循环模式，证实了岩石跃进破碎特性。在盘形滚刀作用下，岩石中的应力是向下、向四周无限扩展的对称的应力泡。滚刀刀刃作用区域，应力值最高，随着滚刀贯入度增加，最大应力减小；远离滚刀刀刃区域，应力呈应力泡形式逐层降低至0。选择滚刀刀刃宽在10～15 mm之间，既避免滚刀受到的推力过大，又能提高滚刀的破岩效率；岩石破碎以滚刀刀刃下方向下发展裂纹的扩展为主，刀刃角在10°～20°之间，既能减少滚刀的磨损又能提高破岩效率。

Numerical research on rock fragmentation process by disc cutter

To study the rock fragmentation properties by the shield disc cutters and how the disc cutter structure parameters (the blade width and the blade angle of the disc cutter) influence the rock fragmentation properties by the disc cutters, numerical simulation of the rock fragmentation by the disc cutter is developed. Based on discrete element method (DEM), a series of two-dimensional numerical modeling between the rock and the disc cutter are established. This study researches the relationship among penetration、the cutting force and the crack number in the process of the disc cutter intrusive the rock. And then the law between the disc cutters structure parameters and fracture characteristics of rock has been discovered by a simulation example. The results show that the extension of the crack in the rock is related to the forces of the disc cutter. The cutting forces in the rock-fragmentation increases at first and then decreases. The phenomenon above proves the rock's jump break property. It demonstrates that the additional stress in the rock is stress bubble which is downward. Meanwhile, the stress bubble disperses unlimitedly under the action of the disc cutter. Besides the stress bubble is symmetric. What’s more, in the blade working region, the additional stress reaches a maximum when it is close to the edge of the disc cutter. While the maximum additional stress decreases when the penetration of the disc cutter increases. When it is far away from the disc cutter edge, the additional stress in additional stress bubbles form decreases gradually in layers until the additional stress reaches 0 MPa.When the blade width of the disc cutter is chosen properly, which arranges from 10 mm to 15 mm it can not only avoid the thrust force being too large but also improve the efficiency of the disc cutter working in the rock fragmentation. The crack in the rock occurs under the blade of the disc cutter and the crack propagation is downward and it is axial mainly. When the angle of the blade is between 10° and 20°, it can not only reduce the wear of the disc cutter but also improve the efficiency of the disc cutter.