中文摘要：

为了研究盾构切刀作用下岩石的动态响应机制，从岩土细观角度出发，采用颗粒离散元法建立了岩石与切刀的二维数值模型，并对切刀破岩过程的影响因素进行分析。研究表明：切刀切削岩石的过程，是由数个小剪切和一个大剪切所组成的、不断循环的过程，它造成了切削力随着切削行程的不断波动；刀具尖端的破坏作用最为明显；切削力和裂纹数随着切削行程不断增大，裂纹的生成和扩展需要更大的切削力：从切削性能来看，正前角时岩屑更容易排出，切削效率更高；对切削力和裂纹数进行统计分析发现，切深比切削速度对破岩的影响更为显著。

英文摘要：

In order to study the dynamic response mechanism of the rock fragmentation and its influential factors, fi＇om meso-level structure of rock, a numerical model for the rock and shield machine cutters is proposed based on the particle flow code （PFC2D）. The results show that the rock fragmentation process is composed of the cycle of various-small shearings and one large shearing, which causes the cutting force to fluctuate continuously. As the cutter distance increases, the cutting force and rock cracks increase. It shows that the formation of the cracks needs greater forces. From the cutting performance aspect, the positive rake angle of the cutter produces higher cutting efficiency than the negative one. The cutting forces and crack numbers data are statistically analyzed, and the results show that the effect of the cutting depth is greater than the cutting speed.