预制裂纹岩石压剪试验的数值模拟分析

采用岩石破裂过程分析软件RFPA^2D对预制裂隙大理岩试样的压剪试验进行数值模拟。数值分析表明，次生裂纹基本沿裂纹尖端萌生和扩展，所形成翼裂一股逐步趋向与荷载方向一致，这和试验结果是相吻合的。尽管某些数值分析结果和试验结果并不完全符合，但数值分析的模型和参数基本上有效地模拟了真实岩体介质的不均质性等力学特性。同时，采用该软件分析了加工小孔对裂尖应力状况的影响，加工小孔的存在对试验结果有一定影响，但并没有实质性影响。其影响主要在两方面：一是使翼裂起裂角变大，扩展路径变曲折；二是使材料更易于在裂尖引发二次(剪切)裂纹。最后，对锯齿形裂纹模型进行了初步的数值模拟。

NUMERICAL SIMULATION OF THE EXPERIMENT ON ROCK WITH PREEXISTED CRACKS UNDER COMPRESSION AND SHEARING

A numerical simulation of the experiment on rock with preexisted cracks under compression is presented by using a rock failure process analysis code,RFPA2D. It is shown that most of the wing cracks initiate from the tips of preexisted cracks and eventually align themselves with the load direction. This result is of good agreement with the previous experiment. Though some numerical results do not agree with the experimental data completely,the heterogeneity of real rock material is simulated effectively with the models and parameters. By analyzing the stress field near the tips of cracks,it is shown that there is no essential influence of processing small holes on the failure mechanism of rock,although the small holes make the initiation angles of wing cracks become large and facilitate the initiation of secondary shear cracks. Lastly,a preliminary numerical analysis is made on the zigzag cracks.