裂隙岩体细观裂纹演化机制及局部力学特性研究

Study on meso-crack evolution mechanism and local mechanical properties of fractured rock mass

为研究含裂隙砂岩局部细观力学特性及不同倾角下岩体内部裂纹发育特征,通过单轴压缩试验及PFC^(2D)程序对不同角度单裂隙红砂岩进行细观裂纹演化模拟及裂隙周边应力监测分析,结果表明,单一裂隙的存在会显著影响完整试样的宏观破坏模式;在一定角度范围内,初始裂纹萌生于预制裂隙处,并随裂隙角度的增加,萌生位置的范围也增大,裂隙尖端微裂纹的集结效应越不明显;裂隙两尖端位置与上(下)部位置的应力峰值之差,随着裂隙角增大而逐渐减小。

In order to study mesoscopic mechanics characteristics and the internal crack development of the fractured sandstone,a uniaxial compression experiment and PFC^(2D) numerical simulation analysis of different angles fractured red sandstone specimens were performed.And evolution of mesoscopic crack simulation and surrounding stress of the fracture were obtained in different angles fractured red sandstone.The results showed that the macro failure mode of complete specimen would be significantly affected by the prefabricated single fracture.Within a certain angle range,the initial crack originated at the prefabricated fracture,and with the increase of the fracture angles,the range of the initiation location increased,also the aggregation effect of the mesoscopic crack at the crack tip became less obvious.The difference of stress peak between the two fractured tips and the upper(lower)part decreased with the increase of fractured angles.