三轴压缩载荷作用下单裂隙扩展的CT实时扫描试验

 为研究岩石裂隙在三轴加载作用下的扩展规律，精选出一种与岩石物理力学性质相似的陶瓷制作试件，并在试件中部预置一条圆币状裂隙，进行三轴加载过程中的CT实时扫描试验。采取3种不同区域划分方案，通过对不同层、不同阶段的CT数、CT方差、CT图像的对比分析，获得裂隙被压密、自相似扩展、翼裂纹扩展、微裂纹扩展、裂纹加速扩展直到试件破坏的整个裂隙扩展过程。试验结果表明，在三轴压缩荷载作用下，裂隙被压密较为明显，翼裂纹扩展缓慢，自相似扩展更大，而且翼裂纹的扩展是从自相似扩展后的边缘开始的。总之，预置裂隙的扩展受围压影响很大，扩展过程相当艰难，试件破坏类似于延性破坏。

CT REAL-TIME SCANNING TESTS ON SINGLE CRACK PROPAGATION UNDER TRIAXIAL COMPRESSION

The propagation law of the single crack under triaxial compression is systematically studied through the CT real-time scanning tests. In the tests,through comparison of similar physico-mechanical parameters to the real rock,ceram is selected to precut the test specimens. From the comparative analysis of CT values,CT variances and CT images in different manifold areas,the damage evolution processes,such as the courses of compressed crack,self-similar propagation,wings growth,microcracks propagation,accelerated crack growth and the damage evolution of the specimen failure,of the crack is accurately obtained as follows:the test results show that under triaxial compressive stresses,the crack is obviously compressed at first;then,the propagation of wing crack is restricted,and the self-similar propagation is enlarged by comparison with the uniaxial test result and the propagation of wing crack starts from the edge of self-similar propagation. In conclusion,the propagation of initial crack is influenced obviously by the confining pressure,which makes it slower and similar to ductile failure.