(1. Department of Geotechnical Engineering，Tongji University，Shanghai 200092，China；2. Key Laboratory of Geotechnical and Underground Engineering of Ministry of Education，Tongji University，Shanghai 200092，China；3. Department of Structural Engineering，Nagasaki University，Nagasaki 852–8521，Japan)
Abstract：The evolution of microscopic fabric of rock has an important effect on its mechanical property and failure shape and it is therefore essential to study the microscopic fabric on rock. In this study，the scanning electron microscope(SEM) was used to scan the micro structure of the failure section of samples after compression shear test and Brazil split test. The morphological characteristics of the fracture surface of specimen were highlighted and the criteria of microscopic morphology matching macroscopic mechanical properties of crack surface were established. Meanwhile，the whole failure section of manufactured pre-crack was scanned with different angles of inclination. The criteria was applied to distinguish their microscopic morphology. As a result，the ratio of tensile-shear stresses on the fracture surface was obtained. The variation of the ratio in the cracking propagation process was studied. The results show that the ratio of tensile-shear stresses is closely related to the dip angle of the pre-existing crack. When the inclination angle is less than 45°，the tensile stress on the fracture surface is high，and the ratio decreases with the crack angle increasing. When the inclination angle is more than 45°，the results are opposite to the former. When the inclination angle is 45°，there are two macroscopic cracks owing to the combined effect of tensile and shear stresses. The proportion of wing cracks tensile stress changes from high to low during crack propagation process，and the results of secondary crack are converse to the former.
赵 程1，2，于志敏1，2，王文东1，2，松田浩3，森田千寻3. 基于单轴压缩的岩体破坏机制细观试验研究[J]. 岩石力学与工程学报, 2016, 35(12): 2490-2498.
ZHAO Cheng1，2，YU Zhimin1，2，WANG Wendong1，2，MATSUDA Hiroshi3，MORITA Chihiro3. Meso-experimental study of failure mechanism of rock based on uniaxial compression test. , 2016, 35(12): 2490-2498.
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2016, Vol. 35 
