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Analysis on Mechanical and Dilation Characteristics of Phyllite Rock under Triaxial Compression
(1 Sichuan Bashan Expressway Co., Ltd., Chengdu 610047; 2 Sichuan Expressway Construction & Development Group Co., Ltd.,Chengdu 610047; 3 State Key Laboratory of Geohazard Prevention and Geoenvironment Protection, Chengdu University of Technology,Chengdu 610059)
Abstract Rocks are characterized by dilation in deformation failure process. Taking phyllite rock as the research subject, the indoor rock triaxial compression tests are conducted to reveal the strength and dilation characteristics of jointed phyllite rocks with joint angles of 5°~45°. The results show that (1) the characteristic point stress of the rock increases with the increase of the confining pressure, while the dilation characteristics diminish; (2) the peak stress of the rock decreases as the angle between the joint plane and the maximum principal stress increases; within the range of joint angle from 5° to 45°, the closure stress, cracking stress and damage stress are maximum at θ=5° and minimum at θ=25°, after which, they increase as the angle increases; (3) the dilation characteristics are quantified and described by the dilation indicator Id, which has a confining pressure effect, i.e., the dilation indicator has a good negative exponential distribution with the confining pressure; greater variability in rock dilation rates is seen under various confining pressures at small angles; (4) the md coefficient is linearly related to the angle within the joint angle range of 5°~45°, which can describe the fractal characteristics of the dilation index with the distribution of the confining pressure, reflecting the weakening effect of the angle on the variability of rock dilation with the confining pressure.
Abstract：
Rocks are characterized by dilation in deformation failure process. Taking phyllite rock as the research subject, the indoor rock triaxial compression tests are conducted to reveal the strength and dilation characteristics of jointed phyllite rocks with joint angles of 5°~45°. The results show that (1) the characteristic point stress of the rock increases with the increase of the confining pressure, while the dilation characteristics diminish; (2) the peak stress of the rock decreases as the angle between the joint plane and the maximum principal stress increases; within the range of joint angle from 5° to 45°, the closure stress, cracking stress and damage stress are maximum at θ=5° and minimum at θ=25°, after which, they increase as the angle increases; (3) the dilation characteristics are quantified and described by the dilation indicator Id, which has a confining pressure effect, i.e., the dilation indicator has a good negative exponential distribution with the confining pressure; greater variability in rock dilation rates is seen under various confining pressures at small angles; (4) the md coefficient is linearly related to the angle within the joint angle range of 5°~45°, which can describe the fractal characteristics of the dilation index with the distribution of the confining pressure, reflecting the weakening effect of the angle on the variability of rock dilation with the confining pressure.
Analysis on Mechanical and Dilation Characteristics of Phyllite Rock under
.Analysis on Mechanical and Dilation Characteristics of Phyllite Rock under Triaxial Compression[J] MODERN TUNNELLING TECHNOLOGY, 2021,V58(1): 160-167
2021, Vol. 58 