科研之友
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摘要
Bedded rock has a significant bedding plane structure. The direction of bedding plane determines the anisotropy of rock, and the strength of anisotropy is determined by the difference of rock physical properties and the connection strength of adjacent layers, its bedding structure nature of the vulnerability to the impact of weathering effects such as freeze-thaw(FT)cycles. In this research, bedded sandstone specimens with different bedding dip angles were tested by rock triaxial test system(GCTS)after 0, 10, 20, 30 and 40 FT cycles and under confining pressures of 0, 5, 15, 25 and 40 MPa. The test results show that the FT cycles causes cracks in the rock bedding plane, and shear slip failure along the bedding plane is more likely to occur. After 40 times of FT cycles, the uniaxial compressive strength of the specimen with β=0° decreased by 14. 5%, while the specimen with β=67. 5° decreased by 57. 9%, which enhanced the inherent anisotropy of the bedded rock. The influence of confining pressure on rock anisotropy is related to its inherent anisotropy, which shows that with the accumulation of freeze-thaw cycles, the stress-induced anisotropy of rock under confining pressure changes from initial enhancement to inhibition. This study provides theoretical basis for the design, construction and safe operation of bedded rock engineering in cold regions.
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单位冻土工程国家重点实验室; 中国科学院大学
