(1. State Key Laboratory of Coal Mine Disaster Dynamics and Control，Chongqing University，Chongqing 400030，China；2. College of Resources and Environmental Sciences，Chongqing University，Chongqing 400030，China；3. State and Local Joint Engineering Laboratory of Methane Drainage in Complex Coal Gas Seam，Chongqing University，Chongqing 400030，China)
Abstract：In order to explore the strength characteristics of stratified composite rock，a homogenization procedure was undertaken to convert the layered composite rock into an equivalent homogeneous one and an failure criterion based on the MLC failure criterion under true triaxial condition was established in terms of the strength and geometric parameters. A large number of tests on sandstone，siltstone，slate and composite rock under different true triaxial conditions(changing lode?s angle and ?3- and coefficient of intermediate principal stress-constant tests) were carried out with the multi-functional experiment system built in-house for fluid-solid coupling under true triaxial condition to investigate the effect of coefficient of intermediate principal stress on strengths. The results showed that the proposed criterion for layered composite rock described with fair accuracy the ultimate behaviour of layered rocks subjected to the true triaxial conditions.
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2017, Vol. 36 
