真三轴应力条件下层状复合岩石破坏准则

A failure criterion for layered composite rock under true triaxial stress conditions

为探究层状复合岩石的强度特性,利用均质化理论方法,将层状复合岩石虚拟为一种等效的均质岩石,建立了真三轴应力条件下基于MLC准则的层状复合岩石破坏准则,该准则由层状复合岩石各组分的强度参数以及几何参数来确定;同时,利用自行研制的多功能真三轴流固耦合试验系统,进行细砂岩、粉砂岩、板岩和层状复合岩石在三向不等应力条件(体应力不变,改变应力罗德角、等中主应力系数等σ3)下的真三轴试验,研究层状复合岩石的强度特性以及中间主应力和中主应力系数对复合岩石强度的影响。真三轴试验结果表明,所建立的准则能较好的描述层状复合岩石的强度特征,可为解决层状岩石工程结构的强度及稳定性问题提供了理论参考和依据。

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 σ3-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.