某水电站蚀变岩三轴卸荷试验研究

Research on Altered Rock at a Hydropower Station Based on Triaxial Unloading Test

研究蚀变岩在卸荷过程中水对其变形和强度的影响规律。选取西南某水电站右岸坝肩蚀变岩为研究对象,通过扫描电镜获取其微观结构状态和矿物分布;然后对处于天然状态和饱水状态的2种岩样进行三轴加、卸荷试验,分析讨论不同应力路径下水对蚀变岩的应力-应变曲线、变形特性及强度特征的影响规律。结果表明,与加载试验相比,卸荷试验下岩样内聚力增高,内摩擦角减小;饱水状态下蚀变岩三轴加载、卸荷试验的强度均小于天然状态下的强度;蚀变岩遇水后强度明显降低。

In order to study the effects of water on the deformation and strength of the altered rock during unloading,this paper obtains the micro-structure and mineral distribution of the altered rock at the right dam abutment of a hydropower station in southwest China by SEM(scanning electron microscope),then analyzes and discusses the influences of water in different stress paths on the stress-strain curves,deformation characteristics and strength characteristics of altered rock through triaxial loading and unloading tests of rock samples under natural state and saturated state.The results indicate that:compared with loading test,the cohesive force of rock sample increased and its angle of internal friction decreased under unloading test;based on triaxial loading and unloading tests,the strength of altered rock under saturated state is lower than that under natural state;the strength of altered rock decreases obviously after being exposed to water.