不同围压下板岩三轴压缩过程能量及损伤分析

根据不同围压下板岩三轴试验的结果，研究不同围压下板岩的能量变化规律和损伤分析。研究结果表明，不同变形阶段板岩的弹性应变能、耗散能的变化情况不同，弹性应变能先增加后减小，耗散能加载初期几乎为零，进入屈服段急剧增加。根据弹性应变能与总吸收能之比将岩石压缩过程中裂隙发展划分为3个阶段:裂隙稳定发展阶段、裂隙加速发展阶段和裂隙贯通阶段。岩样破坏后总吸收能、耗散能与围压的关系表明，从开始加载到屈服段，畸变比能和体变比能之和Ue'大体等于弹性应变能Ue；从屈服段到峰值强度，Ue'小于Ue且差值越来越大。从能量角度定义损伤变量，认为:低围压状态对应较低的耗散能、较高的损伤值；高围压状态对应较高的耗散能、较低的损伤值。 

Energy and damage analysis of slate during triaxial compression under different confining pressures

According to the results of slate triaxial compression tests under different confining pressures, slate's failure and energy variation under different confining pressures are analyzed. The results show that elastic energy and dissipation energy have different change situation when slate is at different deformation stages. The elastic energy increases firstly and then decreases, dissipation energy at the beginning of loading is almost zero, increases rapidly at yield stage. Considering the ratio of elastic energy and the total energy absorbed, development of fracture is divided into three stages in the process of compression:steady development stage, accelerated development stage and connecting stage. Linear formula of rock samples are obtained by fitting the total absorbed energy, dissipation energy and confining pressure. When loading to yield strength stage, Ue' is almost equal to Ue; When loading to peak strength stage, Ue' is less than Ue, and the difference is growing. By defining damage variable from the view of energy, we can draw conclusions that low confining pressure state corresponds to low energy dissipation and high damage variable; otherwise, high confining pressure state corresponds to high energy dissipation and low damage variable.