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从可释放弹性应变能角度对岩石卸围压条件下破坏特性进行研究,利用MTS815电液压伺服可控制刚性试验机进行保持轴向变形不变的卸围压试验,根据卸围压试验数据,分析了该砂岩卸围压过程中变形、强度、弹性模量及能量变化特征。结果表明:随着围压逐渐降低,岩样发生侧向不断扩容;轴向应力逐渐降低,呈现出非线性特征;弹性模量在初始阶段几乎不变化,越过破坏点之后大幅降低;可释放的弹性应变能在初始阶段增大比较缓慢,当围压降低至一定程度时急剧增大;推导出基于可释放弹性应变能的卸荷岩石的整体破坏准则Ue0。
From the perspective of the release of elastic strain energy, the failure characteristics of rock under unloading confining pressure were studied, and the MTS815 electro-hydraulic servo controllable rigid testing machine was used to carry out the unloading confining pressure test to keep the axial deformation unchanged. According to the unloading confining pressure test data, The characteristics of deformation, strength, elastic modulus and energy change during the unloading confining pressure of the sandstone. The results show that with the decrease of confining pressure, the rock specimen expands laterally; the axial stress decreases gradually and shows a nonlinear characteristic; the elastic modulus hardly changes in the initial stage and decreases sharply after the failure point; and the releasable The elastic strain energy increases slowly at the initial stage and sharply increases when the confining pressure decreases to a certain extent. The global failure criterion Ue0 of unloading rock based on the elastic energy of release strain is deduced.