不同应力路径下岩石卸荷破坏过程的变形特性与能量耗散分析

Analysis on deformation properties and energy dissipation of rock unloading failure process under different stress path

基于能量原理和MTS试验机进行了三种不同应力路径下花岗岩卸载试验,研究了卸荷条件下岩石的应力—应变全过程曲线变形特征和岩样卸围压破坏过程的能量耗散规律。研究结果表明,在卸围压过程中,岩样侧向变形明显大于轴向变形,即表现为明显的侧向扩容,且方案3>方案1>方案2;能量耗散与时间呈非线性关系,且在卸围压试验中,施加围压越大,在相同侧向变形水平下能量耗散越大;在同一卸载方式下岩石耗散能随着围压的增大而增大。其研究结果对从能量角度研究卸载岩石力学特性有一定的指导作用。

Through the granite unloading tests under three different stress paths （three schemes）, the deformation properties of rock stress-strain curves under unloading conditions and the energy dissipation law in the rock sample destruction process of unloading confining pressure were studied. The results showed that in the process of unloading confining pressure, the lateral deformation of rock samples was significantly greater than the axial deformation, namely appearing as significant lateral expansion, and scheme 3 〉 scheme 1 〉 scheme 2. The energy dissipation and time showed nonlinear relationship, and in unloading confining pressure test, the greater was the applied confining pressure, the greater was the energy dissipation at the same level of lateral deformation. In the same unloaded manner, the rock dissipated energy increased with the increase of confining pressure. From the energy point of view, the findings on researching unloading rock mechanical properties have some guidance.