大理岩加卸载试验变形及能量转换研究

Study on Deformation and Energy Characteristics of Marble during Loading and Unloading

摘要: 对大理岩进行常规三轴以及峰前、峰后恒轴压卸围压破坏试验，研究岩石在不同应力路径下的力学特性及破坏过程中的能量演化规律，得到结论：岩样在卸荷过程中产生的环向与体积应变很大，而轴向应变很小，扩容现象明显；围压对能量耗散起抑制作用，从而延缓弹性应变能的释放，这种现象在常规三轴试验中尤为明显，而在卸荷路径下，弹性应变能释放速率加快，模型破坏更加剧烈；常规三轴试验中,应变软化阶段消耗的能量值最多。峰前卸荷岩样在平台期结束后消耗能量值最多。峰后卸荷岩样在平台期结束位置，耗散能曲线增长率明显减小，表明在此之前，主剪切面基本形成，不需要再消耗大量能量。

Abstract: The conventional triaxial test of the marble samples and the failure test of constant axial pressure unloading and confining pressure before and after the peak were carried out to study the mechanical properties of the rock under different stress paths and the energy evolution law during the failure process. The hoop and volume strain generated during the unloading process are large, while the axial strain is small, and the expansion phenomenon is obvious; the confining pressure suppresses the energy dissipation, thereby delaying the release of elastic strain energy. This phenomenon is found in conventional triaxial. It is particularly obvious in the test, and under the unloading path, the elastic strain energy release rate is accelerated, and the model is more violently damaged; in the conventional triaxial test, the energy value consumed in the strain softening stage is the most. The unloaded rock sample before the peak consumes the most energy value after the end of the platform period. After the peak unloading, rock sample is at the end of the platform period, the growth rate of the dissipated energy curve is significantly reduced, indicating that before this, the main shear plane is basically formed, and no more energy is needed.