不同围压三轴循环压缩下岩石的线性储能和耗能规律及损伤演化特征

Linear energy storage and dissipation laws and damage evolution characteristics of rock under triaxial cyclic compression with different confining pressures

为了研究岩石的能量分布规律及其围压效应,开展不同围压下的三轴循环压缩试验。基于所得应力-应变曲线计算不同应力水平下的峰前输入应变能、峰前弹性应变能和峰前耗散应变能。结果表明,不同围压下峰前弹性应变能和峰前耗散应变能与峰前输入应变能呈明显线性相关,从而得到三轴循环压缩下的线性储能和耗能规律。岩石三轴压缩储能系数与围压呈正相关,而对应的耗能系数则相反。利用线性储能规律,可以推导出岩石在三轴压缩作用下的峰值弹性应变能和峰值耗散应变能。此外,基于线性耗能规律分析了不同围压下岩石的损伤演化特征。

Triaxial cyclic compression tests with different confining pressures were conducted to explore the energy distribution characteristics of rock and their responses to confining pressure.The pre-peak input strain energy,pre-peak elastic strain energy,and pre-peak dissipated strain energy at different stress levels were computed based on the resultant stress-strain curves.The results indicated that under different confining pressures,both the pre-peak elastic strain energy and pre-peak dissipated strain energy were linearly related to the pre-peak input strain energy,and thus the linear energy storage and dissipation laws in triaxial cyclic compression were confirmed.The energy storage coefficient in triaxial compression of the rock was positively correlated with the confining pressure,whereas the corresponding energy dissipation coefficient exhibited an opposite correlation.Using the linear energy storage law,the peak elastic strain energy and peak dissipated strain energy of rock in triaxial compression were deduced.Furthermore,the damage evolution characteristics of rock under different confining pressures were analysed by considering the linear energy dissipation law.