单轴压缩下岩石全应力应变过程中能量演化特征

Characteristics of energy evolution during total stress-strain in rocks under uniaxial compression

为了探究不同岩性岩石单轴压缩下能量演化规律,对花岗岩、砂岩和煤进行了单轴压缩和单轴分级加卸载试验,得到了不同条件下的应力-应变曲线;利用积分和公式获得了岩石试样不同条件下全过程的总能量密度、弹性能密度和耗散能密度值;分析岩石试样峰前和峰后能量演化特征,探究单轴压缩弹性能密度与总能量密度之间的关系。结果表明:单轴分级加卸载应力-应变曲线的外包络线和其单轴压缩曲线具有相同趋势,整体存在一定的偏离程度,且密实度越大的岩石,其偏离程度越小;岩石试样的弹性能密度和总能量密度在单轴压缩与单轴分级加卸载下均满足线性储能规律,利用线性储能规律,得到了岩石单轴分级加卸载与单轴压缩储能极限,两者几乎相等,并且岩石强度越大其储能极限越大。

To study the energy evolution of rocks under uniaxial compression, uniaxial compression and uniaxial step loading and unloading tests were performed on granite, sandstone, and coal, and the stress-strain curves under different conditions were obtained. The total energy density, elastic energy density and dissipation energy density for the whole process of rock specimens under different conditions were obtained by using the integral and formula. The energy evolution characteristics of rock specimens before and after the peak were analyzed, and the relationship between elastic energy density and total energy density under uniaxial compression were investigated. The results show that the outer envelope of the uniaxial step loading and unloading stress-strain curves have the same trend as the uniaxial compression curves, and the overall deviation exists to a certain extent, and the greater the density of the rock, the smaller the deviation is. The elastic energy density and total energy density of the rock specimens satisfy the linear energy storage law under uniaxial compression and uniaxial step loading and unloading. The energy storage limit of uniaxial compression and uniaxial step loading and unloading, which are almost equal, is obtained by using the linear energy storage law, and the greater the strength of the rock is, the greater the energy storage limit is.