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为了深入分析循环加卸载过程中岩石能量耗散演化规律,设计、进行砂岩的单轴循环加卸载试验。详细分析典型循环加卸载滞回圈曲线变化特征,探讨加卸载过程中的总功、弹性变形能、耗散能、能量耗散率、残余应变、损伤变量等参数的变化规律及其相互关系。结果表明:(1)循环加卸载过程中,应力–应变滞后现象明显,而且存在明显的残余应变,在计算各能量参数时应该考虑这些因素的影响;(2)考虑残余变形和滞后效应的影响,提出循环加卸载过程中各能量参数修正的计算方法;(3)岩样在循环加卸载临近破坏的时候,各能量参数及残余应变出现明显的增大,能量参数和残余应变的突变均可以较好地预测岩样的破坏;(4)能量耗散率与残余应变的相关性也从另一个角度说明了在能量参数计算时不可忽略残余应变的影响。研究成果对岩石循环加卸载过程中岩石能量损伤演化规律分析具有较好的参考价值。
In order to further analyze the evolution law of rock energy dissipation during cyclic loading and unloading, a uniaxial cyclic loading and unloading test of sandstone was conducted. The characteristics of the curves of typical cyclic loading / unloading hysteresis loops are analyzed in detail. The variation rules of the total work, elastic deformation energy, dissipative energy, energy dissipation rate, residual strain, damage variables and other parameters in the process of loading and unloading are discussed. The results show that: (1) During the process of cyclic loading and unloading, the stress-strain hysteresis is obvious and there are obvious residual strains. The influence of these factors should be considered when calculating the energy parameters. (2) The influence of residual deformation and lag effect (3) The energy parameters and residual strain of rock samples increase obviously when the cyclic loading and unloading approaches failure, and the abrupt changes of energy parameters and residual strain can be made (4) The correlation between energy dissipation rate and residual strain also shows the influence of residual strain can not be neglected in the energy parameter calculation from another perspective. The research results have a good reference value for the analysis of rock energy damage evolution during rock loading and unloading.