周期性载荷作用下岩石滞回曲线的演化规律

通过不同加载速率和不同载荷水平的周期性循环载荷作用下细砂岩变形特性的试验研究,探讨了岩石在周期性载荷作用下的变形特性.结果表明:细砂岩在周期性循环载荷作用下的卸载曲线与加载曲线不重合,形成一封闭的滞回曲线,且该滞回曲线在低载荷水平下从第2次循环起逐渐趋于稳定;不同加载速率和不同载荷水平时,周期性循环载荷作用下加、卸载曲线的二次拟合参数从第2次循环起变化不大,并逐渐趋于不变;周期性循环载荷作用下,岩石变形的响应程度与加载速率和载荷水平有关.

Evolution Law of Hysteresis Curve of Rock under Cyclic Loading

To investigate the deformation behaviors of rock the evolution of the hysteresis curve of rock under cyclic loading was studied by the experimental investigation of the deformation characteristics of fine sandstone under cyclic loading at three deformation rates and two stress levels.The research shows that the deformation curve of fine sandstone under unloading does not coincide with the deformation curve for loading to result in a hysteresis curve in the deformation curve,and the hysteresis curve is nearly unchangeable since the 2nd cyclic loading at a low stress level.In addition,fitting parameters of deformation curves for the 1st cyclic loading are different from those for the 2nd cyclic loading at different stress levels and deformation rates,but they tend to be unchanged gradually since the 2nd cyclic loading.Furthermore,the responses of rock deformation to different deformation rates and stress levels under cyclic loading will be different,and the fitting parameters change with deformation rates and stress levels.