循环孔隙水压力作用下砂岩变形特性实验研究

Experimental Research on the Deformation Characteristic of Sandstone under the Cyclic Pore Water Pressure

利用MTS815岩石力学试验系统完成了砂岩在循环孔隙水压力作用下的变形特性实验,分析了孔隙水压力下限Pm in、孔隙水压力恒定时间△T以及孔隙水压力循环次数n对砂岩变形特性的影响。实验结果表明:随着孔隙水压力的周期作用,砂岩的轴向应变也呈周期性变化,且随着循环次数的增加,周期性变化规律越明显并逐渐趋于稳定;当轴压、围压以及孔隙水压力均恒定不变时,其轴向应变还将继续变化,且恒定时间越长应变量越大。

This experiment has used the rock mechanics testing system of MTSSI5 to conduct the research on the deformation of rock under cyclic pore water pressure. It has analyzed the influence of lowest stress level Pmin, constant time AT of pore pressure, and the amounts of cyclic loading on the deformation of rocks. The results have showed that the axial strain of the rock will change cyclically with the cyclical influence of the pore water pressure, and with the cycling times increasing, the variation of the cyclic changes is more obvious and gradually moves toward stable. When axial pressure, confining pressure and pore water pressure were constant, the axial strain will continue to change, and the longer the constant time, the greater the strain.