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采用恒定应力水平下的变形初期渗流和变形后期渗流2种试验方案,对初始孔隙率基本相同的饱和破碎砂岩进行了5级应力水平下恒载变形过程中不同流速的渗透试验,探索不同阶段的变形与渗流的相互影响;得到了岩样在不同应力水平下的孔隙率时间曲线、孔压梯度与渗流速度关系曲线以及轴向应力与恒载终点孔隙率关系曲线等.研究表明:1)恒定应力水平下破碎砂岩的孔隙率时间曲线可用对数函数拟合;2)变形初期渗流中的岩样在渗流时具有相对较高的孔隙压力,其孔隙压力时间曲线在相同流速下不易达到稳定状态,其终点孔隙率明显超出变形后期渗流中相应的数值;3)变形趋于稳定时破碎岩石中的渗流满足Forchheimer关系式.
Two kinds of experimental schemes of initial deformation and post-deformation seepage at constant stress level were used to investigate the different flow rates of saturated fractured sandstone with constant initial load at 5-level stress level. The interaction between deformation and seepage, the porosity time curve of rock samples at different stress levels, the relationship curve of pore pressure gradient and seepage velocity, the relationship between axial stress and dead end porosity, etc. The results show that: 1) constant The porosity time curve of fractured sandstone can be fitted by logarithmic function under stress level. (2) The rock samples in seepage flow have a relatively higher pore pressure during seepage, and the pore pressure time curve is not stable at the same flow rate , Whose ultimate porosity is obviously beyond the corresponding value in the seepage at the late stage of deformation. 3) The flow in the crushed rock meets the Forchheimer equation when the deformation tends to be stable.