温度和损伤程度对砂岩渗透特性影响的试验研究

EXPERIMENTAL STUDY ON THE INFLUENCE OF TEMPERATURE AND DAMAGE DEGREE ON THE PERMEABILITY OF SANDSTONE

  • 摘要: 岩石的渗透特性与许多地下工程的稳定与安全有关,而深部岩石工程环境所处的温度、应力以及自身损伤情况对渗透特性也有较大的影响。因此,有必要开展损伤岩石在不同温度、应力情况下渗透特性研究。利用GCTS高温高压动态岩石三轴仪、岩石全自动气体渗透率测试系统,对不同损伤程度砂岩进行了不同围压和实时温度的渗透特性试验。试验结果表明:不同损伤程度砂岩的渗透率与围压之间呈现幂函数负增长关系,在低围压向高围压过渡过程中,高损伤试样渗透率出现较大的跌落;不同损伤程度砂岩渗透率与温度关系为负相关,高损伤试样渗透率随着温度增加下降得更加缓慢;随着损伤程度的增加,砂岩渗透率呈现出低围压情况下先略微下降再上升,高围压情况下逐渐上升的特征。低围压状况下,损伤程度较高的试样之间渗透率差异较大。

     

    Abstract: The permeability of rock is related to the stability and safety of many underground projects. The temperature, stress, and self-damage in the environment of deep rock structures have a great influence on the permeability. Therefore, it is necessary to study the permeability of damaged rock under different temperatures and stresses. Permeability tests of sandstone of different damage degrees under different confining pressures and real-time temperatures were conducted by GCTS high-temperature and high-pressure dynamic rock triaxial apparatus and automatic gas permeability test system. The results show that the relation between the permeability of sandstone with different damage degrees and confining pressures exhibited a negative growth in the form of a power function. In transiting from a low confining pressure to a high confining pressure, the permeability of the highly damaged sample greatly dropped. The relation between the permeability of rock of different damage degrees and temperature was negative. The permeability of the highly damaged specimen was decreased slowly as the temperature went down. With the increase of the damage degree, the permeability of sandstone decreased slowly and then increased under a low confining pressure, and increased gradually under a high confining pressure. In addition, under low confining pressures, the difference of the permeability between the samples of higher damage degrees was larger.

     

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