摘要
本文以锦屏大理岩为研究对象,采用干湿循环处理,开展不同干湿循环次数和围压加卸载条件下大理岩气体渗透性试验,研究了大理岩渗透率随围压和干湿循环次数的变化规律.同时通过电镜扫描,探究了不同干湿循环作用对大理岩细观结构的影响效应,分析了干湿循环对大理岩的细观作用机理.试验结果表明:气体渗透性试验中,在相同围压下,大理岩渗透率随干湿循环次数的增加而递增,在同一干湿循环次数下,大理岩的渗透率随围压增大而减小;干湿循环次数越高,围压对渗透率的影响效应越显著;随着干湿循环次数增加,微裂纹不断扩展并相互搭接,大理岩块状构造逐步破碎化.
In order to study the permeability of Jinping marble after dry-wet cycling treatment,gas permeability tests under different dry-wet cycles with loading and unloading of confining pressure are carried out.Meanwhile,the effect of dry-wet cycling on the mesostructure of the marble are investigated by scanning electron microscopy(SEM);and the mesoscopic mechanism of wet-dry cycling on the marble is also analyzed.The results show that under the same confining pressure,the permeability of marble increases with the increase of the number of dry-wet cycles;and under the same number of dry-wet cycle,the permeability of marble decreases with the increase of confining pressure.The effect of confining pressure on permeability is significantly enhanced by dry-wet cycling.With the number of dry-wet cycle,the microcracks continue to expand and overlap,and the marble block structure gradually becomes fragmented.
引文
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