北皂海域煤矿顶板软岩试样渗透性试验研究

Experimental study on permeability of soft rock of Beizao Coal Mine

针对北皂海域煤矿顶板岩层的隔水性问题,进行了顶板岩样的渗透性试验。根据岩样渗透率变化与其破坏过程的对应关系,分析了全应力-应变过程中岩样渗透性随其变形变化的特点及渗透率-应变和渗透率-应力之间的关联性。结果表明,北皂海域煤矿顶板为典型的软岩,可分为砂岩、泥岩和含粗砾砂岩3组,全应力-应变过程岩样渗透率变化过程可划分为压密-弹性段、峰前屈服段、峰后段3个区间;砂岩与含砾粗砂岩、泥岩相比,其变形破坏曲线更为均匀;用临界抗渗强度与峰值强度的比值或临界抗渗应变与最大渗透率应变的比值能较好反映软岩渗透率变化规律。

Considering the relation between permeability-strain curve and rock failure process of roof of Beizao Coal Mine,the relationship among permeability,strain and stress of rock is analyzed based on the permeability-strain curve and permeability-stress curve under complete stress-strain path.The results show that the rock can be divided to three groups,that is,sandstone,mudstone and sandstone with coarse gravel.The lowest permeability of rock corresponds to its expansion point.The stress-strain path can be divided into three stages,which are compaction-elastic range,yield range of pre-peak and post-peak range.It is proposed that the change of rock permeability is caused by the interaction of the smaller micro-scale level burst,which results in the formation of permeable channels.