全应力-应变过程中煤岩渗透系数演化规律

Evolution of permeability coefficient of coal rock during compression

瓦斯抽采是治理高瓦斯和突出煤层的有效手段.在应力和钻孔扰动的作用下,瓦斯抽采孔周围的煤岩体会产生屈服和破坏,这部分煤岩体的渗透特性对瓦斯抽采效果有直接影响.本文对全应力-应变过程中煤岩的渗透特性进行了试验研究,研究结果表明:煤岩渗透性与其损伤程度关系密切,损伤越大其渗透系数越大;峰后渗透系数比峰前大1-2个数量级.

Gas extraction is an effective means to control the high gas and outburst of coal seam.Under the actions of in -situ stress and borehole disturbances,the coal rock surrounding the gas drainage holes will suffer from yield or failure.The permeability of the failure or yield coal rock will have direct impact on the gas drainage effect.A series of experimental studies have been carried out on the permeability of coal rock under compression.Some conclusions are drawn as follows：（1 ）the permeability of coal rock is closely related to its damage degree,and its permeability evolution law agrees with its damage evolution law;（2）the permeability coefficient in the post -peak stage is much higher than that in the pre -peak stage.