煤岩固液耦合应变－渗透率试验

采用MTS815岩石伺服试验系统进行了煤样全应力应变过程中的渗透性试验.试验结果表明，煤岩的应变－渗透率变化曲线与其全应力－应变曲线变化趋势基本一致，但表现出相对“滞后”的特点，表明渗透率的变化与其损伤演化过程密切相关，同时煤体通过其内部裂隙的渗透需要一定的时间过程，煤岩体达到峰值强度及之后的软化阶段，即损伤变量达一定值时，渗透率出现峰值.根据试验结果，拟合得出了煤岩应变－渗透率分段曲线方程.由于煤岩微孔隙裂隙相对较发育，其渗透率受有效围压的影响较明显，随有效围压增大，煤岩渗透率总体上呈下降趋势，这主要与煤岩中发育的原生裂隙受围压压密闭合以及限制了新生裂隙的扩展和张开度有关.

Experimental of coal's strain-permeability rate under solid and liquid coupling condition

The permeability test of coal during the whole stressstrain process was carried out on MTS815 servo-controlled rock mechanical test system.The development trend between strain-permeability rate curve and whole stress-strain curve of coal is identical on the whole,except that the former puts up "hysteretic" characteristic relatively,which indicates that the development of permeability rate closely relates with the evolvement of damage.At the same time,the permeating through the internal of coal needs a certain time.The permeability arrived its peak value when the coal arrived the softened stage after the peak strength,namely,the damage variable arrived a certain value.According to the test results,the segmental curve equations of strain-permeability were fitted.Because micro holes and cracks are relatively well developed,coal's permeability rate is influenced by confining pressure obviously,and the coal's permeability rate presents downtrend in the whole along with the increase of confining pressure,this mainly dues to the primary fracture in the coal was compressed and closed by confining pressure,and the expanding and opening of new fracture was restricted.