Simulation Experimental Study on the Permeability of Coal Rock in Deep Mine

Abstract

By means of MTS electro-hydraulic servo system, specimens from deep coal mine rock are conducted the permeability characteristics experiment under the condition of the stress-strain process and high pore-water pressure, also the results show that both the permeability rate and volumetric strain curves are V shaped, which link the dynamic changes of the microscopic fracture porosity and corresponds with the stress-strain. Meanwhile, under certain external conditions, whether the change of the pore-water pressure can improve the permeability properties or not, it depends on the critical threshold, moreover, the permeability properties under pore-water pressure higher than critical threshold have been improved several times than that at low pore-water pressure, and the peak of strain-permeability rate has a corresponding change with the peak of stress-strain curve, which shows a hysteretic characteristic. The higher the pore-water pressure is, the lower peak strength is needed, the more distinctive effects of dilatation emerge, and the more strain is needed for the appearance of permeability peak, This article provides the basis for the employment of high pore-water pressure to improve the permeability and disaster prevention of coal rock water injection.