Experimental Study on Seepage Characteristics of Coal Containing Gas and Water

The effect of gas drainage is often affected by water after hydraulic infiltration enhancement measures are adopted for soft and weak permeability coal. In order to understand the characteristics coal in state water, a three-phase pipe domain model established. Using improved triaxial seepage test platform, three groups cyclic tests under different pressure injection conditions carried out on raw samples constant temperature, fixed axial pressure, confining pressure. results show that (1) circulating samples, moisture content each group different. change trend first cycle natural sample second pressureless similar which decreases slowly with increase third increases from two cycles. (2) ultrasonic wave velocity injection, longitudinal opposite is, When 0.9 MPa 1.0 MPa, reduction more significant. (3) During test, when less than 1.11 sensitivity coefficient pressurized lower there an inflection point; higher