Research on coal and rock seepage laws under different confining pressures and hydraulic pressures

As coal resources gradually enter deep mining,the occurrence conditions of coal and rock are extremely complicated,which seriously affects the seepage characteristics. Based on this study,the seepage characteristics of coal and rock under complex geological conditions,the loading tests of coal specimens were perform ed under different hydraulic pressure and confining pressure using rock permeability analyzer and nuclear magnetic resonance. The seepage flow under different loads was calculated. Based on this,the relationship between permeability,permeability coefficient and confining pressure was analyzed and calculated,and then the coupling effect of seepage field and stress field was analyzed. The results show that: The process of coal seepage under load is divided into three stages: nonlinear stage,nearly linear stage and linear stage. Confining pressure is one of the major influencing factors of coal seepage, and the law of seepage velocity of coal is different under low Co nfining pressure and high confining pressure. In this coal seepage test,when the confining pressure is less than 4 MPa,the seepage change increases linearly and when the seepage change is greater than 4 MPa,it is linear. The pore deformation of coal can be divided into three stages ,and they are rapid pore deformation under pressur e,slow pore deformation under pressure and pore compaction. The research results can provide references for coal seam water inflow estimation.