Analysis of shaft lining water irruption mechanism in coal mine based on fluid-solid coupling theory

Abstract：As porous medium,concretes of shaft lining were affected by groundwater seepage.Unified strength theory and elasto-plastic damage model were used to obtain the stress distribution of the elastic zone and plastic damage zone of shaft lining,and the analytical expression of the relationship between p0（the groundwater pressure which shaft lining can bear） and c（the plastic damage zone radius）.According to the theory of limit point of stability,the instability condition of the shaft lining water inrush was put forward.At the same time,curves were drawn between different φ（concrete porosity） and λ/E（the ratio of concrete damage softening modulus and Young’s modulus） values with p0 and c.The results show that the critical groundwater pressure p0c which the shaft lining can bear is 31.9 MPa without considering the impact of groundwater seepage in the shaft lining（φ=0）;when φ takes 0.4,p0c to 15.1 MPa,the critical groundwater pressure p0c decreases 52.7%.When λ/E takes 0.5,p0c to 30.5 MPa,when λ/E takes 2.5,p0c to 18.6 MPa,the critical groundwater pressure p0c decreases 39.0%.Thus,under considering the impact of groundwater seepage in the shaft lining,the groundwater seepage effect is very significant for the critical groundwater pressure p0c.With the increase of concrete porosity φ and the ratio of concrete damage softening modulus and Young’s modulus λ/E,the critical groundwater pressure p0c decreases