Research on Failure Characteristics of Interlayer Water‐Resisting Rock Strata and Water Inrush Evaluation in Roof Goafs Under Deep and Shallow Repeated Mining

To address the risk of water inrush from old water‐logged goafs during deep and shallow repeated mining, this study investigates the failure characteristics of interlayer water‐resisting rock strata and establishes a corresponding water inrush evaluation method. Based on the roof and floor failure characteristic theories, the failure zoning of interlayer rock strata was distinguished for shallow and deep mining by analyzing their different stress environments and boundary conditions, and the applicable calculation formulas for each zoning index were proposed. For deep mining, the elliptical boundary of the depressurization zone and the tangential stress expression along the ellipse were defined, while the parabolic boundary of the stress concentration zone was determined using three characteristic stress points of the surrounding rock. A case study of a shallow repeated mining coal mine in Shanxi Province was conducted to calculate the failure zoning parameters of interlayer rock strata, identify the formation of water‐conducting channels by the main key layer position, and derive the quantitative relationship between the initial fracture span of the main key layer and the goaf water accumulation height based on the elastic plate theory. The results clarify the differential failure mechanisms of interlayer water‐resisting rock strata under shallow and deep repeated mining. The proposed evaluation method offers a theoretical basis and engineering reference for preventing and controlling roof goaf water inrush in coal mines.