Study on the evolutionary mechanism and synergistic control technology of floor heave in deep high-stress roadways

To address floor heave control in deep high-stress roadways, this study established a slip-line field model of the roadway floor based on plastic mechanics. The quantitative relationships between floor failure depth, internal friction angle, and coal seam parameters were derived, and the linear positive correlation between floor heave magnitude and both the rib-side limit equilibrium zone width and floor failure depth was clarified. An engineering case from the tailgate of Panel 1802 in Xinzhuang Coal Mine revealed four-stage failure characteristics of high-stress roadway floor heave. Field measurements showed that the influence range of advance abutment stress extended to approximately 90 m, and a 109° deflection in the azimuth of principal stress σ 1 intensified shear slip in the floor. The vertical stress peak of 15.2 MPa at the floor corners triggered initial failure, while the continuous increase in deep horizontal stress to 7.2 MPa was the main cause of floor heave. The proposed “shallow pressure relief-deep anchoring” collaborative control system reduced vertical stress peaks by 33%–38% through pressure-relief grooves and decreased the horizontal stress concentration peak by 60% to 4.7 MPa through bottom-corner cable anchoring, reducing floor heave from 510 mm to 150 mm. Numerical simulations and field monitoring confirmed that this strategy transformed the plastic failure pattern from inverted triangular composite failure to localized shear failure at groove shoulders by inducing bimodal stress redistribution and reinforcing the surrounding rock structure. The roof-to-floor convergence stabilized at 37.4 cm, providing both theoretical foundation and engineering paradigm for floor heave control in deep roadways.