Development characteristics and prediction methods of the “three zones” in overlying strata under the 110 mining method

The 110 mining method is a novel coal mining approach that is environmentally friendly. To investigate the movement laws of the overburden strata under the mining conditions of this method, this study systematically analyzed the development characteristics and formation mechanisms of the “three zones” of the overburden strata (caving zone, fractured zone, and flexural subsidence zone). A predictive model for the development height of the “three zones” was established based on the mining damage invariant equation and the pressure arch theory, and a quantitative criterion for the boundary between the caving zone and fractured zone was proposed.To verify the reliability of the model, the 8302 working face of Jinjiazhuang Coal Mine was selected as the research object. A combination of theoretical analysis and on-site monitoring was employed to conduct prediction and in-situ monitoring experiments on the height of the “three zones” and the surface conditions of the goaf. The results show that the relative error between the predicted height of the caving zone by the model and the measured value is +0.38 ​m, and the relative error for the fractured zone height is −1.55 ​m, indicating a high prediction accuracy.The predictive model established in this study provides a theoretical basis for the safe and efficient mining as well as the overburden control in the 110 mining method. The research findings have significant engineering application value for promoting the development of green coal mining technologies.