Mechanism and disaster control new technology of strong ground pressure manifestation in ultra‐large mining face

Abstract Influenced by the superposition of mining on double key strata, the gob‐side entry in the fully mechanized top‐coal caving mining of extra‐thick coal seams is highly susceptible to severe ground pressure phenomena, such as rock bursts and significant roadway deformations. This area represents a critical focus for prevention and control during the mining process. Therefore, this article focuses on the fully mechanized caving mining of thick coal seams at the Caojiatan mine. It analyzes the distribution and migration characteristics of the key stratum in the overlying stratum and establishes a mechanical model of the transverse pressure bearing structure in the mining area. The analysis covers the transition of the transverse pressure bearing structure through four states, from a virtually stable state to an unstable state, filling the gap left by traditional S‐R theory in analyzing the transverse pressure bearing structure in the mining area, and revealing the mechanism of strong mining pressure manifestation along the gob‐side entry in the ultra‐thick coal seam under the influence of double key strata. The results indicate that the main factors affecting the manifestation of strong mining pressure along the goaf are the pressure‐boosting effect caused by the instability of the double‐key strata, the excessively long cantilever length of the lateral pressure‐bearing structure, and the underfilling of the goaf gangue. To this end, a combination of directional energy accumulation blasting and enhanced blasting for roof cutting and pressure relief technology was proposed to reduce the cantilever length of the pressure‐bearing structure and increase the filling degree of collapsed gangue, thereby reducing the pressure of the roadway to control deformation. The effect of this technology was comprehensively studied using numerical simulation and on‐site experiments, verifying the effectiveness of this technology in controlling the deformation of the roadway surrounding rock. The peak pressure decreased by a maximum of 18.5%, and the average step distance decreased by 41%. The maximum reduction in tunnel deformation is 81.9%. This study provides a scientific basis for the deformation control of the roadway under similar conditions.