Surrounding rock control technology by pressure relief stress transfer reinforce in three-soft coal seam under strong dynamic pressure

Aiming at the technical problem of difficult control of surrounding rock in the three-soft coal seam under the influence of strong dynamic pressure, taking the No.115-101 tail entry in the three-soft coal seam of Zhongheng Coal Mine as the engineering background, according to the actual situation, UDEC numerical software was used to establish a numerical model by field investigation, loosening of surrounding rock, and in-situ stress test, the causes of roadway deformation and failure are studied, and based on the principle of stress control, a comprehensive control theory of pressure relief stress transfer reinforce surrounding rock in three-soft coal seam roadway affected by strong dynamic pressure is proposed. The research results show that the loose circle of surrounding rock of No.115-101 tail entry is in the range of 0～5 m, and the stress concentration range is 5～6 m of surrounding rock. The surrounding rock control technology of pressure relief stress transfer reinforce is adopted, which is under the condition of profiled original 29U steel support, reduce the support row spacing, design and construct blasting pressure relief holes according to the inclination and thickness of the coal seam, install explosives at the bottom of the hole, and use self-made hole sealing equipment to press the reinforcement material into the hole through high pressure wind to seal the hole and implement blasting. After blasting, the surrounding rock stress is redistributed to re-form the broken zone, plastic zone and elastic zone, and the elastic zone of stress concentration is transferred to the deeper surrounding rock, reducing the stress concentration of the surrounding rock in the shallow part of the roadway and floor, a low-stress relief ring is formed in a certain range of the surface around the roadway, and a self-supporting ring with concentrated stress is formed in the deep part of the surrounding rock, and the concentrated stress is mainly borne by the rock mass of the self-supporting ring. The rock mass of the self-supporting ring is in the deep part of the surrounding rock and is basically in a three-dimensional stress state, which reduces the destructive effect of concentrated stress on the roadway and greatly improves the stability. Finally, the approaching rate of the roof and floor of the roadway surrounding rock was reduced by 79.43%, and the approaching rate of the two sides was decreased by 54.17%, the deformation of the surrounding rock of the roadway was significantly reduced, effectively controlling the surrounding rock deformation of the three-soft coal seam under the influence of strong dynamic pressure.