Research on the integrated technology of bearing structure reconstruction and support control in high risk area of top coal roadway in thick coal seam

In order to address the problems of easy breakage of surrounding rock, large roof subsidence and frequent roof falling and rib spalling in the high roof area and structural belt of the top-coal caving roadway in thick coal seam, the research on the surrounding rock control technology of the top-coal caving roadway in thick coal seam is carried out by means of field investigation, laboratory test, theoretical analysis, numerical simulation and industrial-scale test, taking the grout transport crossheading of I040905 working face of a coal mine as the engineering background. The geological characteristics and deformation and failure characteristics of the roadway were clarified through field investigation, and the physical and mechanical parameters of the surrounding rock were determined by laboratory tests. Based on theoretical analysis, the mechanical model of the roof of the top-coal caving roadway is established, and the deformation and failure mechanism of roof and roadway side and the synergistic deformation law of roof and side are revealed. The influence of top coal thickness and strength on the stability of surrounding rock is analyzed by FLAC3D. The combined control technology of ' advanced duct pre-grouting and bolt-cable combined support ' is proposed, and the support parameters are optimized. The test results show that technology can effectively control the deformation of the roadway. The maximum subsidence of the roof is 111.6 mm, and the maximum displacement of the two ribs is 85.3 mm. The force of the bolt (cable) is uniform and stable, which greatly improves the efficiency of roadway excavation. It successfully addresses the problem of safe excavation in the high roof area and structural belt of the top-coal caving roadway in thick coal seam, providing a theoretical basis and practical engineering reference for similar roadways. The research results will also contribute to human safety and environmental protection in coal mining operations.