Abstract:
High-water content materials were widely used in gob-side entry retaining(GER) in thin and medium-thick coal seams under different conditions and some thick coal seams with good conditions, forming a rich practice of surrounding rock control for GER. Based on the theoretical analysis and field practice of GER filled with high-water content materials, with stress control and surrounding rock strengthening as the main lines, the effects of filling and surrounding rock on roadway excavation, advance mining of the working face, adjustment and stability of the surrounding rock and surrounding rock were analyzed. . The stress and deformation characteristics of the four stages were reused in the adjacent working face, and the movement characteristics of the overlying rock roof with “secondary breaking of the basic roof” were proposed. Taking the gob-side entry retaining at the 15102 working face of Qinglong Tongchang Coal Mine as the background, the distribution characteristics of surrounding rock stress and plastic zone in the process of roadway retention were studied by numerical simulations, and it was revealed that the rotation subsidence of overburden main roof of the retained entry was the main source of external force on retained entry combined with numerical simulation. On this basis, the key areas of surrounding rock control of the retained entry were put forward. According to the strong plastic deformation characteristics of the consolidated body of high-water content materials, strengthening mechanism of the surrounding rock by time periods and zones for the retained entry was put forward, reasonable supporting resistance calculation formula of high water material filling body, roof separation calculation formula of roadway retention and supporting strength calculation formula of solid coal seam were determined, and the key parameters calculation of the surrounding rock control for the retained entry filled with high-water content materials was given. The key parameters include the backfill support resistance (backfill width and strength), the strength of the roof support (support in the roadway and temporary support), and support strength of solid coal rib. This paper also introduced two application examples of surrounding rock control of GER filled with high-water content materials in the No.15 coal seam of Tongchang Coal Mine and in the No.9 coal seam in Zhaozhuang Coal Mine of Gaoping City, Shanxi Province. The control effect of surrounding rock deformation of retained entry was good. Finally, the future development of surrounding rock control technology of GER filled with high-water content materials was proposed.