Study Of Surrounding Rock Deformation And Pressure-relief Mining Of Gently Inclined And Multilayer Deposits By Filling Mining In Shanghengshan Mine

The contradiction between interaction disturbances of different rock mining andsafety-efficiency mining is serious, and ground pressure control is difficult in gentlyinclined and multilayer deposits underground mining. In order to ensure the safety andefficiency of mining, the research of surrounding rock deformation and pressure-relieftechnology is necessary. Based on the Shanghengshan gently inclined and multilayerdeposits, deformation characteristics of surrounding rock were analyzed by usingcomprehensive method, which contain numerical simulation, similar simulationexperiment and theoretical study. Depended on the principle of minimum surroundingrock deformation of underground engineering, pressure relief technique for regional andlocal were researched.Firstly, different proportions of aggregate and adhesive materials of low strengthsimilar material were developed by similar proportioning test, and the influences ofsand-binder ratio and cement content of cemented material on similar materialproperties were analyzed. Four feasible and effective proportions of similar materialswere determined and a multilayer shale deposits model was established based oncondition of deposit and experimental. Numerical simulation model with the sameconstraints of physical simulation model was constructed by using numerical simulationsoftware of Phase2, which provide the foundation of gently inclined and multilayerdeposits underground mining study.Then, depended on pillar stress characteristics in strip mining, Westergaard stressfunction of crack tip on pillar where stope on both sides of pillar are extracted weredetermined based on the-II mixed mode fracture criterion. Boundary conditions offailure region in surrounding rock were calculated according to H-B strength criterion,and damaged width model of pillar was constructed finally. The effectiveness ofcalculation model was verified by digital image processing (DIP). Based on the pillarinfluenced by underground stress and mining disturbance in similar simulationexperiment, and cracks development features of pillar were analyzed, which provide aquantitative basis for the design of underground strip mining of strip pillar width.Finally, characteristics of regional surrounding rock deformation were analyzed inthe conditions of two typical pressure relief mining scheme of regional sequence network, which contain mining sequence and mining intensity. The optimal exploitationscheme, advancing mining sequence and mining intensity of3strips were mined at thesame time, were chosen. Considering the stress concentration of undergroundengineering, strike-drift in footwall rocks was determined as local stress concentrationregion. Effect of local pressure relief technology was discussed, and chosen thedepressurized-borehole along the inclined arrangement and short depressurized-lanenear the side wall layout as the optimal scheme by numerical simulation analysis.Research results enrich the application research of gently inclined and multilayerdeposits filling mining, forming an integrated technology of regional and local pressurerelief, and provide some theoretical and practical significance of the safety andefficiency of underground mining.