Influence analysis of between subsidence and structure evolution in overburden rock under mining

In order to understand the failure characteristics of overburden strata in underground coal mine goaf and its influence on surface subsidence, and accurately predict surface movement deformation, according to different mining progress, the structural change characteristics of overburden strata were analyzed from the perspective of soil mechanics and material mechanics, which were generalized into three types of shape beam models:simply supported beam, cantilever beam and masonry beam.Based on the failure state of overburden structure in different stages, the evolution law between stages was analyzed in detail, and the deformation formula of overburden structure in each stage was deduced according to the beam deformation theory.Combining the net space transmission attenuation effect of abscission layer in mined-out area with its own dynamic development process, a fully mining from production to the development of the gateway as the super full mathematical model of the mining gateway was established, and the abscission layer of overburden stratum at the lateral width was deduced.According to the dynamic change in the final phase of the gateway and the development of the lateral width, through the horizontal width of abscission layer as the next across the empty distance of overburden beam model, the theoretical model of surface deformation and subsidence with delamination and under-fill delamination was designed.In order to highlight the consistency of deriving the theoretical prediction model, the theoretical prediction model was verified by combining the measured data with the numerical simulation method.The numerical simulation model was established by combining the measured data of Sandaogou coal mine, and the maximum relative error was 5.8% compared with the measured data, which was within the allowable error.After that, the theoretical prediction model result and the numerical simulation result were verified to prove the rationality of the theoretical prediction model.