Strata movement and surface subsidence prediction model of deep backfilling mining

Abstract

ABSTRACT Surface subsidence prediction is an important approach to evaluate the surface damages caused by backfilling mining activities, and is applied to guide the recovery of coal resources under buildings, railways, and water bodies. With the mining depth increasing, the mining-induced stress and bedrock ratio increase, which lead to a different strata movement rule from shallow mining. Therefore, the appropriate surface subsidence prediction method for deep backfilling mining needs to be developed. To solve this issue, the coupled simulation method is employed to investigate the features of strata structure, strata movements, and internal strata movement boundary of deep backfilling mining. The simulation results show that the overburden is relatively integrated, and the subsidence of overburden is continuous. Compared with shallow mining, the curve of internal strata movement boundary of deep backfilling is more moderate, which is in accordance with an exponential function. Based on the simulation results, the strata movement prediction model of deep backfilling mining is established with the combination of elastic foundation theory and subsidence space conservation principle, and the prediction subsidence curve basically coincides with the simulation result. This model is highly instrumental in ground environmental protection.