Research on movement and stress transfer law of overburden rock in deep filling mining

WEI Yimei; HUANG Peng; REN Guohui; TENG Xinyong; WANG Wei

doi:10.13347/j.cnki.mkaq.20241516

Abstract：As the shallow coal resources gradually deplete,humans have to develop deeper coal resources.However,with the in-crease in mining depth,the deep mining environment undergoes fundamental changes,primarily characterized by"three highs and one disturbance"(high temperature,high pressure,high gas content,and disturbance).The overburden movement characteristics and the manifestation laws of mining-induced pressure in deep filling mining exhibit significant differences compared to shallow filling mining.In this study,the axial compression characteristics of gangue samples were tested using an electro-hydraulic servo universal testing system and a loading steel barrel device.The chemical composition of the gangue filling material was analyzed by X-ray fluorescence(XRF).The 1303N-1#working face of Xinjulong Coal Mine was selected as the engineering case,and the physical and mechanical parameters of the coal-rock layers in the working face were measured.Using FLAC3D numerical simulation software,a three-dimensional filling mining model of 1303N-1#working face was established to analyze the distribution of vertical stress,strain energy,vertical displacement,and plastic zone under different filling rates.The displacement of the roof,the stress of the filling body,and the deformation of the filling body in 1303N-1#working face were designed and monitored.The numerical results show that with the increase in the filling rate,the advanced support stress of the working face decreases,roof deformation reduces,and the plastic zone shrinks.At the filling rate of 40%,the vertical stress of the immediate roof is higher,with stress concentrated around the coal wall,and the plastic zone extends to 9 meters above the immediate roof,causing rupture.At filling rates of 80%and 90%,the peak value of the support stress of the immediate roof decreases by 46%,and the plastic zone of the immediate roof is either un-developed or insignificant.The immediate roof only experiences bending and subsidence.Monitoring results in 1303N-1#working face indicate that the filling rate of the goaf is 85.4%,with the maximum vertical displacement of the roof reaching 438 mm,and the maximum internal stress of the filling body reaching 14.2 MPa.Filling mining effectively reduces the deformation and stress concen-tration of the overburden.The findings provide theoretical support and engineering reference for deep filling mining.