269 / 2018-04-14 02:16:22

Back analysis of coal mine entry roof shock disaster using numerical modelling and field observations

displacement back-analysis,entry roof shock,coal bump,longwall mining

矿山动力灾害 > 岩爆冲击

The Buertai coal mine of the Shendong Coal Mining Group is located in Erdos in Inner Mongolia province, China. It produces 20M tons per annum using longwall mining method. The entry in panel No.42105 suffered from a roof shock incident and a coal bump in the 30m-wide barrier pillar (No. 42) during production. The occurrence of such shock damaged more than 100 hydraulic single props due to the sudden roof pressure increase. This paper investigates the underlying mechanism that led to the entry roof shock disaster at panel No.42105. Finite element modelling software, ABAQUS is used to build a 3D model of the area affected and surrounding longwall face to simulate the roof shock phenomenon using displacement back-analysis method. Based on field ground surface subsidence observation data, the least square objective function is adopted to optimize the input geotechnical parameter values in the displacement back-analysis work. A Mohr-coulomb strain softening model is used to describe the deformation behavior of the roof strata as well as the coal seam. The breakage and movement characteristics of the overlying roof layer are further analyzed based on the numerical simulation results and the overlying rock strata structure. The results indicate that mining of the lower coal seam (No. 42) after the upper seam (No. 22) had been mined out, causes the reactivation of hard rock layer fracturing and movement above the upper level gob of seam No. 22. This appears to generate the dynamic impact onto the No.42 coal pillar.