LI D Y, WANG Y C, WANG S,et al.Numerical simulation study of top-coal loss mechanism and reasonable cycle step length for extra-thick coal seam top-coal drawing[J].Journal of Henan Polytechnic University(Natural Science) ,2023,42(2):1-10.

doi:10.16186/j.cnki.1673-9787.2021010045

Received:2021/01/10

Revised:2021/05/18

Published:2023/03/25

Numerical simulation study of top-coal loss mechanism and reasonable cycle step length for extra-thick coal seam top-coal drawing

LI Dongyin1, WANG Yaochuang1, WANG Shen1,2, ZHU Shiting3, WANG Zuguang1

1.School of Energy Science and Engineering，Henan Polytechnic University，Jiaozuo  454000，Henan，China；2.Postdoctoral Station of Safety Science and Engineering，Henan Polytechnic University，Jiaozuo  454000，Henan，China；3.Tongxin Coal Mine，Datong Coal Mine Group Co.，Ltd.，Datong  037003，Shanxi，China

Abstract:In order to study the reasonable value of the parameters of the cycle step length（CLS）in fully-mechanized top-coal drawing of extra-thick coal seam，and to explore the influence of CLS on top-coal loss mechanism and top-coal recovery rate，CDEM particle block element coupling numerical simulation method，taking the 8222 fully mechanized top-coal drawing face of Tashan Coal Mine as the engineering background，the CDEM particle block element coupling numerical simulation method was adopted to establishe the mathematical model considering the support effect of hydraulic support.The two-dimensional strike mining numerical model was used to analyze the coal cycling step length，the shape of residual coal，the coal funnel，and the coal rock interface line.The mechanism of top-coal loss was revealed under the condition of “rock apear，close the opening”，and the strip loss law of top coal with the advance of circulation in the goaf was found.The results showed that：With the continuous advance of the working face，the rock above the hydraulic support reaches the coal drawing mouth in advance，and part of the top coal on one side of the goaf fails to be discharged and remained in the goaf，resulting in the loss of top coal.The distance of drawing coal had a significant effect on the interface shape of coal and rock and the mutual invasion of coal and rock，and then affected the top-coal recovery rate and mixed rock rate.In addition，the evolution law of coal-rock interface line and top-coal recovery rate under the conditions of different cycling lengths were analyzed.Through numerical analysis and according to the top-coal recovery rate and total recovery index，the best cycling length was 0.8 m under 12 m top coal back end thickness in 8222 fully mechanized top-coal drawing face of Tashan Coal Mine.

Key words:top-coal drawing;cycle step length;extra-thick coal seam;particle-block element coupling approach;top-coal recovery rate

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