ZHANG W H, LI D Y, WANG S,et al.Study on block-particle coupling approach for modeling progressive failure of top coal in extra thick coal seams[J].Journal of Henan Polytechnic University(Natural Science) ,2022,41(6):24-35.

doi:10.16186/j.cnki.1673-9787.2021020042

Received:2021/02/22

Revised:2021/03/22

Published:2022/11/25

Study on block-particle coupling approach for modeling progressive failure of top coal in extra thick coal seams

ZHANG Wenhui1, LI Dongyin1, WANG Shen1,2, LI Huamin1, ZHU Shiting3, SUN Kaixuan1, ZHANG Weiyu4

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.Tongmei Guodian Tongxin Coal Mine Co.，Ltd.，Datong Coal Mining Group，Datong  037001，Shanxi，China；4.Zhaozhuang Coal Mine Jinneng Holding Group，Jincheng  048000，Shanxi，China

Abstract:In order to study the progressive failure behavior of top coal along with the mining process in the process of fully mechanized top coal caving with large mining height in extra thick coal seam，a 3D numerical simulation method of dynamic coupling of FLAC3D block and PFC3D particles was realized.Considering the collaborative effect of multiple hydraulic supports，the control algorithm of moving support and caving port was compiled by using Fish language，and the monitoring program of top coal damage fracture was developed based on discrete fracture network model realize the visualization of top coal fracture development process.The engineering scale three-dimensional numerical simulation of the whole process of top coal fracturing，crushing and loose body release could be zccurately realized with less calculation time and running memory.The results showed that：During the initial mining period，the top coal fractures developed rapidly in the roof control area，and their spatial distribution patterns changed periodically with the working face progress；Affected by the fracture development degree，the upper top coal mainly slided in the form of block，while the lower top coal fracture gradually penetrated until broken into loose body.The movement of broken top coal was a combination of vertical and horizontal three-dimensional vector motion.The vertical displacement concentration area of strip loose top coal in goaf behind hydraulic support was the fundamental reason for the occurrence of residual coal.The evolution of the force chain was the fundamental reason of the top coal failure.The method proposed in this study was of great significance to realize 3D automatic multi support complex caving mode simulation，to reveal the mechanism of top coal failure and migration，and to guide the selection of caving support.

Key words:extra-thick coal seam;fully-mechanized top coal caving with large mining height;coupling numerical simulation;dynamic fracture monitoring;progressive failure of top coal

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