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A caving self-stabilization bearing structure of advancing cutting roof for gob-side entry retaining with hard roof stratum

  • Yang, Hongyun (State Key Laboratory of Mountain Bridge and Tunnel Engineering, Chongqing Jiaotong University) ;
  • Liu, Yanbao (China Coal Technology Engineering Group Chongqing Research Institute) ;
  • Cao, Shugang (State Key Laboratory of Coal Mine Disaster Dynamics and Control, Chongqing University) ;
  • Pan, Ruikai (State Key Laboratory of Coal Mine Disaster Dynamics and Control, Chongqing University) ;
  • Wang, Hui (State Key Laboratory of Coal Mine Disaster Dynamics and Control, Chongqing University) ;
  • Li, Yong (State Key Laboratory of Coal Mine Disaster Dynamics and Control, Chongqing University) ;
  • Luo, Feng (School of Mining and Geomatics, Hebei University of Engineering)
  • Received : 2019.12.09
  • Accepted : 2020.03.04
  • Published : 2020.04.10

Abstract

An advancing cutting roof for gob-side entry retaining with no-pillar mining under specific geological conditions is more conducive to the safe and efficient production in a coalmine. This method is being promoted for use in a large number of coalmines because it has many advantages compared to the retaining method with an artificial filling wall as the gateway side filling body. In order to observe the inner structure of the gateway cutting roof and understand its stability mechanism, an equivalent material simulation experiment for a coalmine with complex geological conditions was carried out in this study. The results show that a "self-stabilization bearing structure" equilibrium model was found after the cutting roof caving when the cut line deviation angle was unequal to zero and the cut height was greater than the mining height, and the caving roof rock was hard without damage. The model showed that its stability was mainly controlled by two key blocks. Furthermore, in order to determine the optimal parameters of the cut height and the cut line deviation angle for the cutting roof of the retaining gateway, an in-depth analysis with theoretical mechanics and mine rock mechanics of the model was performed, and the relationship between the roof balance control force and the cut height and cut line deviation angle was solved. It was found that the selection of the values of the cut height and the cut line deviation angle had to conform to a certain principle that it should not only utilize the support force provided by the coal wall and the contact surface of the two key blocks but also prevent the failure of the coal wall and the contact surface.

Keywords

Acknowledgement

Supported by : National Natural Science Foundation, Chongqing Municipal Education Commission

The authors gratefully acknowledge funding by National Natural Science Foundation Project of China (51904043, 51804093, 51774059, 51804058), and Basic Research of Frontier and Application of Chongqing (cstc2015jcyjA90019, cstc2016jcyjA0085), Chongqing Technological Innovation and Application Demonstration Project (cstc2018jscx-msybX0067), Science and Technology Research Program of Chongqing Municipal Education Commission (KJQN201800729).

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