›› 2018, Vol. 39 ›› Issue (4): 1411-1421.doi: 10.16285/j.rsm.2017.0168

• Geotechnical Engineering • Previous Articles     Next Articles

Mechanism of advance fracture of main roof and its control technology when workface crossing abandoned roadway

LIU Chang1, 2, ZHANG Jun-wen1, YANG Zeng-qiang1, GONG Pei-lin2, WANG Kai2, ZHANG Xiao-qiang2, LI Yu-lin3   

  1. 1. College of Resources and Safety Engineering, China University of Mining and Technology (Beijing), Beijing 100083, China; 2. College of Mining Engineering, Taiyuan University of Technology, Taiyuan, Shanxi 030024, China; 3. Institute of Mining Engineering, Heilongjiang University of Science and Technology, Harbin, Heilongjiang 150022, China
  • Received:2017-02-07 Online:2018-04-11 Published:2018-06-06
  • Supported by:

    This work was supported by the National Key Research and Development Program (2016YFC0600901), the Program of the Twelfth Five-year Plan for Science and Technology Research of China (2012BAB13B04), the National Natural Science Foundation of China (51574114, 51674263) and the State Key Research and Development Program of China (2016YFC0801403).

Abstract: Similar simulation experiments were carried out to study the chock sudden closure incident of hydraulic supports when the workface crossed the abandoned roadway or accessed to the removal roadway. The failure characteristics of surrounding rock, the abutment pressure and the working resistance of supports were investigated through the experiments, respectively. Results indicate that the advance fracture appeares before the incident when the workface crosses a large section roadway. The advance fracture leads to an increase of the block length, comparing to that in a normal periodic weighting. Meanwhile, the inferior key stratum brokes and then slides down to the main roof. Once the advance fracture occurrs, conventional supports are unable to prevent the block sliding, which indicates that an incident takes place. Therefore, the most important thing is to prevent the occurrence of advance fracture. To investigate the main causes for the advance fracture, bending moment and deflection of the main roof are calculated by the Winkler foundation beam theory. The calculated results comprehensively explain the failure characteristics of surrounding rock, the abutment pressure and the working resistance of supports. Finally, it is revealed that the failure of coal pillar is the reason for advance fracture of the main roof. Hence, it is significant to improve the strength of coal pillar. At last, a roadway filling strategy is put forward to make uniaxial compression of coal pillar into triaxial compression by Shenghua coal mine. In-situ tests verifies that the strength of coal pillar is successfully increased.

Key words: crossing abandoned roadway, similar simulation, advance fracture, failure of coal pillar

CLC Number: 

  • TU 457

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