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Movement type of the first subordinate key stratum and its influence on strata behavior in the fully mechanized face with large mining height

  • Yunpei Liang
  • Bo Li
  • Quanle ZouEmail author
Original Paper

Abstract

The extraction height of a fully mechanized face with large mining height is large, so the mining-induced overlying strata failure area will be enlarged, which may result in various accidents such as water inrush accidents. In this paper, a combination of theoretical analysis, numerical simulations, and field observations was applied to investigate the movement types of the first subordinate key stratum and its influence on strata behavior in the fully mechanized face with large mining height. The results showed that there were two structural forms and six movement types of the first subordinate key stratum in the fully mechanized face with large mining height. Additionally, conditions favoring the formation of these movement types were presented. The two structural forms of the first subordinate key stratum were the cantilever structure and the stable hinged structure. The cantilever structure of the first subordinate key stratum was located in the caved zone and could present four movement types: direct caving movement of the cantilever structure, double-sided rotation movement of the cantilever structure, quadratic rotation movement of the cantilever structure, and alternative movement of the cantilever structure-hinged structure. The stable hinged structure of the first subordinate key stratum was located in the fractured zone and could present two movement types, namely, voussoir beam structure movement and short voussoir beam structure movement. Additionally, the movement law of each movement type of the first subordinate key stratum and its influence on the strata behavior of the fully mechanized face with large mining height were revealed. Finally, the correctness of the six movement types of the first subordinate key stratum and the corresponding formation conditions were verified using measurement data from four fully mechanized faces with large mining height in China. The outcomes may contribute to reasonable selection of supports and ensuring safe mining of the fully mechanized faces with large mining height.

Keywords

Fully mechanized face with large mining height First subordinate key stratum Cantilever structure Hinged structure 

Abbreviation

FMFLMH

Fully mechanized face with large mining height

SKS 1

The first subordinate key stratum

DCMTCS

Direct caving movement of the cantilever structure

DSRMTCS

Double-sided rotation movement of the cantilever structure

QRMTCS

Duadratic rotation movement of the cantilever structure

AMTCSHS

Alternative movement of the cantilever structure-hinged structure

VBSMT

Voussoir beam structure movement

SVBSMT

Short voussoir beam structure movement

KS

Key stratum

PKS

Primary key stratum

SKS

Subordinate key stratum

CDPW

Continuous distance of the periodic weighting

Notes

Acknowledgments

The authors thank the editor and anonymous reviewers very much for their valuable advices.

Funding information

This work is financially supported by the State Key Research Development Program of China (2016YFC0801404 and 2017YFC0804206), the National Natural Science Foundation of China (51674050 and 51704046), the National Science and Technology Major Project of China (Grant No. 2016ZX05043005), and the Fundamental Research Funds for the Central Universities (106112017CDJXY240001 and 2018CDQYZH0001).

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Copyright information

© Saudi Society for Geosciences 2019

Authors and Affiliations

  1. 1.State Key Laboratory of Coal Mine Disaster Dynamics and ControlChongqing UniversityChongqingChina
  2. 2.College of Resources and Environmental ScienceChongqing UniversityChongqingChina

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