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Failure Mechanism and Deformation Characteristics of Gob-Side Entry Retaining in Solid Backfill Mining: A Case Study

  • Qiang SunEmail author
  • Jixiong Zhang
  • Yanli Huang
  • Wei Yin
Original Paper
  • 58 Downloads

Abstract

In solid backfilling mining, gangue and other solid materials are backfilled into the gob to restrain the roof subsidence. As a result, instead of being subjected to periodic collapse, the overlying strata will be able to maintain its integrity and bend or sink as a whole with partial fracture and failure, thus facilitating the gob-side entry to retain. To study the mechanical deformation characteristics and failure mechanism of such gob-side supporting wall, this research analyzes the structure features of the surrounding rock in gob-side entry and builds mechanical damage model for gob-side supporting based on the hypothesis of planar slip surface in the theory of Coulomb earth pressure. The relationship among normal force acting on the contact face N, the angle between the slip surface of gangue and vertical face η and other relevant factors are discussed. The result suggests that η is mainly affected by δ, the friction angle between the backfill body and the supporting wall interface, and φ, the internal friction angle of backfill materials; η increases as δ increases and decreases as φ increases. N, mainly affected by δ, φ and uniformly distributed load q, has positive correlation with q and negative correlation with δ and φ. The research also reveals that compressive stress exists only when the width of wall exceeds 1.741 m; such stress will decrease sharply when the width of wall is between 2 m and 3 m, and become stable when the width goes beyond 3 m. According to numerical simulation and field test, the maximum values of roof-to-floor longitudinal deformation and lateral deformation between two sidewalls are 350 mm and 210 mm, respectively. The research results proved that the model employed can accurately predict and evaluate the deformation and damage of the gob-side entry.

Keywords

Gob-side entry retaining Backfill mining technology Deformation mechanism Fracture and failure Gob-side supporting wall 

Notes

Acknowledgments

This work is supported by the National Key R&D Program of China (2018YFC0604705), the National Science Fund for Distinguished Young Scholars (51725403), and the Natural Science Foundation of Colleges in Jiangsu Province (KJB440004). The authors gratefully acknowledge the financial support of the above-mentioned organizations.

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Copyright information

© International Association for Mathematical Geosciences 2019

Authors and Affiliations

  • Qiang Sun
    • 1
    • 2
    Email author
  • Jixiong Zhang
    • 1
  • Yanli Huang
    • 1
  • Wei Yin
    • 3
  1. 1.State Key Laboratory of Coal Resources and Safe Mining, School of MinesChina University of Mining and TechnologyXuzhouChina
  2. 2.State Key Laboratory for Geomechanics and Deep Underground EngineeringChina University of Mining and TechnologyXuzhouChina
  3. 3.Faculty of Transportation EngineeringHuaiyin Institute of TechnologyHuaianChina

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