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ORIGINAL RESEARCH article

Front. Earth Sci.
Sec. Geohazards and Georisks
Volume 12 - 2024 | doi: 10.3389/feart.2024.1430018
This article is part of the Research Topic Risk Assessment, Stability Monitoring, and Safe Design for Deep Rock Engineering View all 20 articles

A selection methodology on reasonable width of stabilized coal pillar for retracement channel in longwall working face

Provisionally accepted
Pengfei Shan Pengfei Shan Zheng Meng Zheng Meng *Xingping Lai Xingping Lai Xiongfei Xue Xiongfei Xue Chenwei Li Chenwei Li Jindong Wang Jindong Wang Wei Li Wei Li Long Zhang Long Zhang Bojia Xi Bojia Xi Hongjun Jiang Hongjun Jiang
  • Xi'an University of Science and Technology, Xi'an, China

The final, formatted version of the article will be published soon.

    In this paper, the No.30201 working face of a specific colliery was determined as the study area in the Yushen mining area, China. The objective of this paper is to determine the optimal position for pressure regulation measures during the final mining stage. A mechanical calculation model for stabilized coal pillar was developed. The analytical solution for the front abutment pressure function was obtained. Limit equilibrium theory and beam theory were employed to compute the critical width value of the stabilized coal pillar. The analysis focused on examining the spatiotemporal relationship between the rotational deformation of the main roof and the stability of the retracement channel. The study utilized numerical simulation to investigate the failure characteristics of the surrounding rock and the stress redistribution in the stabilized coal pillar within the working face. Through comprehensive analysis, a reasonable width of 15 meters for the stabilized coal pillar was determined and successfully implemented in field practices. A method of using Artificial Neural Network (ANN) to select the stabilized coal pillar width was proposed. The input characteristics of ANN were determined through theoretical analysis. Four models of BP, WOA-BP, PSO-BP, and CPSO-BP were trained. The calculation accuracy of each model is evaluated by three quantitative metrics: MAE, MRE, and RMSE. The MAE value of the CPSO-BP model is 0.9489, showing a reduction of 70.87% compared to the BP model, 55.84% compared to the WOA-BP model, and 51.26% compared to the PSO-BP model. The MRE value is 0.0559, which is 71.51 %, 56.29 %, and 53.24 % lower than the other models, respectively. The RMSE value is 1.0617, which is 68.92 %, 56.13 %, and 53.03 % lower than other models, respectively. The four models were employed to compute the width of the stabilized coal pillar. The values for the BP, WOA-BP, PSO-BP, and CPSO-BP models were 12.7 meters, 16.3 meters, 14.1 meters, and 15.2 meters, respectively, indicating that the CPSO-BP model can effectively determine the width of the stabilized coal pillar.

    Keywords: Retracement channel, Coal pillar, stability analysis, numerical simulation, Neural Network

    Received: 09 May 2024; Accepted: 10 Jul 2024.

    Copyright: © 2024 Shan, Meng, Lai, Xue, Li, Wang, Li, Zhang, Xi and Jiang. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

    * Correspondence: Zheng Meng, Xi'an University of Science and Technology, Xi'an, China

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