Law of coal caving behind the flexible shield support in pseudo-inclined working face

PLoS One. 2021 Dec 30;16(12):e0261355. doi: 10.1371/journal.pone.0261355. eCollection 2021.

Abstract

Complex boundary conditions are the major influencing factors of coal caving law in the pseudo-inclined working face. The main purpose of this study is to analyze coal caving law of flexible shield support and then to establish the internal relations among coal caving parameters under complex boundary conditions. Firstly, the law of coal caving in different falling modes is simulated physically. Secondly, the coal caving shape, displacement field, and contact force field is simulated. Then, coal caving law and process parameters is analyzed theoretically. Finally, the test was performed in Bai-Ji Mine. The research shows that ellipsoidal ore drawing theory has universal applicability in coal drawing law analysis and parameter optimization. After the Isolated Extraction Zone and Isolated Movement Zone reach the roof, the expansion speed is marked by a short delay, and then, while expanding to the floor, two butted incomplete ellipsoids are formed. There is a time-space difference in coal caving after the support, and some coal will be mined in the next round of coal caving. There are obvious differences in the coal loosening range, displacement field, and contact force field on both sides of the long axis. When the support falls along with the bottom plate, it is more conducive to the release of coal. The test shows that the research is of great significance for optimizing the caving parameters of flexible shield support in the pseudo-inclined working face of the steep seam.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Caves
  • China
  • Coal Mining / instrumentation*
  • Coal Mining / methods*
  • Coal*
  • Computer Simulation
  • Models, Theoretical
  • Normal Distribution
  • Reproducibility of Results

Substances

  • Coal

Grants and funding

1) The research was funded by the National Natural Science Foundation of Guangdong (2018A0303130162), URL of the funder website: http://gdstc.gd.gov.cn/. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Dr. Qinjian Zhan 2) The research was funded by the national natural science foundation of china (51574226), URL of the funder website: https://www.nsfc.gov.cn/. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Dr. Niaz Muhammad Shahani 3) The research was funded by the 2017 special project of subject frontiers scientific research in china university of mining and technology (2017XKQY047), URL of the funder website: http://www.cumt.edu.cn/. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Dr. Niaz Muhammad Shahani.