Control Technology of Soft Rock Floor in Mining Roadway with Coal Pillar Protection: A case study

Housheng Jia, Luyao Wang, Kai Fan, Bo Peng and Kun Pan
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Housheng Jia: School of Energy Science and Engineering, Henan Polytechnic University, Jiaozuo 454000, China
Luyao Wang: School of Energy Science and Engineering, Henan Polytechnic University, Jiaozuo 454000, China
Kai Fan: Technology Center of Sichuan Province Coal Industry Group, Chengdu 610091, China
Bo Peng: Sichuan Hua Ying Shan Longtan Coal and Electricity Co., LTD., Guangan 638020, China
Kun Pan: School of Energy Science and Engineering, Henan Polytechnic University, Jiaozuo 454000, China

Energies, 2019, vol. 12, issue 15, 1-21

Abstract: This study considered the mining roadway with coal pillar protection in the fully mechanized caving face of the Dananhu No.1 Coal Mine, China. Theoretical analysis, numerical simulation, and field tests were conducted, and the stress environment, deformation, and failure characteristics of the mining roadway in the fully mechanized caving face were analyzed. The results revealed that the intrinsic cause for the large asymmetrical floor deformation in the mining roadway is the asymmetrical phenomenon of the surrounding rock’s stress environment, caused by mining. This also results in the non-uniform distribution of the mining roadway floor’s plastic zone. The degree of asymmetrical floor heave is internally related to the thickness of the caving coal. When the thickness of the caving coal was in the range of 5.9 m, the deformation of the asymmetrical floor heave, caused by the plastic failure in the floor, became more obvious as certain parameters increased. As the rotation angle of the principal stress direction increased, the maximum plastic failure depth position of the floor gradually moved toward the middle of the roadway. This caused a different distribution for the maximum deformation position. The control of the floor heave deformation was poor, and it was not feasible to use high-strength support under the existing engineering conditions. Hence, the control should mainly be applied to the floor heave deformation. When the thickness of the caving coal was more than 5.9 m, the main roof strata was prone to instability and being cut along the edge of the coal pillar; the rock stress environment surrounding the roadway tended to revert back to the initial geostress state. The proposed floor heave control strategy achieved good results, and as the deformation of the floor heave decreased, the workload of the floor heave was also greatly reduced.

Keywords: mining roadway; coal pillar protection; soft rock floor; large deformation; plastic zone (search for similar items in EconPapers)
JEL-codes: Q Q0 Q4 Q40 Q41 Q42 Q43 Q47 Q48 Q49 (search for similar items in EconPapers)
Date: 2019
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (2)

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