Mechanism and Prevention of Rockburst in Steeply Inclined and Extremely Thick Coal Seams for Fully Mechanized Top-Coal Caving Mining and Under Gob Filling Conditions

Shengquan He, Dazhao Song, Zhenlei Li, Xueqiu He, Jianqiang Chen, Taoping Zhong and Quan Lou
Additional contact information
Shengquan He: School of Civil and Resources Engineering, University of Science & Technology Beijing, Beijing 100083, China
Dazhao Song: School of Civil and Resources Engineering, University of Science & Technology Beijing, Beijing 100083, China
Zhenlei Li: School of Civil and Resources Engineering, University of Science & Technology Beijing, Beijing 100083, China
Xueqiu He: School of Civil and Resources Engineering, University of Science & Technology Beijing, Beijing 100083, China
Jianqiang Chen: Shenhua Xinjiang Energy Company Limited, Urumqi 830027, China
Taoping Zhong: School of Civil and Resources Engineering, University of Science & Technology Beijing, Beijing 100083, China
Quan Lou: School of Municipal and Environmental Engineering, Henan University of Urban Construction, Pingdingshan 467036, China

Energies, 2020, vol. 13, issue 6, 1-26

Abstract: The steeply inclined and extremely thick coal seams (SIETCS) under the condition of gob filling frequently suffer from the occurrence of rockbursts. Figuring out the mechanisms of rockbursts under this condition for taking targeted measures to mitigate rockburst hazards in SIETCS is of great significance. Using the typical SIETCS with an average dip angle of 87° at Wudong Coal Mine (WCM) as a case study, a mechanical model and elastic deformation energy (EDE) function of a “steeply inclined suspended roof structure” was developed, and the influence factors were analyzed by theoretical analysis. Simultaneously, the rockburst risk assessment was carried out based on the theory of a rockburst start-up. The pressure relief measures are optimized by comparing the pressure relief effects of three kinds of destress blasting schemes. The results indicate that the damage characteristics of rockburst are mainly floor heave, the sidewall’s inward deformation and roof subsidence. The damage degree of headentry on the roof side is more severe than that of tailentry, and the resultant impacts showed the directionality from the roof side to the coal side. The steeply inclined and suspended roof breakage is one of the main causes for the occurrence of rockbursts. The EDE of the roof increases with an increasing dip angle of the coal seam from 0° to 72.6° and then decreases as the dip angle increases. Furthermore, that increase is accompanied by the decrease of the lateral pressure coefficient and the supporting force coefficient. The EDE stored in the roof is sufficient to cause roof breakage and induce rockburst after the complete roof exceeds a certain length. The mechanism of rockburst in SIETCS for fully mechanized top-coal caving mining under gob filling conditions was proposed, i.e., “high compressive stress concentration plus breakage of the suspended roof-induced stress” rockburst, and this is further verified by ground destruction, microseismic (MS) monitoring and numerical modeling. The results also indicate that alternate deep and shallow hole-blasting modes are more suitable for pressure relief in SIETCS.

Keywords: rockburst; steeply inclined and extremely thick coal seam; mechanical model; elastic deformation energy; roof breakage; destress blasting (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: 2020
References: View complete reference list from CitEc
Citations: View citations in EconPapers (5)

Downloads: (external link)
https://www.mdpi.com/1996-1073/13/6/1362/pdf (application/pdf)
https://www.mdpi.com/1996-1073/13/6/1362/ (text/html)

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:gam:jeners:v:13:y:2020:i:6:p:1362-:d:332775

Access Statistics for this article

Energies is currently edited by Ms. Agatha Cao

More articles in Energies from MDPI
Bibliographic data for series maintained by MDPI Indexing Manager ().