Permeability distribution characteristics of underlying coal seam disturbed by mining activity

ABSTRACT

The permeability distribution law for protected coal seam is the core problem linked to protective coal seam mining. Based on the geological conditions of the Zhongxing coal mine, a numerical protective coal seam mining model was constructed in order to investigate the spatial evolution of stress and the damage characteristics of protected coal seams. During the mining of protective coal seam, the coal body of the protected coal seam undergoes loading followed by three-directional stress unloading. The permeability evolution law of the protected coal seam was derived by combining the relationship between the permeability and axial strain of the coal sample from mechanical-seepage experiments and the swelling and relaxation value of the protected coal seam from numerical simulations. We divided the permeability of the protected coal seam into the original permeability zone, the permeability decreasing zone, the permeability increasing zone, the permeability stable zone, and the permeability re-decreasing zone. The gas drainage data of the protected coal seam during the mining of the protective coal seam were measured in situ. The change laws of the gas drainage volume and gas concentration were essentially consistent with the permeability distribution of the protected coal seam.

KEYWORDS:

• Coal and gas outburst
• protective coal seam mining
• numerical simulation
• permeability distribution
• gas drainage

Additional information

Funding

This research is financially supported by the National Natural Science Foundation of China (Grant No.51874314, 51774292, 51604278, 51804312), the Open Funds of Hebei State Key Laboratory of Mine Disaster Prevention (Grant No. KJZH2017K02), the Yue Qi Distinguished Scholar Project, China University of Mining & Technology, Beijing.

Notes on contributors

Hengyi Jia

Hengyi Jia was born in Xinxiang, Henan, China in 1985. He received the B.S. degree in safety engineering fromHenan Polytechnic University, Jiaozuo, China and received the M.S. degree in safety engineering from China University of Mining and Technology, Xuzhou, China. He is currently pursuing the Ph.D. degree in China University of Mining and Technology (Beijing). His main research direction is the prevention and control of coal and rock gas dynamic disasters, mine safety engineering and mine ventilation.

Kai Wang

Kai Wang received the Ph.D. degree from China University of Mining and Technology, Xuzhou, China in 1997. He was a visiting scholar of the Australian Commonwealth Scientific and Industrial Research Organization from 2005 to 2006. He is currently a Professor with the China University of Mining and Technology, Beijing, China.He holds more than 20 patents and has published more than 150 papers in leading journals and conferences. His current research interests include prevention and control of mine gas, coal rock dynamics disasters and safety and emergency management.

Chao Xu

Chao Xu was born in Taian, Shandong, China in 1988. He received the Ph.D. degree in safety science and engineering from China University of Mining and Technology, Xuzhou, China in 2015. He is an associate professor and the director of Beijing Key Laboratory for Precise Mining of Intergrown Energy and Resources. His current research interests include coal-rock gas dynamic disaster prevention, ventilation and dust removal engineering.

Qiang Fu

Qiang Fu was born in Zhangjiakou, Hebei, China in 1994. He received the B.S. degree in safety engineering from Henan Polytechnic University, Jiaozuo, China. He is currently pursuing the M.S. degree in China University of Mining and Technology (Beijing). His main research direction is coal-rock gas dynamic disaster prevention.