Crack Damage Propagation and Morphology Distribution of Hydraulic Electric Pulse Fractured Coal

Xiankai Bao; Wu Zhang; Shuang Zhao; Ning Wu; Chaoyun Yu; Jinchang Zhao; Wenxiang Zheng

doi:10.1021/acsomega.2c08178

Crack Damage Propagation and Morphology Distribution of Hydraulic Electric Pulse Fractured Coal

ACS Omega. 2023 Apr 21;8(18):16032-16046. doi: 10.1021/acsomega.2c08178. eCollection 2023 May 9.

Authors

Xiankai Bao^{1

2

3}, Wu Zhang¹, Shuang Zhao¹, Ning Wu¹, Chaoyun Yu¹, Jinchang Zhao⁴, Wenxiang Zheng⁵

Affiliations

¹ School of Civil Engineering, Inner Mongolia University of Science and Technology, Baotou 014010, China.
² Inner Mongolia Autonomous Region Building Structure Disaster Prevention and Mitigation Engineering Technology Research Center, Inner Mongolia University of Science and Technology, Baotou 014010, China.
³ Inner Mongolia Autonomous Region Key Laboratory of Civil Engineering Safety and Durability, Inner Mongolia University of Science and Technology, Baotou 014010, China.
⁴ School of Mining Engineering, Taiyuan University of Technology, Taiyuan 030024, China.
⁵ School of Mining and Coal, Inner Mongolia University of Science and Technology, Baotou 014010, China.

Abstract

This work discusses the damage and failure effect of a hydraulic electric pulse and the law of crack growth on coal. The impact and failure effect of a water shock wave and the mechanism of crack initiation, propagation, and arrest were studied by numerical simulation and the fracturing test of coal, combined with CT scanning, PCAS software, and Mimics 3D reconstruction technology. The results show that a high voltage electric pulse that increases permeability is an effective artificial crack making technology. The crack spreads radially along the borehole, and the damage degree, number, and complexity were positively correlated with the discharge voltage and discharge times. The crack area, volume, damage factor, and other parameters increased steadily. The cracks in the coal first start from two symmetrical angles, and finally distribute in a 360 deg circumferential direction, forming a multiangle crack spatial network structure. The fractal dimension of the crack group increases, the number of microcracks and the roughness of the crack group increases, the overall fractal dimension of the specimen decreases, and the roughness between cracks weakens. The cracks then form a smooth coal-bed methane migration channel. The research results can provide some theoretical guidance for the evaluation of crack damage propagation and the effect of electric pulse fracturing in water.