Open Access

ARTICLE

Analysis and Numerical Simulation for Tunnelling Through Coal Seam Assisted by Water Jet

Dengfeng Su¹, Yong Kang^1,2,*, Xiaochuan Wang², andan Zheng¹, DongyangLi¹, Binyuan Yan¹, Fuwen Yan¹

1 State Key Laboratory of Coal Mine Disaster Dynamics and Control, Chongqing University, Chongqing 400030, China
2 Hubei Key Laboratory of Waterjet Theory & New Technology, Wuhan University, Wuhan 430072,China.∗ Corresponding author: Yong Kang. Tel.: + 027-68774906. E-mail address: kangyong@whu.edu.cn

Computer Modeling in Engineering & Sciences 2016, 111(5), 375-393. https://doi.org/10.3970/cmes.2016.111.375

Abstract

Tunnel though coal seam is one of the most difficult tunnels since its risk of coal and gas outburst and the complex geological conditions. According to the directional cutting of water jet and the characteristic of the coal seam and rock mass, this paper presents a new method of tunnelling though coal seam assisted by water jet slotting, which can be divided into improving permeability of coal seam and directional cracking in the rock mass. The mechanism of improving permeability of coal seam was stated, and the crack criterion of rock during blasting was established based on fracture theory. Then, the evolution law of pressure wave and the crack propagation were simulated by FEM software ANSYS/LS-DYNA, the results show that the shape of the crush zone formed by stress wave is different between the normal borehole blasting and the slotted borehole blasting, and the tension is the main factor which let crack propagation. What is more, for normal borehole blasting, the tension concentration occurred along the direction of 45 degrees and let crack expand, while for slotted borehole blasting the tension concentration occurred along the direction of 0 degrees and 90 degrees, and the maximum tension along the direction of 0 degrees is larger than the maximum tension along the direction of 90 degrees, and the main crack expand along the direction of 0 degrees, which prove that the existence of the slot play a good role of orientation for directional cracking.

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