Numerical simulation of rock-burst relief and prevention by water-jet cutting

• The mechanism of rockburst relief and prevention using WJCT is analyzed.
• Horizontal radial slots will produce “beam structure” and “small pillar skeleton”.
• Annular vertical slots will generate “layered energy reservoir structure”.
• The slots׳ positions and their combination are reasonably designed and optimized.
• Rockburst relief and prevention effect were verified using EMR method.

The applications in coal mine rock burst prevention using water jet cutting technology (WJCT) have progressed slowly. In this paper we analyzed the possibility and reasonableness of WJCT application to rock burst relief and prevention, used the ABAQUS software to simulate the distributive characteristics of stress and energy fields suffered by hard coal roadway wallrock and the internal relationships of the fields to the instability due to WJC on roadway wallrock, and conducted field WJCT tests using electromagnetic radiation (EMR) measurement technology. The results showed that WJCT can unload rock burst effectively by inducing stress release and energy dissipation in coal mass near its cut slots; its annular slots also can decrease rock burst risks through blocking or weakening stress and energy transfer in coal mass. The horizontal radial slots and annular vertical slots may cause “the beam structure” and “the small pillar skeleton”, and “the layered energy reservoir structure”, respectively, which lead to an increase in stress concentration and energy accumulation in coal element mass near the slots. The reasonable design and optimization of slots׳ positions and their combination not only can significantly reduce the scope of stress concentration and energy accumulation, but also can destroy coal mass structure on a larger scale to force stress to transfer deeper coal mass, eventually avoiding high intensity and large-scale rock bursts. The field tests of WJC for pressure relief using EMR verified the above conclusions.