Experimental study on the evolution patterns of bursting liability of hard and brittle sandstone under microwave thermal shock

Abstract

Rock burst is a major disaster in deep mining, where bursting liability is an important indicator of rock burst risk. This study therefore intends to explore the impact of microwave thermal shock on rocks with strong bursting liability by testing the microwave thermal shock and uniaxial compression of typical hard brittle sandstone and analyzing their physical and mechanical properties and the response of bursting liability indicators after microwave thermal shock. The research results show that: (1) After microwaving, the surface temperature of the sandstone continues to rise with the increase of thermal shock time, until it breaks at 150 s; (2) Microwave thermal shock has a significant effect on the structural damage of sandstone. After 120 s of microwaving, the longitudinal wave velocity and elastic modulus decrease by 15.12 % and 8 % respectively. The AE signal density increases at each stage of uniaxial compression, and the maximum absolute energy at the final destruction of sandstone decreases by 42.3 %; The dynamic failure time of rock increases by 259 %, the impact energy index decreases by 95 %, and the elastic energy index decreases by 92 %. This research offer references for efficient rock breaking in deep earth engineering and prevention and control of rock burst in resource mining.

Keywords

• rock burst
• microwave
• thermal shock
• bursting liability
• experimental study