Numerical simulation study on liquid CO2 phase transition blasting under the action of in-situ stress

WANG Yan

doi:10.13347/j.cnki.mkaq.20240034

Abstract：In order to clarify the mechanical properties and failure mechanism of coal(rock)under high ground stress conditions,a theoretical model was used to analyze the stress field distribution under the coupling effect of ground stress and CO2 phase change blasting impact load,and the influence mechanism of ground stress on CO2 phase change blasting crack propagation was revealed;the impact load was applied to coal(rock)to simulate the CO2 phase change blasting process,and the effects of ground stress mag-nitude and lateral stress coefficient on the distribution of hoop stress,radial stress field were analyzed.The research results indicate that under equal biaxial pressure conditions,circular compressive stress is generated at the borehole wall;as the ground stress in-creases,the hoop stress also increases,and the hoop stress is twice that of the in-situ ground stress;the hoop compressive stress hinders the initiation and propagation of radial cracks in all directions;the in-situ stress causes stress concentration near the hole wall,and the hoop stress has a larger value compared to radial stress,and the effect of in-stress causes the hoop stress field to play a decis-ive role in the propagation of cracks,therefore,most cracks will develop radially;the hoop stress exhibits oscillatory attenuation characteristics with increasing time and eventually stabilizes around the initial ground stress.