Study on Influence of Advanced Stress Release Parameters in Deep-buried Tunnels

The release of advanced stress by pressure relief blasting can control strong rock burst quickly, safely and effectively. The synergistic action of blasting parameters is calculated by orthogonal test method, and the results are analyzed by the difference analysis and the SPSS linear regression analysis. The analysis results show that the uncoupling coefficient K has the largest influence on the blasting unloading effect, followed by the hole diameter D, the borehole spacing L, the millisecond difference time t has the least influence; in the extreme difference analysis, the optimum range of the blasting parameters is obtained. In SPSS analysis, the linear regression equation between the particle vibration velocity and the blasting unloading parameters of the borehole wall is obtained. Aiming at a deep-buried tunnel in Tibet, the best parameters of blasting are obtained by analysis, and the blasting scheme of tunnel unloading is drawn up, and the FLAC^3D dynamic simulation analysis is carried out. The results show that the stress size and distribution range are greatly reduced before unloading, and the stress concentration area is transferred to the deep part of the rock mass, which proves the rationality of the drilling hole parameters and the effectiveness of pressure relief blasting to prevent rock burst.