Security risk assessment of rockburst in the process of tunnel excavation by drilling and blasting method in deep-buried hard rock

摘要

Based on the background of deep-buried tunnels project in Jinping Ⅱ hydropower station,focusing on the prominent problems,such as casualties,equipment and facility damage caused by rockburst hazard,this paper attempts to provide a security risk assessment methodology during deep-buried tunnel excavation by drilling and blasting method.The results of previous research regarding the prediction of rockburst by means of real-time microseismic monitoring technique,in combination with the relevant statistical data from a large number ofrockburst samples,have been used to propose the implementation procedures of dynamic risk assessment ofrockburst during tunnel construction,which involves identifying and dividing risk region,analyzing the probability of risk,estimating the consequences of risk,determining the level of risk,evaluating and controlling the risk.Finally,one case study is given of the use of this method in the process of tunnel construction.