Abstract: In recent years, rockburst induced by excavation of deep underground caverns has become increasingly prominent. Microseismic monitoring technology characterized by micro-fracture location of rock mass has been broadly utilized in rockburst monitoring and early warning of underground engineering. In this paper, a microseismic monitoring system for rockburst monitoring and early warning for the slight rockburst of local surrounding rock during excavation was established and adopted to analyze the microseismic activity in the first two months of the monitoring period. The underground powerhouse area of Huanggou Pumped Storage Power Station was taken as a case study. Results suggest that the frequency of microseismic events is positively correlated with the intensity of blasting excavation. The upstream side arch shoulder and the intersection between lower drainage corridor and workshop installation room are the potential risk areas of rockburst. The research finding offers technical support for the safe construction and stability evaluation of underground caverns.

Key words: rockburst, microseismic monitoring, underground powerhouse, Huanggou Hydropower Station, surrounding rock mass stability