Stability Analysis and Fracture Mechanism of Surrounding Rock in a Hydraulic Tunnel Based on Microseismic Monitoring

Numerous large hydropower projects have been built, are being built, or are planned to be developed in southwest China as a result of the increasing demand for clean energy in China's social and economic development. Based on engineering geological data, site surveys, and the temporal and spatial distribution characteristics of microseismic (MS) events, an MS monitoring system was developed in this study to analyze the stability of the surrounding rock of the spillway tunnel of the Jinchuan hydropower station as well as the fracture and damage mechanism in the concentration zone. The results of the study indicated that the distribution of MS events was correlated with the construction process and geological conditions, that the concentration of MS events and their great moment magnitude could be regarded as signs of future damage to the surrounding rock, and that the surrounding rock of the spillway tunnel primarily exhibited non-shear failure, such as tensile failure, with only a small area exhibiting shear failure. The results can be used as a construction reference and as a forewarning of surrounding rock deformation.

Automated summary

A microseismic monitoring system was developed in this study to analyze the stability of the surrounding rock of a spillway tunnel in a hydropower station. The results indicated that the distribution and magnitude of microseismic events can serve as signs of future damage to the rock.