Monitoring is one of the important bases for dynamic design and information construction in underground project

and the analysis and reporting of monitoring information are even more important

if they are all-sided

accuracy and timely. The excavation of underground powerhouse of Pengshui project in Wujiang River faces many problems

such as large-scale span and height

complex geological conditions

long period

the disturbance of construction

etc. In order to ensure safety of construction and operation

many monitoring instruments were installed in underground powerhouse

which were used to monitor the deformation and stability of surrounding rockmass in construction. The analysis of monitoring results indicate: the surrounding rockmass of underground powerhouse is stable in general; design supports can enhance the self-stability of rockmass and ensure the stability of underground powerhouse; however

the stability of some local rock masses

especially the shale in the downstream sidewall are bad due to geological condition and rockmass blasting.