Abstract: Taking a hydropower station as the engineering background,three-dimensional numerical analysis model is established based on autocad and FLAC^3D-Extruder geological modeling software,three-dimensional numerical simulation analysis of cavern excavation and whole process of large volume concrete smooth pouring of underground powerhouse is done,so as to study the variation characteristics of stress,strain and plastic zone of cavern surrounding rock,and the mechanical characteristics of bolt and shotcrete layer structure during the process of cavern excavation and large volume concrete smooth pouring of underground powerhouse.The study results show that:any abnormal situations are not appeared during the construction process by using stage excavation method,the stability of cavern surrounding rock is good,the anchor and shotcrete stress state are reasonable with the support of shotcrete,which further indicated that the excavation method and parameters of bolting and shotcrete support are feasible.The above study results in this paper can provide some technical reference for engineering management,excavation supporting and monitoring design.

Key words: FLAC^3D, Underground powerhouse, Concrete pouring, Numerical simulation