Research On Response Of Concrete Rock Face Beam To Stage Excavation Blasting Vibration In Underground Powerhouse

The rock face beam is a new structure model. The pouring of the rock face beam concrete has been finished and the rock face beam is justly located at the upper side of the excavation blasting working plane during the excavation of the lower layer. The safety and stability of the rock face beam have been being an important problem in blasting engineering.In this paper, based on the safety monitoring of stage excavation blasting in the Tai' an pumped storage power station project, the subject investigated is the rock face beam. Through the field test of blasting seismic vibration, the velocity oscillogram of the points on the top face and the maximum vibration velocity are obtained. On the base of the theory of transmission of blasting seismic wave the parameter value K, α in the empirical equation are defined according to regression analysis of the field data. Thus the velocity attenuation law of excavation blasting seismic wave is got. Then according to the theory of wavelet analysis, the field data analyzed by the use of wavelet packet analysis through Matlab- programming. The character of frequency- spectrum and energy of stage excavation blasting seismic waves of underground powerhouse in the Tai' an pumped storage power station project is concluded. Energy distribution of seismic wave at various frequency bands is analyzed. Therefore frequency band where energy is concentrated relatively and main vibrating frequency are gained.Vibration of the concrete rock face beam in underground powerhouse caused by stage excavation blasting is numerical simulated through the 3-Dimensional explicit finite difference program FLAC-3D in the Tai' an pumped storage power station. The law of the change of distribution of stress and displacement in surrounding rock and rock face beam during the course of stage excavation blasting in underground powerhouse is analysed. And also vibration velocity curves of the key points are obtained. Thus dynamic response of the rock face beam under blasting seismic wave is researched. Compared with the in-situ results, computing...