Research on Vibration Characteristics of an Underground Powerhouse of Large Pumped-Storage Power Station

Abstract

With the rapid development of pumped storage, the vibration problems caused by the operation of power stations have become increasingly prominent. In this paper, a large-scale pumped-storage power station is taken as the research object, and a three-dimensional refined finite element model of the underground powerhouse including the surrounding rock mass is established. Based on the analysis of the vibration source of the powerhouse and the water diversion pipeline, the modal and dynamic response analysis of the underground powerhouse of the hydropower station is carried out, and the distribution law of the larger vibration displacement position is revealed. The calculation results show that under the premise that the vibration source is selected reasonably and the numerical model is accurate, the main frequency of the underground powerhouse structure can be obtained more accurately. After optimizing the design of the underground powerhouse based on the calculation results, the resonance problem of the underground powerhouse of the hydropower station can be avoided. The dynamic elastic modulus of the rock mass around the underground powerhouse has little influence on the mode shape of the powerhouse, but has a great influence on its fundamental frequency. When the dynamic elastic modulus of the rock mass increases by 50%, the fundamental frequency of the plant increases by about 29%. At the same time, the mode shape of each order of the underground powerhouse structure does not change much, mainly manifested as the vibration of the beam system structure, which is mainly caused by the stiffness of the beam system components being much smaller than the structural stiffness of the windshield, machine pier, and mass concrete around the volute. The research results can provide references for the design of underground powerhouses of large-scale pumped-storage power stations and the analysis of vibration problems.