Vibration Characteristics And Monitoring Method Analysis Of Hydroelectric Power Plant On Thick Overburden Layer

With the development of China's hydropower construction,the construction of station has begun to transfer to the rich areas of water energy resources in the Midwest.The geological conditions of these areas are complex,and the bed foundations are mostly deep cover layers,as a soft base foundation,the deep cover layers foundations have obvious nonlinear characteristics,so it is bound to have an impact on the vibration characteristics of the civil structure.Considering the nonlinear characteristics of the soil and the structural characteristics of the station on the deep overburden,in this paper,the finite element method is applied to analyze the vibration characteristics and vibration monitoring of the powerhouses and its foundations.Considering the nonlinear damping characteristics of the soil,based on the finite element method,using different boundary conditions and damping parameter value method,established the finite element dynamic model of deep overburden layers,it can be found by comparing the results achieved by the present method and the traditional frequency domain equivalent linear method that:The dynamic model that applied viscoelastic boundary and Zou Degao damping computational method can respond well to the vibration characteristics of the deep layer.On the basis of the above,the whole model of thick overburden layer foundation hydropower plant can reflect the dynamic characteristics on the foundation of the soft foundation.Comparison of the model of hydropower plant with the fixed boundary condition of the foundation without thick overburden layer:Thick overburden layer foundation can expand the range of the natural frequency of plant,and it also raised the inherent vibration frequency and the frequency of the vibration source of the hydropower plant,the damping of soil in the thick overburden layer can play a role in dissipating the vibration energy,this avoids the structural resonance of the power plant and the vibration source of the hydropower station to a certain extent.Aiming at the limitation of mesh generation in finite element method,A method to determine the optimal location of the monitoring sensor is put forward by combining the minimum error criterion of recognition error and the interpolation fitting criterion.This method avoids the problem of losing the optimal solution only when using the least error minimum criterion method.Through an example,the optimal arrangement of sensors for a hydropower plant on the thick overburden layer is analyzed,and the calculation process of the method is demonstrated.