A Study Of Structural Damage Detection Based On The Dam’s Monitoring Information Of Strong Earthquake Response

At present,a lot of dams have been constructed in quake-prone regions in the southwest of China with the reservoir capacity of billions of or even tens of billions of cubic meters,and incalculable consequences will be brought if the damage appears,so it is of great significance to conduct the damage identification during service period.In this paper,based on the wavelet analysis and data statistical analysis,the damage identification is conducted.Through the experimental study on damage of concrete gravity dam shaking table dynamic model,the damage process of the concrete gravity dam under the earthquake is analyzed.Combined with numerical calculation,the dam damage time,location and degree are studied.The main contents are as follows:(1)The concrete dam will undergo the development process from linear elasticity to nonlinear elasticity under strong earthquakes,resulting in changes in structural dynamics characteristics,in which the response information can be recorded by a variety of monitoring instrument on the dam.Because the wavelet transform is not sensitive to the singularity point and it is easy to misjudge,the damage early-warning index sk based on wavelet transform is proposed.(2)The linear elastic model is adopted to simulate the position damage of the concrete gravity dam,with the dam body elasticity moduli reduction(E)to simulate the structural stiffness reduction for reflecting structural damages at different degrees.And the correlation between the wavelet transform and the acceleration response is used to analyze the structural response and identify the location and extent of damage to the structure.The damage of the single position and multiple positions are studied by using the correlation of acceleration response,which is verified to have a certain noise – resistance ability.(3)The model of the gravity dam is cast by simulated concrete,and the dynamic model damage experiment is conducted on the large vibrating table to investigate the damage process of the concrete gravity dam in different earthquakes.In addition,the whole dam damage under different peak ground acceleration(PGA)is discussed in this paper;the empirical mode decomposition method is used for studying the denoising of experimental signals,showing that the empirical mode decomposition method with no need for selecting the basis function is equally effective for the denoising of experimental signals;and the wavelet transform is used to analyze whether a position is damaged in the structure.