Analysis of structural vibration characteristics of embankment dam based on DVMD–VDR

Aiming at the problem that earth-rock dam structure is susceptible to non-stationary signal interference in the process of collecting vibration information, this paper proposes a feature information extraction method based on the fusion of Dispersion Entropy Variational Mode Decomposition (DVMD) and Variance Dedication Rate (VDR) improved by Dispersion Entropy. First, multi-channel vibration signals are dynamically fused using the variance dedication rate to extract the complete vibration information of the dam body; then the entropy value of each modal component (Intrinsic Mode Function) under different decomposition layers is calculated by using Dispersion Entropy, and the entropy turning point is selected to determine the number of decomposition modes of DVMD, to compensate for the insufficiency of blind selection of decomposition modes in Variational Mode Decomposition. The entropy value turning point is selected to determine the number of decomposition modes of DVMD, which can make up for the deficiency of blindly selecting decomposition modes in Variational Mode Decomposition. To verify the accuracy and effectiveness of the method in this paper, three groups of simulated signals are constructed for numerical simulation, and it is found that its noise reduction effect is better than that of digital filtering, wavelet thresholding and Improved Variational Mode Decomposition, and the signal feature information can be effectively extracted. Combining the measured data of the embankment dam of HeLong dam site under the excitation of natural environment, the operational characteristic information of the dam body is analyzed and compared with the finite element simulation results, and the study shows that the DVMD–VDR method can efficiently extract the complete vibration characteristic information of the structure, which has a good engineering practicability, and it can provide the basis for the on-line monitoring of the structural operational status of the embankment dam.