Analysis of ground vibration propagation problems induced by high dam flood discharge using finite-infinite element coupled method

Abstract: When flood is discharged from a high dam, vibrations are generated due to huge flood fluctuating load and transmitted to the surrounding ground to cause ground vibrations harmful to adjacent structures and residents' normal life. Here, by introducing the finite-infinite element theory, a finite-infinite element coupled model containing discharge structures, foundation and surrounding ground body was established. With this model, the multi-vibration sources excitation simulation method was studied to analyze ground vibration propagation problems induced by high dam flood discharge. The results showed that if five excitation sources collected simultaneously are taken as five independent and uncorrelated equivalent loads and boundary conditions are treated with the infinite element, the calculation results are closer to the original measured results; the ground vibration intensity in an old channel region is relatively larger, it intensity change is not big in the initial stage of vibration propagation along a horizontal plane but the intensity decays quickly in the later stage; the vibration intensity of other regions is smaller, the vibration decays quickly but it becomes slow with increase in distance; the vibration energy in the early stage is a broadband vibration within a range of 0.5-4.0 Hz, along with the vibration propagating to the downstream, the vibration energy band becomes more concentrated and the vibration energy with lower frequency decays rapidly; in the vertical propagation process, the vibration intensity of cover layer fluctuates in the same order of magnitude, and the vibration frequency band is wider; when the vibration transmits to a shallow mudstone foundation, its intensity decreases rapidly, its frequency band becomes narrow and the lower frequency vibration part is gradually filtered by soil; when the vibration transmits to a deep sandstone foundation, the vibration intensity can be neglected. © 2018, Editorial Office of Journal of Vibration and Shock. All right reserved.