Assessment of the feasibility of detecting cracks in the Sayano-Shushenskaya HPP dam based on a detailed analysis of its natural frequencies

This paper explores the potential for diagnosing the structural integrity of large hydraulic structures, such as the Sayano-Shushenskaya HPP (SSHPP), through the analysis of changes in their natural frequencies. It describes how seismographs located away from the object under study can be used to record microseismic vibrations and convert them into spectrograms. Using data collected between 2016 and 2024, it analyses the dependence of the fourth mode frequency of dam vibrations on the fill level and ambient temperature of the dam. The analysis shows that the fill level significantly affects the natural frequency of the dam, while the effect of temperature demonstrates ambiguous dependencies that require further study. The paper demonstrates that abnormal changes in the natural frequency of the dam occur at the limit values of the reservoir filling, which can be associated with defects revealed when significant hydrostatic pressure arises. Graphs comparing the frequency with deformation graphs obtained directly on the dam are provided. The importance of taking into account various factors that may influence changes in natural frequencies is emphasized. The method under consideration has shown good potential and should be tested on several structures in future.