Scientists from Novosibirsk State Technical University (NSTU) and the Institute of Petroleum Geology and Geophysics SB RAS named after A. A. Trofimuk has developed a unique comprehensive methodology for examining hydroelectric dams. The technique allows for the inspection of dams for defects, without adversely affecting the hydraulic structure and without requiring the shutdown of the hydroelectric power plant.
Dam inspection is primarily a safety issue. Hydraulic structures are subject to various factors that can lead to deterioration of their condition over time. As noted by Alina Lukyanova, a master's student at the Faculty of Physics and Technology of NSTU-NETI, there are many non-destructive testing methods that can be used to detect, for example, the presence of corrosion of dam elements or filtration zones in its body. The main method is a visual inspection, which allows you to see the consequences of possible defects that have already occurred. Each method has its own limitations related to the type of defects detected, and therefore none of them can be used as an independent method.
Therefore, it is important to develop a methodology that would allow an inspection for cracks, filtration and other defects in the body of the dam, without adversely affecting it and without stopping the operation of the hydroelectric power station. The study was conducted under the supervision of Konstantin Fedin, Associate Professor of the Department of Geophysical Systems at NSTU-NETI. In addition to Alina Lukyanova, Oleg Marilov, a graduate student at the University's Faculty of Physics and Technology, took part in it. The main task was to show that using non-destructive passive seismic methods, it is possible not only to diagnose the presence of defects in the dam body, but also to substantiate their appearance at a qualitative level. Work was carried out on the inspection of the hydroelectric dam located in the permafrost zone and the surrounding areas. The survey was conducted by two passive seismic methods: the standing wave method and the seismic emission tomography method.
One of the most interesting results obtained by combining the two methods is the localization of the filtration zone at a depth of 30 meters, which was revealed using the seismic emission tomography method, which had not previously been used in such studies. Filtration is the process of water passing through porous materials (in this case, through the body of a dam), and its timely detection is an extremely important task, since uncontrolled filtration is one of the most dangerous factors that can lead to an accident or destruction of a dam.
"Combining these methods allows us to obtain comprehensive information about the dynamic characteristics of the structure and increase the reliability of the results obtained. In addition, constant monitoring provides information about the object in dynamics, which allows not only to determine the state of the object at the moment, but also to predict its behavior in the future," said Alina Lukyanova.
During the inspection of the dam, more than 700 measuring points were performed, which made it possible to localize the identified defects with high accuracy. The results were processed using unique software developed by Andrey Skorobogatko, a master of the Department of Geophysical Systems at NSTU-NETI, and Anton Gritsenko, a graduate student at the Faculty of Geology and Geophysics at Novosibirsk State University.
The comprehensive methodology, developed with the support of INGG SB RAS, can be applied in other industries as well.: for mapping caves, detecting metal corrosion, flooding of buildings and structures, and surveying roadways and bridges. All this is important, first of all, to ensure the safe operation of facilities.
The reliability of the results obtained is confirmed by the analysis of long-term data on the water levels of the upper and lower reaches and the results of the subsequent complex of surveys by employees of the hydroelectric power plant. At the moment, a team of scientists is conducting a survey of buildings and engineering structures throughout Russia and abroad.
"In the future, we would like to introduce monitoring systems everywhere, equip hazardous production facilities with equipment that allows timely notification of changes in facilities, and expand the boundaries of the method's applicability," adds Alina Lukyanova.