Development of a methodology for detecting the thawing permafrost soils at the base of bridge supports based on the oscillation frequencies diagnostics

Currently, the issue of the development of the northern regions of Russia due to the expansion of the network of railways and highways is acute. However, the regulatory framework for the design, construction and operation of bridges does not fully take into account the impact of natural and climatic changes, as well as the degradation of frozen soils on artificial structures throughout their life cycle. In order to improve building codes, it is necessary to conduct research about the problems arising in the process of operation in the conditions of the Far North. The creation of methods to solve these problems will improve the operational reliability of existing bridges. Therefore, it is necessary to develop a system for monitoring and maintaining artificial structures, including improving methods for monitoring the technical condition of bridges. Within the framework of this study, such methods as vibration diagnostics, electrotomography, electro profiling and georadar sounding were used to examine bridges built in the cryolithozone. The research was carried out at a landfill of 21 road bridges located on the Surgut – Salekhard and Labytnangi – Harp highways. The comparison of the considered methods testifies to the prospects of the method of vibration diagnostics. The natural oscillation frequency of the structure is taken as the main controlled parameter. A change in the frequency of vibration of the supports will indicate a change in the stiffness of the base of the bridge supports and the thawing of frozen soils. To better substantiate the results of the study, it is planned to organize monitoring of soil temperature, as well as perform geological surveys with the specification of the characteristics of the foundation soils.

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