Author(s): Vera Snezhko; Dmitry Kozlov; Olga Simonovich

Linked Author(s): Vera Snezhko

Keywords: Hydraulic structure; Groundwater dam; A model of reliability; Security

Abstract: There are more than 30 thousand hydraulic structures (HS) operating in the Russian Federation, of which 5% belong to energy and/or industry, and 95% objects are structures of the reclamation and water management complex. Dams made of ground materials of low hazard class on clay and sandy bases should have a height of up to 15 meters. When using retaining HS to create reservoirs for reclamation purposes, the volume of the reservoir should not exceed 50∙106 m3, and possible damage from an accident on a ground dam should not have economically significant consequences. The standard life is 50 years. Intensive construction of small HS began in the Soviet Union in 1966 after the adoption of the state program for the development of land reclamation. The economic crisis caused the bankruptcy of the owners of many small HS. They remained ownerless or became the property of organizations that do not have qualified hydraulic technicians or operational services in their staff. Most owners (farmers, agricultural cooperatives) are experiencing a shortage of funds not only for the repair of structures, but also for the diagnosis of their technical condition. Today, most of the HS have reached or exceeded the standard service life. The assessment of the reliability status of each of the structures is carried out by experts. A comprehensive qualitative indicator is determined – the level of safety of a hydraulic structure. The aim of the research was to forecast the safety level of ground dams commissioned during the Soviet period of intensive reclamation construction. The forecast interval included not only the standard service life (50 years old), but also went beyond it. The research material is data on the level of safety of soil homogeneous dams of low hazard class located on the territory of the Moscow region. The expert examination of the condition of ground dams was carried out in three stages: 1992-2013 for 1218 HS, 2016-2018 655 for HS, in 2020 - 247 HS. 70 HS were re-examined. Research methods are the system theory of reliability and the theory of random processes. The working conditions of the hydraulic structure were modeled by one of the standard methods of reliability analysis - the Markov chain. At the first two stages of the survey, a model was built to reduce the level of dam safety over time in the absence of repair and technical operation of the structure. The information obtained during the survey of structures at the third stage was used to verify the calculated dependencies obtained. The performed studies allow, based on the results of one expert examination of a soil dam, to make a forecast of a decrease in its safety level to the age of 55 years.

DOI: https://doi.org/10.3850/IAHR-39WC2521711920221707

Year: 2022