PROBABILISTIC RELIABILITY ASSESSMENT OF GATEWAY HEADS BY THE CRITERIA OF STABILITY AGAINST DISPLACEMENT ON THE EXAMPLE OF HYDRO SCHEMES OF THE DNIEPER CASCADE

Abstract

When calculating and designing modern hydraulic structures, it becomes necessary to assess their reliability and safety based on probabilistic methods. This work further develops the method for assessing reliability of gateway heads by the criteria of stability loss against displacement and overturning.The work considers the random nature of the external loads and impacts, which the gateway heads bear during operation, as well as correlations between them. It also considers the random nature of mechanical properties of the foundation soils and correlations between them. The suggested method allows assessing reliability by the criterion of stability loss against displacement of the gateway heads located both on rock and non-rock foundations. For solving this problem, the method of statistical tests (Monte Carlo method) was applied, which is widely used for assessing probabilistic reliability of complex technical systems.A numerical probabilistic assessment of the risk when the gateway heads on rock and non-rock foundations at hydro schemes of the Dnieper Cascade reach the boundary conditions has been performed. Confidence limits of the probability of losing stability of the gateway heads against displacement are determined; a number of statistical tests required to achieve confident accuracy is determined.Correctness of the obtained results is confirmed by their correspondence with the reliability assessment of the gateway heads of the Dnieper cascade by deterministic analyses using the method of boundary conditions.In the future, the proposed method could be used in probabilistic reliability analyses of hydraulic structures and cascades of hydro schemes, taking into account the correlations between natural factors: hydrological characteristics, wind, and ice, as well as temperature loads and impacts.