Slope stability analysis of a dam. Case study: Hălceni Reservoir, Iasi county, Romania

Considering the overall behavior monitoring of an earth dam, the infiltration regime and the stability of slopes are the most important aspects to be considered, in order to permanently assess the technical status of the dam and its risk of collapse or breach. This paper presents the stability analysis for the upstream slope of Halceni Dam, performed by the finite element stability method, using SLOPE-GeoStudio program, under the condition of the drawdown water level. Firstly, the infiltration curve in the dam was drawn with SEEP/W-GeoStudio program, according to the maximum level measured during the flood in June 2019. The effects of slow drawdown and rapid drawdown from the maximum water level in the reservoir were analyzed. Built-in finite element algorithms used in the SEEP/W and SLOPE/W solved the analysis and the results were obtained as a range of Factor of Safety (FS) values, that were later compared to the admissible Factor of Safety established in the legislation and the technical regulations in force in Romania. Both the measured parameters and the visual observations showed that the dam performed exceptionally well, in accordance with design specifications and predicted behavior for the evolution of the response parameters to external stresses.