Static and Dynamic Analysis of Stress and Deformations of Răstoliţa Dam

Abstract

Large Dams are a particularly important case of seismic risk assessment. On the one hand, the dams themselves have a high value, having implications for the whole economy, through the production of electricity, water supply systems for irrigation and flood prevention etc. On the other hand, structural damage of a dam can lead to major disasters, the population exposure to effects caused by sudden floods. The situation in Romania is such that attention should be paid to the future safety of existing dams. The first reason is that these dams were designed and constructed on the basis of technical rules, which the majority are no longer in force; a second reason is the major climate changes in the last period, which have led to the accumulation of a large volume of water in increasingly large lakes. A third reason is, logically, the length of existing dams. In this paper is analysed the stress - deformation state that occurs in Răstoliţa dam body according to the type of rockfill; calculations were done for two cases, namely the completion of construction and, respectively, at the first filling of dam with water. The results show that after completion of construction, the maximum settlement is recorded in the central area of the dam, below the middle third; horizontal displacements of downstream prism are significantly higher compared to deformations of the upstream prism, in the area where the used material has a higher compressibility. Maximum principal normal stress registers some local distortions within acceptable limits; minimum principal normal stress presents important gradients in the contact zone downstream dam slope in the Ist stage with tuff-pyroclastic embankment layer and also in the first three layers of intercalated filling disposed near the slope. Stress increases due of hydrostatic pressure after the first filling does not lead to occurrence of stress concentrations in other zones than those reported at the completion of construction.