Parametric Study of Concrete Dam Stability in the Case of Gallery and Tailwater Existence

Abstract

A concrete gravity dam can simply be defined as a large structure constructed of concrete that can hold back and also store a large amount of water. Since it is held by gravity to the ground, the stability of the massive concrete dam depends on its weight. Concrete dam is subjected to many kinds of static and hydrodynamic forces which need considering design under different circumstances to satisfy the safety requirements. The shape of the dam is essential to settle the stability of the dam regarding the major forces and stresses. As the stability of the concrete dam depends on its weight, which in turn depends on the shape of the dam as concrete density is constant, the initial design using the preliminary section of the dam does not certainly lead to obtaining safety factors for the different failure modes. Therefore, this requires an increase in the dam base which consequently increases the dam weight and provides safety requirements. In this paper, the concrete dam was designed for different values of the storage water level, tailwater depths, in addition to the presence of the gallery in the dam. The stability analysis for the most common modes of failure is carried out by the Microsoft Excel program, and all the relevant safety factors have been satisfied for the cases gallery existence and different tailwater depths. The results show that tailwater has a significant effect on additional base part values required for safety in addition, this effect is extended obviously on the upstream values of shear and principal stresses. Many regression equations have been obtained from results analysis to facilitate the estimation of additional parts and the main stresses.

Keywords

• concrete dam
• dam stability
• dam stresses