Stability analyses of dam abutments by 3D elasto-plastic finite-element method: a case study of Houhe gravity-arch dam in China

This paper studies the stabilities of the abutments of Houhe gravity-arch dam using elasto-plastic finite element analyses and block theory. The gravity-arch dam is constructed by expanding the existing gravity dam. Due to the complex geologic conditions, the natural abutments do not meet the stability requirements. Engineering measures including concrete plugs and concrete backfills are thus designed to increase the safety of both abutments. The effectiveness of these measures is evaluated in this study. The paper performs three-dimensional elasto-plastic finite element analyses to obtain the stress and deformation characteristics of the abutments and the dam. The stabilities of sliding blocks on the abutments are then evaluated by incorporating the results of finite-element method analyses. It is found that the use of concrete plugs significantly increases the factors of safety against sliding for both abutments. Concrete backfills not only provide the sliding resistance, but also are effective in reducing the deformation of the abutments and improve the stress conditions along the base of the dam. The dam works under satisfactory conditions as the results of applying these engineering measures.