Abstract: Cracks are very likely to occur due to complex loads endured by concrete spiral case during the operation of hydropower station. Seepage control design is hence a big problem needs focus. Owing to insufficient research of seepage control at present and more applications of concrete spiral case in low and middle and even high head power stations in the future, some seepage control measures for concrete spiral case were analyzed by nonlinear finite element method with a hydropower station in river channel as the research background. The research results indicate that high strength concrete, steel fiber-reinforced concrete and epoxy mortar materials could solve the cracking problem for the concrete spiral case structure, but they have some limitations in practice. Steel liner coating on the inner wall of concrete spiral case and pre-stressed reinforcement have good effect in dealing with seepage problem and they are recommended to be preferentially used in practical projects.

Key words: concrete spiral case, nonlinear finite element method, cracking restriction, seepage control measures, concrete damage