Experimental and numerical analyses on working performance of a high arch dam with deep-seated joints: Yebatan arch dam, China

Abstract

High arch dams commonly face complicated geological conditions at the dam site, which is particularly prominent in numerous projects in the southwest mountainous area of China. The deep-seated joint is a special geological defect caused by unloading fracturing of the deep rock mass, which is unfavourable to the working performance of high arch dam projects. The Yebatan arch dam is a world-class high arch dam, situated in a deeply carved V-shaped gorge with deep-seated joint zones in both banks. In this paper, both geomechanical model test and numerical analysis are carried out to study the working performance of the Yebatan arch dam and abutment, which are affected by the deep-seated joint zones. The research results demonstrate that the deep-seated joint zones have a significant effect on the arch dam and abutment working performance. It is highly dependent on the location of the class IVS strong relaxed rock mass and the combination with faults. The class IVS strong relaxed rock mass in the left abutment has a great impact on the deformation of arch dam and abutment, and fault f29 (f74) plays a dominant role in controlling the anti-sliding stability of the right abutment. Subsequently, a kind of concrete replacement measure is proposed in order to treat these project weaknesses. The additional numerical analysis results indicate the deformation and stability performance of arch dam and abutment are greatly improved after reinforced. The reinforcement measure is effective for Yebatan project.