1 MONITORING AND DEFORMATION ASPECTS OF LARGE CONCRETE FACE ROCKFILL DAMS

Abstract: Concrete face rockfill dams (CFRDs) are gaining a worldwide recognition as the most economical type of dams to be constructed in extreme northern and sub-Antarctic regions. Height of CFRDs may exceed 200 m. Safety of CFRDs depends on the proper design, construction, and monitoring of actual behaviour during the construction and during the operation of the structure. The main concern for the safety of CFRDs is the deformation of the concrete face. During the reservoir filling, the load of the water and deformations of the dam rockfill, force upstream concrete slab to deform. The displacements of the concrete face during the reservoir filling should not exceed the maximum allowed values in order to maintain the structural integrity of the concrete face. In a classic CFRD where the concrete face is constructed after the end of construction of the rockfill embankment, it is very important to estimate the displacements of the concrete face during the filling of the reservoir and to verify if these displacements are lower than displacements compatible with the structural integrity of the concrete face. Due to the uncertainty of the model parameters, careful monitoring of the dam and its surroundings are required in order to verify and enhance the model. The paper presents a study of behaviour of the Shibuya Dam in P. R. China, the tallest (233 m) concrete face rockfill dam in the world using results of monitoring and FEM analysis. The study shows that the in real time fusion of the monitoring results and FEM analysis would give indication that the deformations of the concrete face reached critical values before the reservoir level reached the maximum level. This information could trigger the proper action from engineering team and lead to prevention of the cracking of the concrete face