Three-dimensional analysis of a concrete-face rockfill dam

The behaviour of a proposed concrete-face rockfill dam and its face slab during first impounding are examined using three-dimensional finite-element modelling, verified by results of empirical relationships and observed behaviour of similar dams. The study is carried out on the Glevard dam, a 110 m high concrete-face rockfill dam with a crest length of 276 m. Two models are used for the face slab, one with vertical joints and one without. Friction contacts are used between the concrete face and the underlying rockfill, and between adjacent slab pieces, such that relative sliding at these contacts is allowed. Slab deformations and stresses, joint openings and axial forces obtained for the two models are compared. Results indicate that while neglecting face slab joints in the analysis may not significantly influence the calculated total deformations, it can result in substantial underestimation of in-plane horizontal deformations and axial forces, especially near the abutments. In-plane deformations influence the performance of water stops and leakage through slab joints, and axial forces influence slab design. Results also show that using relatively simple geometry and material modelling in a three-dimensional finite-element analysis can yield results in reasonably good agreement with the observed behaviour and the empirical relations obtained from similar dams.