Grouting of cracks in concrete dams: numerical modelling and structural behaviour

Abstract

Abstract Grouting is often considered to reinstate water tightness and displacement continuity in cracked concrete dams. Grouting alters the state of stress, deformation, and the strength of a dam in many ways. The state of stress prior to grouting is altered by the injection pressure that often increases the crack opening. This new state of stress will be ‘locked‐in’ as the grout sets. Excessive injection pressure may also induce hydro‐fracturing. Obviously, composite action of structurally repaired cracks will be fully effective only for incremental load applications occurring after the completion of the grouting programme. The state‐of‐practice concerning structural response of cracked dams during and after grout injection is reviewed in this paper. The existing methods for structural analysis of dam rehabilitation by crack grouting, and the required modifications for modelling the hardened grout in the repaired dam are discussed. State‐of‐the‐art techniques using contact elements are defined (i) to model the hardened grout in cracks of repaired dam; and (ii) to investigate the structural response of the rehabilitated dam to subsequent loading conditions. A 90 m high‐gravity dam is considered in comparative analyses for numerical simulations of the incidence of grouting on the structural responses of cracked dams.