Influence of water pressure on crack propagation in concrete dams

Aim of the paper is to study crack propagation in concrete dams taking into account the water pressure effects. With this aim, an interface model, based on the cohesive fracture, is developed in order to simulate the presence of the process zone at the crack tip, which significantly influences the crack growth in cementitious materials. In particular, a damage-plastic model is proposed for the interface, which is able to simulate crack propagation in mode I, mode II, and mixed mode. The criteria for crack initiation and propagation and the closure and reopening of the crack are considered for the interface. The water pressure effects are taken into account by considering the water pressure as a further static pressure acting on the real crack and in the process zone. The value of this pressure is set as an exponential function of the crack opening displacement and it varies from zero to the external water pressure. A numerical procedure is developed in order to integrate the evolutive laws governing the interface model. The interface model is implemented in a finite element code; some numerical simulations for the analysis of a dam are presented in order to validate the proposed model and to investigate the influence of the water pressure effects on the crack propagation.