A Review on Thermo-mechanical Modelling of Arch Dams During Construction and Operation: Effect of the Reference Temperature on the Stress Field

Abstract

Double-curvature dams are unique structures for several reasons. Their behaviour changes significantly after joint grouting, when they turn from a set of independent cantilevers into a monolithic structure with arch effect. The construction process has a relevant influence on the stress state, due to the way in which self-weight loads are transmitted, and to the effect on the dissipation of the hydration heat. Temperature variations in the dam body with respect to those existing at joint grouting generate thermal stresses that may be important in the stress state of the structure. It is thus essential to have a realistic estimate of this thermal field, also called reference or closing temperature. In this work, the factors involved in the calculation of the reference temperature of double-curvature arch dams are analysed: material properties, boundary conditions and numerical aspects. First, a critical review of the state of the art is made with respect to the criteria used by various authors for decision-making in the construction of the model. Next, specific analyses are made on the effect of some important elements: the time step, the size of the domain of analysis and the methodology used for the calculation of the reference temperature. The results show the relevance of a correct calculation of the closing temperature to adequately determine the stress state of the structure.