A three-dimensional procedure for evaluating the stability of gravity dams against deep slide in the foundation

In the design of a gravity dam, any dam monolith must be checked to determine if the stability against sliding along a potential failure surface in the foundation meets the requirement specified by the design code. Till date, such verification is usually carried out based on two-dimensional limit equilibrium methods. Two-dimensional analyses are sometimes too conservative to meet the requirements. For this purpose, in the context of the limit equilibrium methods, a rigorous three-dimensional procedure is developed, which can accommodate failure surfaces of any shape and satisfy all equilibrium conditions. Meanwhile, the procedure considers the reinforcement of concrete plugs that are laid between the sliding body and the rock foundation. On the base of distribution of factors of safety of all dam monoliths, an idea called “the design of equal safety” is suggested, which says that all monoliths should have nearly equal factors of safety as far as possible.