Análise tensão deformação de uma barragem de concreto em solo residual preponderantemente anisotrópico.

Abstract

The design of engineering structures such as concrete-gravity and earth dams should account for all forces acting on the foundation to predict stresses and strains throughout the construction and post-constructive periods. For good quality rocks, the most common choice generally favors the use of concrete dams. However, for soil foundations, the most accepted solutions rely on earth dams. In both cases, classical limiting equilibrium stability analyses and isotropic numerical stress-strain analyses are commonly used in design. Under more adverse foundation conditions, the behavior of rocks and soils with marked anisotropy and inherited relict structures, anisotropic constitutive models provide predictions that are more realistic and contribute to a better understanding of these structural features. This dissertation aimed to demonstrate the use of an anisotropic constitutive model in the stability analysis of the foundation of the San Juan Dam, in the Dominican Republic, which was conceived as a concrete gravity-type structure supported by highly anisotropic young residual soils. Despite the small height of this dam, the intense presence of discontinuities has resulted in more detailed stress-strain analyses of the foundation, taking into account a detailed survey of the discontinuities in the soil mass and the results of direct shear tests parallel and normal to the most dominant discontinuities. To estimate settlements, the Author developed statistic correlations to estimate the Young's modulus (Es) based on many correlations of the shear wave velocity vs versus the SPT blow count based on many publications available in the literature. The Author carried out the analyses by the finite element program Plaxis 2D, using the constitutive model The Jointed Rock Model , which is particularly recommended for stability and stress-strain analyses of anisotropic materials. The numerical results were compared to limit equilibrium analyses carried out for the design of the San Juan Dam using he rigorous method of Morgenstern and Price, which proved to be conservative. The numerical analyses clearly showed the versatility of the numerical model to improve the overall stability of the dam by means of a cut off trench through the anisotropic soil foundation.