Otimização de barragens de terra e de concreto construídas sobre solos argilosos.

Abstract

It is known that civil engineering projects entail significant costs and often suffer from inadequate design, resulting in inefficiencies such as cracks and, in extreme cases, structural failure, posing risks to both the population and the local environment. Optimization techniques, aided by mathematical methods and software tools, are employed to address these issues by calculating various possibilities within the scope of the studied problem. Therefore, for costly structures like dams, which play vital roles in society regarding water storage and electricity generation, the construction's operating costs and structural efficiency concerning different materials in their composition are estimated. This work's implementation will provide a better understanding of which material is more suitable for building the dam, concrete or earth, from both an economic and technical-quality perspective. It will also determine the most suitable type of foundation soil, whether soft clayey soil or hard soil, aiming for improved system efficiency as a whole. All of this is made possible through the Solver module of Microsoft Excel, which optimizes the length of the hypothetical dam's cross-sectional base. At the end of the optimization process, satisfactory results regarding the length of the dam's base were obtained, compared to findings in Massad (2010), and the values of safety coefficients for sliding and overturning remained within the limits allowed by Eletrobrás (2003). It was also possible to analyze that the volume of material required for constructing the concrete dam is approximately five times smaller compared to the earth dam. However, due to the relatively high cost per cubic meter of concrete, situations involving the concrete dam showed nearly ten times higher cost values per linear meter compared to the earth dam. Therefore, the earth dam proved to be the more cost-effective material for the project. However, for enhanced safety combined with reduced material usage and consequently a smaller footprint, concrete became the more recommended choice. Finally, it is observed that for less resistant clayey soil (soft clay), the safety factor concerning sliding significantly decreases, making the situation more vulnerable and potentially requiring a greater volume of material and higher implementation costs.