Avaliação do desempenho de diferentes métodos de análise de estabilidade de taludes em barragens de terra

Abstract

The diversity of sizes and uses of dams and embankments, in Brazil, is reflected, in terms of these structures, too. Some are impeccably designed, meeting safety standards consistent with national and international standards more stringent, while others have serious risks that safety limits are exceeded, and may even result in the disruption of the structure, given the complexity and excessive hand-labor calculations of slope stability. The aim of this study was to evaluate the performance of the methods of slope stability analysis less accurate, to reduce the number of operations which make use the most accurate methods available in the literature. The development work was given from the performance index of 4 methods of calculating slope stability, being Fellenius (1936), Bishop (1955), Simplified Bishop (1995) and Janbu Simplified (1973) compared with the method of Spencer (1967) considered an exact method for calculating the safety factor, however, which requires more computational time to obtain the results. The procedure was performed in scenarios with different soil types, heights and inclinations of slopes, and for conditions subject to reservoir emptying fast and slow. Based on the calculated FS values were adjusted linear regression equations, where the dependent variable was obtained by the FS equation Spencer, and independent variable FS values estimated by other methods. Thus, comparative analyzes were performed using the correlation index "r" accuracy "d" (WILLMOTT et al., 1985) and performance "c" suggested by Camargo & Sentelhas (1997). The methods we have obtained optimum performance for all conditions with the highest levels of trust were Simplified Bishop and Janbu Simplified, and the values obtained by these FS calculated determination coefficients of 99% and 96.59%, respectively, and can be used alternatively, replacing the Spencer s method, in the analysis of slope stability in earth dams.