Verificação da estabilidade do talude de montante em barragem de terra submetida a rebaixamento rápido realizada com ensaios em solos não saturados e modelagem numérica

Abstract

With the passage of time, the population has depended on works for the storage of water for the periods of scarcity, the same need that led to the construction of dams that have played a very important role in human development. Not yet development of an earth dam project, the slopes are pre-dimensioned with based solely on the classification of the soil to be used in the massif, and stability analyzes of Slopes are made in different situations, such as the situation of rapid lowering, in which the water rapidly lowers so that it does not allow complete dissipation of the pressures interstitial within the dam massif at the same time as Water. However, depending on the type of material, the soil in the unsaturated state may have a resistance during rapid emptying, as the poropression is dissipated and the increase of suction occurs in the upstream slope. Another important factor to highlight is the definition of slope inclination, since the height of the work is not taken into account and consequently the level of existing tensions, thus, the use of this methodology can lead to oversized projects for small dams and undersized projects for large dams. In view of this, the present work has objective of assessing the stability of the slope of the amount of land dams submitted to for different geometric variations and in the context of unsaturated soils. The study involved the use of dam data from the Experimental municipality of Quixadá, for a more realistic analysis of the behavior of the work. The parameters geotechnical aspects of the material used were obtained from results of characterization tests, compression, triaxial compression (saturated and unsaturated), for the determination of the soil retention curve (filter paper method) presented by Leme (2015). For other types of soil commonly used in dam works, to the use of bibliographic references to estimate the parameters required for the analyzes. Taking the clear perspective, the study verified the behavior in the rapid demotion, using the GeoStudio 2007 Finite Element software for flow modeling and stability analysis of a hypothetical mass. As results obtained, it was verified that the stability values ​​for the upstream slope were identified slope that is usually applied in practice, due to the increase in soil resistance by the influence of the soil in the unsaturated state. It was also possible to define for each type of critical slope of the slope of the amount according to the height of the work, verifying a great conservatism in current dam pre-sizing methodologies.