Retroanálise da estabilidade de um talude rodoviário da região de Curitiba

Abstract

This paper presents a back analysis of a slip on a road slope in the Curitiba - Ponta Grossa roadway (BR 376), km 4040, located in Curitiba, Paraná. This roadway is one of the main transport corridors of agricultural and industrial products of the state, mitigate the risks is very important. The soil is in Guabirotuba forming region and is classified as sandy-silt, according standard D-2487 (ASTM, 2011). Through direct shear test it was obtained an intercept of 13,45 kPa cohesion and angle of internal friction of 25,85º for this soil. The slope have a rotation failure type, so it is determined the most likely cause of the slip, making assumptions cases about why this may have occurred. A model of the initial slope geometry was inserted into the computational tool SLOPE/W (GeoStudio, 2007), and with parameters of the soil, it was determined the safety factor, by Spencer method, resulting in a factor equals 2,18 to the slope in dry state and 1,42 for the slope in partially saturated state. Through analysis, it is concluded that the slope is stable at the point of rupture. For the slope in partially saturated state, it indicates the application of deep drains with 2,5 meters, in order to obtain the safety factor above 1,5, recommended by NBR 11682 (ABNT, 2002). The first hypothesis is due a infiltration located on the landing above, causing a flow of water, lowering cohesion to 8.62 kPa, reaching the unit safety factor. Another hypothesis is a layer with another soil in place of the rupture, with unequal parameters to those obtained in the laboratory. Finally, the last hypothesis is a repression in the disruption of the slope region, resulting in a soil dry period after cracking, resulting in the existing failure