Geological-Geotechnical Characterization of Slopes Belonging to the Serra do Mar Paranaense, Brazil

Abstract

An extensive campaign of field and laboratory tests were performed on samples of residual soils and colluviums present in the morphoscultural sub-unit comprising Serra do Mar Paranaense located in Southern Brazil. The geotechnical investigations included the physical characterization, in situ hydraulic conductivity and the mechanical behavior of the soils, by means of conventional direct shear tests, smooth interface direct shear tests, and CIU triaxial tests. The results showed that both the superficial colluvium and residual soils found along this stretch have similar granulometry, generally classified as silty sand soils, with in situ hydraulic conductivity of around 10-4 cm/s. Grain size curves show less dispersion in the case of residual soils compared with colluvial soils. The residual and colluvial soils had average peak and residual friction angles of 32° and 26°, respectively, with variations and differences attributed to the complex variety of the lithotype present in the region. Regarding cohesive intercept, a greater disparity was found in the results; however, these results corresponded to the literature. These results are relevant because they provide a framework to evaluate the stability of road slopes, together with other pertinent information, such as slope declivities and layers, water table, suction parameters and rain scenarios, both in specific cases within or close to the region, and in areas of similar geological material.