Avaliação da alteração de resistência ao cisalhamento com a inundação em um solo potencialmente colapsível

Abstract

Collapsible soils are unsaturated soils that undergo a saturation process and present a sudden reduction in volume. In the northern region of the state of Rio Grande do Sul, more precisely in the city of Cruz Alta/RS, there are unsaturated lateritic soils with medium to clayey texture. A series of cracks and fissures in buildings were found in this city after soil flooding events, typical pathologies of the occurrence of the phenomenon of soil collapse. Predicting the behavior of this soil is a challenge for Civil Engineering. The soil used in this study comes from the Experimental Field of Geotechnical Engineering established at the Universidade de Cruz Alta (UNICRUZ). This soil presents an acceptable stress-strain behavior for civil works when dry, however when flooded the land may be subject to differential settlements that generate unplanned efforts in the foundation design. In view of these facts, the objective of this work is to evaluate an accessible way that does not generate high costs to the final budget of the work, in order to mitigate the deleterious effects of this type of soil on the executed structures. The method chosen to avoid this problem in this study is the soil compaction method, which presents good results and has relatively low costs. This method is widely known and available in the geotechnical studies literature. The soil was compacted at optimum moisture with the intention of achieving the highest degree of compaction possible. Soil strength can be calculated basically by the resistance that the soil has exposed to shear forces, called soil shear strength. The test used in this study to determine soil strength parameters was the Direct Shear Test. From this perspective, with the interpretation of the results obtained in the work, it is legitimate to consider that the soil compaction method can be used to mitigate the problems generated by the phenomenon of soil collapse found in the city of Cruz Alta.