Influência da sucção na estabilidade de um aterro no campus Glória da UFU

Abstract

The use of unsaturated soils theory in civil engineering designs is not usual in practice, which is in part due to the complexity of such theories. One of the main characteristics of the unsaturated soils is the occurrence of suction, which happens when the water partially fills the voids of the soil, resulting in negative pressures. The negative pore water pressure in the soil affects its mechanical behavior, increasing the resistance significantly, in a way that it becomes sufficient to maintain slope stability. In this context, the objective of this work is to analyze the influence of suction on the stability of unsaturated slopes, through laboratory tests and software Slide 2018, in order to better understand how the unsaturated condition can be considered in geotechnical works. The contribution of suction in the shear strength of the soil was considered by increasing the apparent cohesion based on the model of Vilar (2007). The model was calibrated using experimental results of direct shear tests in saturated soil and unconfined compression in air-dried soil. The stability analyzes were performed for three scenarios: 1 - landfill with saturated parameters, 2 - landfill with uniform suction resulting from compaction (unsaturated parameters), and 3 - landfill with linearly increasing suction from the water table up (unsaturated parameters). The safety factors were 1.05, 4.56 and 2.58, respectively. Thus, based on scenario 1, the safety factor was 335% greater in the post-compaction condition, and 155% greater in the hydrostatic equilibrium from scenario 2.