Bearing capacity of circular footings resting on unsaturated desiccated soils

Abstract

When a clayey soil is exposed to desiccation, water evaporates from the surface. During dry periods, the soil may suffer from shrinking phenomena, the saturation degree decreases and formation of cracks begins. At the same time, an overconsolidated soil appears at the surface of the deposit. Some previous studies devoted to this problem have highlighted the impact of cracks on desiccated profiles. However, these analyses have been carried out without considering the suction effect. The present study examines the specific case of the cracked soils found in the area of Sabana de Bogotá in Colombia. In this research, some soil models are tested using the Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux's geotechnical centrifuge. In this paper, the experimental procedure is first described. Then, the experimental results for the bearing capacity are presented. Finally, an analysis of the bearing capacity is carried out by considering the matric suction effect. This analysis compares different theoretical methods used to calculate the bearing capacity of shallow foundations resting on unsaturated soils with the experimental results obtained using the centrifuge. The results of the analysis underline the necessity of considering suction for the computation of the bearing capacity of unsaturated soils.