A Coupled Geotechnical-Hydrological Model for Computing Bearing Capacity and Settlement of Shallow Foundation

The loads from the civil engineering systems are ultimately transferred to the subsurface soil through various foundations and their load carrying capacity is greatly influenced by the degree of saturation (dos) of subsurface soil and matric suction within the influence zone. The dos of the subsurface soil and matric suction vary with climatic and hydrologic parameters such as rainfall, water table location, and temperature. In this study, a framework is proposed to evaluate the ultimate bearing capacity and elastic settlement of shallow foundation incorporating the site specific hydrological parameters such as historical rainfall and water table records. The results show that the ultimate bearing capacity obtained using the proposed coupled geotechnical-hydrological method is approximately 30% greater than that computed using the conventional method which assumes that the subsurface soil is fully saturated. Furthermore, the elastic settlement computed from the proposed method is approximately 60% smaller than that of conventional method. From this and the parametric studies, an increase in ultimate bearing capacity and a decrease in elastic settlement were observed for the site considered. It is also observed that the benefits are significant when the size of the footing increases.