Comprehensive Characterization of Soils with Analytical and Numerical Simulation for Bearing Capacity and Settlement Requirements of the Footing

Abstract

Characterization and analysis of foundation material are basic concerns of geotechnical activities to have safety for the structure and users as well. Particularly, it is quite important for the areas of lagging experiences with a lack of equipment and accessibility to investigate the subsurface conditions sufficiently. This study was designed for comprehensive soil investigations through analytical and Plaxis 2D simulation by considering square footing in Bule Hora town, Southern Ethiopia. Considering the investigation depth up to 5.0 m, fourteen soil samples at 1.5 m and 3.0 m depths (two samples from seven pits) were collected, and physical and engineering properties were investigated. Grain and consistency results indicated that soils lying between low to high plastic silt regions. Undrained shear strength (Cu) ranges from 49.5-–64.30 and 52.40–103.10 kN/m2 at 1.5 m and 3.0 m depth, respectively. An average allowable bearing capacity of 145.35 kN/m2 with a settlement of 40.77 mm at 1.5 m depth and 191.41 kN/m2 with a settlement of 47.84 mm at a depth of 3.0 m using the analytical method whereas 122.72 kN/m2 was obtained with the settlement of 30.57 mm at a depth of 1.5 m and 155.11 kN/m2 with 29.08 mm at depth of 3.0 m using Plaxis 2D analysis. The results of bearing capacity and settlement analyzed by the numerical method are lower than the analytical method, which confirms that comparatively, Plaxis 2D analysis gives a better output in selected square footing of shallow foundations. In conclusion, Plaxis was a preferable analysis tool for a shallow foundation, square footing, using inputs of the exhaustively investigated actual condition of soils specifically in Bule Hora town.