International Journal of Geosciences, 2017, 8, 1231-1250 http://www.scirp.org/journal/ijg ISSN Online: 2156-8367 ISSN Print: 2156-8359 DOI: 10.4236/ijg.2017.810071 Oct. 27, 2017 1231 International Journal of Geosciences Analysis of the Bearing Capacity of Shallow Foundation in Unsaturated Soil Using Monte Carlo Simulation Nadarajah Ravichandran, Vahidreza Mahmoudabadi, Shweta Shrestha Glenn Department of Civil Engineering, Clemson University, Clemson, SC, USA Abstract The ultimate bearing capacity of shallow foundation supported by unsatu- rated soil depends on the degree of saturation of the soil within the influence zone because the strength and deformation parameters of soil are affected by the degree of saturation. As the degree of saturation varies with rainfall, sur- face runoff, evapotranspiration and other climatic and geotechnical parame- ters, these parameters must be systematically incorporated for accurately computing the ultimate bearing capacity. In this study, a framework is pro- posed to compute the ultimate bearing capacity of a shallow footing in unsa- turated soil considering site specific rainfall and water table depth distribu- tions. The randomness in rainfall and water table depth is systematically con- sidered using Monte Carlo method. The infiltration of water through the un- saturated zone is modelled using Richards equation considering infiltration and water table location as the top and bottom boundary conditions, respec- tively. The results show that the bearing capacity calculated using the pro- posed method is approximately 2.7 times higher than that calculated using the deterministic approach with fully saturated soil parameters. Keywords Unsaturated Soil, Shallow Foundation, Rainfall Data, Geotechnical Design, Monte Carlo Simulation 1. Introduction Shallow foundations are typically considered as the simplest and most economi- cal foundation for supporting small to medium size structures. They transfer the structural loads to the near surface soil that is mostly unsaturated and fluctuates How to cite this paper: Ravichandran, N., Mahmoudabadi, V. and Shrestha, S. (2017) Analysis of the Bearing Capacity of Shallow Foundation in Unsaturated Soil Using Monte Carlo Simulation. International Journal of Geosciences, 8, 1231-1250. https://doi.org/10.4236/ijg.2017.810071 Received: January 18, 2017 Accepted: October 24, 2017 Published: October 27, 2017 Copyright © 2017 by authors and Scientific Research Publishing Inc. This work is licensed under the Creative Commons Attribution International License (CC BY 4.0). http://creativecommons.org/licenses/by/4.0/ Open Access