Evaluation of the Bearing Capacity of Sandy Soils with Analytical and Numerical Methods

In the present study, the bearing capacities of coarse graded soils beneath the strip foundations were calculated by means of analytical and numerical methods. First all necessary geotechnical properties of the soil were achieved at seven different relative density values of the soil in terms of correlations between friction angle () and dry density (d). Second, 63 bearing capacity analyses of strip foundation systems were conducted by changing the soil parameters and the width of the foundations with analytical and finite element methods (FEM). The Mohr-Coulomb, elastic-plastic, model was chosen for this research. Although explicit analytic solutions were obtained without any difficulty, FEM provided only the load-deformation response at the base of the footing from the models. Because of that, some prediction methods were used to evaluate and find the bearing capacity of the soils beneath the foundation from the load-deformation responses. The results of analytic and numerical analyses of strip foundation laying on loose soil models gave very similar values. Although, very similar bearing capacity values of the foundations laying on dense soil models were calculated from the analytical methods, the results of numerical methods were very divergent and scattered at the same conditions. The reason for this is due to some limitations of the elastic-plastic model and prediction methods.

___

  • 1. Terzaghi, K. Theoretical Soil Mechanics; Harvard Univ. Press: John Wiley & Sons, America, 1943; pp 510.
  • 2. Meyerhof, G. 1943. The ultimate bearing capacity of foundations. Geotechnique; 2: 331-332.
  • 3. Vesic, A. 1973. Analysis of ultimate loads of shallow foundations Journal of the Soil Mechanics and Foundations Division; 99 (SM-1): 45-73. 4. Bond, A. and Harris, A. Decoding Eurocode; Press: Taylor & Francis, America, 2008; pp 616.
  • 5. Sieffert, J.G., Bay-Gress, C. 2000. Comparison of the European bearing capacity calculation methods for shallow foundations Geotechnical Engineering, Institution of Civil Engineers 143 65–74.
  • 6. Manoharan, N., and Dasgupta, S.P. 1995. Bearing Capacity of Surface Footings by Finite Elements. Computers and Structures; 54 (4): 563-586.
  • 7. Elhakim, A. Evaluation of Shallow Foundation Displacements Using Soil Small-Strain Stiffness; Georgia Institute of Technology, Civil and Environmental Engineering, Doctor of Philosophy, America, 2005; pp 396.
  • 8. Loukidis, D., Chakraborty, R., and Salgado, R. 2008. Bearing capacity of strip footings on purely fractional soil under eccentric and inclined loads. Canadian Geotechnical Journal; 45 (6): 768-787.
  • 9. Loukidis, D., and Salgado, R. 2009. Bearing capacity of strip and circular footings in sand using finite elements. Computers and Geotechnics; 36: 871-879. 10. Dağlı, E. Calculation of Bearing Capacity of Cohesionless Soils By Numerical and Analytical Methods; Zonguldak Bulent Ecevit Univ. Institute of Science, Master’s Thesis in Turkish, Turkey, 2013; pp 130.
  • 11. Ghazavai, M., and Eghbali, A.H. 2013. New geometric average method for calculation of ultimate bearing capacity of shallow foundations on stratified sands. ASCE International Journal of Geomechanics; 13 (2): 101-108.
  • 12. Nguyen, D.L., Ohtsuka S., and Kaneka, K. 2016.. Ultimate Bearing Capacity of Footing on Sandy Soil Against Combined Load of Vertical, Horizontal and Moment Loads. Int. J of Geomate; 10 (1): 1649-1655.
  • 13. Yahia-Cherif, H., Mabrouki A., Benmeddour D., and Mellas, M. 2017. Bearing Capacity of Embedded Strip Footings on Cohesionless Soil Under Vertical and Horizontal Loads. Geotech Geol Eng; 35: 547-558.
  • 14. Sakleshpur, V.A., and Reddy, C.N.V.S. 2017. A Comparative Study on Bearing Capacity of Shallow Foundations in Sand from N and ϕ. J. Inst. Eng. India Ser. A; 98 (4): 355-365.
  • 15. Bowles, J. Foundation Analysis and Design; Harvard Univ. Press: McGraw-Hill, America, 1995; pp 1230.
  • 16. Geostudio, Stress-Deformation Modelling with Sigma/W 2012 Geo-Slope International Ltd; Canada, 2012; pp 221.
  • 17. Potts, D.M. and Zdravkovic, L. Finite Element Analysis in Geotechnical Engineering Volume 2: Application; Press: Thomas Thelford Publishing, England, 2001; pp 427.
  • 18. Hansen, B. 1963. A general formula for bearing capacity. Danish, Geotechnical Institute, Bulletin; 11: 38-46.
  • 19. De Beer, E. 1970. Experimental determination on the shape factors and the bearing capacity factors of sand. Geotechnique; 20 (4): 387-411.
  • 20. Chin, F. 1971. Discussion to pile tests: Arkansas river project. ASCE Journal of Soil Mechanics and Foundation; 97 (6): 930-932.
  • 21. Amar, S., Baguelin, F., Canepa, Y., and Frank, R. 1994. Experimental study of the settlement of shallow foundations. Vertical and Horizontal Deformation of Foundations and Embankments; 2 (40): 1602-1610.
  • 22. Decourt L 1999. Behaviour of Foundations under Working Load Conditions, Proceedings of The XI Panamerican Conference On Soil Mechanics And Geotechnical Engineering; Foz Du Iguassu, Brazil, 4: 453-487.
  • 23. Navfac DM-7.02. Foundations & Earth Structures Design Manual 7.02, Washington, 1986; pp 279.
  • 24. Bolton, M. D. 1986. The strength and dilatancy of sands, Geotechnique; 36 (1): 65-78.
  • 25. Budhu, M. Foundations and earth retaining structures, John Wiley & Sons, Arizona, 2007; pp 483.