Engineering and Technology Journal

3D Numerical modeling of Soft soil Improved by Rigid Inclusions Supported an Embankment

Document Type : Research Paper

Authors

1 LGCE, Université Mohammed Seddik Benyahia BP 98 Ouled aissa

2 LGCE, Université Mohammed Seddik Benyahia BP 98 Ouled aissa

Abstract

Abstract
A three-dimensional finite element model suggested to determine the settlements and stresses of an embankment placed on soft soil reinforced by rigid inclusions. To make it simple the layers of soil and the embankment are supposed to be horizontal in a semi-infinite medium and the base of the soft soil is supposed to be rigid (bedrock). The interacting elements of the model are supposed to be elastic. The determination of the behavior of the soil-inclusions-embankment system was realized according to the construction phases of the embankment layers. The settlements and stresses were calculated according to construction phases of the embankment layers. At the end of each calculation phase, the stress field and the displacement field are extracted. The values are then introduced into the model the beginning of the next phase. The obtained results are presented in terms of the (settlement) vertical displacements and vertical stresses for the elementary cell and the global model respectively. This study allows the observation of three-dimensional interactions; the mechanisms of load transfer and the interaction between the different zones of the embankment. The numerical calculations are much lower than those measured in situ. A verification calculation on the stresses transmitted by the rigid inclusion shows that only 90% of the total load is applied with the numerical calculation.

Graphical Abstract

Highlights

  • Numerical modeling of soft soil reinforced by rigid inclusions.
  • Calculation of settlements and stresses under the placement of embankment layers
  • The settlement at the embankment soil interface has been reduced by 90% compared to a soil without reinforcement.
  • Despite the problems encountered with elastoplastic calculations, a good distribution of the stresses in the inclusions is obtained. The charge transfer mechanism is well done for the elementary cell.

Keywords

Main Subjects

References
[1] L. Briançon, R. Kastner, B. Simon, D. Dias,  Etat des connaissances - Amélioration des sols par inclusions rigides. Symp. Int. sur l'Amélioration des Sols en Place. ASEP-GI, 9-10 septembre 2004, Paris, Presses de l'Ecole Nationale des Ponts et Chaussées, (2004) 15-44.
[2] Jenck O., Dias D., Kastner R. (2005) Two Dimensional Physical and Numerical Modelling of a Pile-Supported Earth Platform over Soft Soil. Journal of geotechnical and geoenvironmental engineering. ASCE / March 2007.
[3] Simon B., Schlosser F. (2006). State of the Art, So il reinforcement by vertical stiff inclusions in France, in: SYMPOSIUM Rigid Inclusions in Difficult Subsoil Conditions. Mexico City.
[4] Fitz Patrick, B., R. Gernant, and J. Micelli. 2009. Design and construction of intermediate foundation solutions for wind turbines. In Contemporary topics in deep foundations, Geotechnical Special Publication 185, edited by M. Iskander, D. F. Laefer, and M. H. Hussein,  (2009) 504-511. Reston, VA: ASCE .
[5] Chen, R. P., Y. M. Chen, J. Han, and Z. Z. Xu. A theoretical solution for pile-supported embankments on soft soils under one-dimensional compression. Can. Geotech. J. 45 (2008), 611-623. https://doi.org/10 .1139/T08-003.
[6] Deb, K. 2010. A mathematical model to study the soil arching effect in stone column-supported embankment resting on soft foundation soil. Appl. Math. M.
[7] Zhang, L., M. Zhao, Y. Hu, H. Zhao, and B. Chen. Semi-analytical solutions for geosynthetic-reinforced and pile-supported embankment." Comput. Geotech. 44 (2012) 167-175. https://doi.org/10.1016 /j.compgeo.2012.04.001.
[8] Deb, K., and S. R. Mohapatra. Analysis of stone column-supported geosynthetic-reinforced embankments. Appl. Math. Modell. 37 (2013) 2943-2960. https://doi.org/10.1016/j.apm.2012.07.002.
[9] Mestat, P., Bourgeois, E., and Riou, Y. Numerical modelling of embankments and underground works. Computer and Geotechnics, 31 (2004) 227-236. doi:10.1016/j.compgeo.2004.01.003.
[10] Mattson, N., Menoret, A., Simon, C., and Ray, M. 2013. Case study of a full-scale load test of a piled raft with an interposed layer for a nuclear storage facility. Géotechnique, 63: 965-976. doi:10.1680/geot.12.P.166.
[11] Han, J., and Gabr, M. Numerical Analysis of Geosynthetic-Reinforced and Pile-Supported Earth Platforms over Soft Soil. Journal of Geotechnical and Geoenvironmental Engineering, 128 (2002) 44- 53, doi: 10.1061/(ASCE)1090-0241(2002)128:1(44).
[12] Jenck, O., Dias, D., and Kastner, R. a. Three-dimensional numerical modeling of a piled embankment. International Journal of Geomechanics, 9 (2009) 102- 112. doi:10.1061/(ASCE)1532-3641(2009)9:3(102).
[13] Naughton, P.J. 2007. The significance of critical height in the design of piled embankment. In Proceedings of Sessions of Geo-Denver 2007, Soil Improvement (GSP 172).
[14] Dias, D., & Simon, B. (2015). Spread foundations on rigid inclusions subjected to complex loading: Comparison of 3D numerical and simplified analytical modelling.
[15] Burtin, P., &Racinais, J. Embankment on Soft Soil Reinforced by CMC  Semi-Rigid Inclusions for the High-speed Railway SEA. Procedia engineering, 143 (2016) 355-362.
[16] Racinais, J. and Plomteux, C. (2011).  Design of slab-on-grades supported with soil reinforced by rigid inclusions. Retrieved from EYGEC 2011, Rotterdam, (The Netherlands).
[17] Liu, H., W. Charles, and K. Fei. Performance of a geogrid-reinforced and pile-supported highway embankment over soft clay: Case study. J. Geotech. Geoenviron. Eng. 133 (2007) 1483-1493. https://doi.org/10 .1061/(ASCE)1090-0241(2007)133:12(1483).
[18] Zhuang, Y., and K. Wang. Finite-element analysis on the effect of subsoil in reinforced piled embankments and comparison with theoretical method predictions. Int. J. Geomech. 16 (2016), 04016011. https://doi .org/10.1061/(ASCE)GM.1943-5622.0000628.
[19] Fattah, M. Y., Mohammed, H. A., & Hassan, H. A. Load transfer and arching analysis in reinforced embankment. Proceedings of the Institution of Civil Engineers-Structures and Buildings, 169 (2016) 797-808.
[20] Briancon L., Rapport N° 2.08.1.05. A.S.I.RI. - Tranche 2 - Thème 1 : rapport final. CNAM. (2008)
[21] Cambou, B., &Jafari, K. Modèle de comportement des sols non cohérents. Revue française de Géotechnique, 44 (1988) 43-55.
[22] Smith, M.E. 2005. Design of bridging layers in geosynthetic-reinforced column-supported embankments. PhD thesis, Department of Civil and Environmental Engineering, Virginia Polytechnic Institute and State University.
[23] Messioud, S., Okyay, U. S., Sbartai, B., & Dias, D. Dynamic response of pile reinforced soils and piled foundations. Geotechnical and Geological Engineering, 34 (2016) 789-805.
 
 
 
Engineering and Technology Journal
Volume 40, Issue 5
Civil Engineering
, 19 Articles
May 2022
Page 636-648
Files
Share
Export Citation
Statistics