Comparison between Theoretical and Experimental Behavior of Shallow Foundation in Cohesive Soil

Al-Dawoodi, Baraa A.; Waheed, Mohaned Q.; Rahil, Falah H.

doi:10.30684/etj.v39i12.2124

	Comparison between Theoretical and Experimental Behavior of Shallow Foundation in Cohesive Soil
Engineering and Technology Journal
Article 21, Volume 39, Issue 12, December 2021, Pages 1911-1918 PDF (812.15 K)
Document Type: Research Paper
DOI: 10.30684/etj.v39i12.2124
Authors
Baraa A. Al-Dawoodi^* ; Mohaned Q. Waheed; Falah H. Rahil
Civil Engineering Dept., University of Technology -Iraq, Alsina’a street, 10066 Baghdad, Iraq.
Abstract
This paper discusses a finite element analysis of shallow footing subjected to axial loading rested on different types of cohesive soil by using a computer program called PLAXIS-3D (V.20) software. The behavior of cohesive soil is simulated using several constitutive models (Mohr-Coulomb model, Hardening soil model, and Hardening soil with small strain stiffness model in order to find the best match between theoretical and experimental results).Two cases are considered square and rectangle. Moreover, some parameters that affect the load settlement relation curve; such as internal friction angle and soil modulus elasticity were investigated. It was found that the simulation by the Hardening soil model with small strain stiffness gives better results in both cases of the square and rectangle (C=25) and square footing (C=70). It was also observed that increasing the foundation width led to increases in bearing capacity, however, there was an increase of bearing capacity to about (9.45 %) for an increase in footing width of (6.25), so it was about (17%) for (12.5). For square footing in stiff clayey soil, the bearing capacity of the soil increases to about (23%) when the range of the modules of elasticity of soil increases from (10000 to 30000KN/m²).
Highlights
Clay with (cu) of 25 and 70 kPa, simulation by the HSs model gave the best results. Footing capacity by MC model in stiff clay increased with increasing friction angle. Increase soil modulus from (10 to 30 MPa) cause increase in bearing capacity 23 %. MC matches curve at elastic zone then over predicts at the final stage of loading.
Keywords
Shallow foundation; Cohesive soil; finite element; PLAXIS 3D 2020 software

Full Text
[1] A. W. Strahler. Bearing capacity and immediate settlement of shallow foundations on clay.‏M.Sc. Thesis,Oregon State University (2012). [2] P.W. Roscoe, A.N. Schofield, and C.P. Wroth, PLAXIS manual. Version 8. Rotterdam: Balkema. . On the yielding of soils. Geotechnique, (1958), 22--52. [3] STRAUS-7. Guidaall’uso di Straus-7. Concezione e sviluppo. Sydney, Australia: 1999G+D Computing. FLAC-3D. [4] FLAC-3D,. FLAC: Fast Lagrangian Analysis of Continua. Minneapolis, MN: 1996 Itasca Consulting Group. [5] F. Darve. Incrementally non-linear constitutive relationship. In: F. Darve, ed. Geomaterials: 1990, constitutive equations and modelling., 213--238. [6] R. Chambon, Chambon. Uniqueness, second order work and bifurcation in hypoplasticity. In: D. Kolymbas, ed. Constitutive modeling including development in hypoplasticity. New York: Springer, Chambon, 147--165. [7] Y.F. Dafalias, and M.T. Manzari. Simple plasticity sand model accounting for fabric changes effects. Journal of engineering mechanics ASCE, 130 (2004) 622--634. [8] D.Muir Wood. Geotechnical modelling.Taylor & Francis Group, London: Spon.( 2004) [9] M. Y. Fattah, F. A.Salman& B. J. Nareeman.Numerical simulation of triaxial test in clayey soil using different constitutive relations. In Advanced Materials Research. 243 (2011) 2973-2977 Trans Tech Publications Ltd.‏ [10] M. Ornek,. M., Laman, A., Demir, & A. Yildiz, Numerical analysis of circular footings on natural clay stabilized with a granular fill. Acta geotechnicaslovenica, 9 (2012) 61-75. [11] R. F. IbrahimA.Laboratory And Numerical Study On Natural Iraqi Soft Clayey Soil (Master dissertation, University of Technology).‏ , (2014). [12] S. A.,Naeini, & E .Taherabadi,. Numerical and theoretical study of plate load test to define coefficient of subgrade reaction. Journal of Geotechnical and Transportation Engineering, 1(2), (2015). [13] M. Q.Waheed& N. M.Asmael. Parametric study of shallow foundation bearing capacity in clayey soil‏International Journal of Civil Engineering and Technology (IJCIET 9 (2018) 10. [14] .M.Q .Waheed&Moutaz.N.Asmsil .Study simulation of shallow foundation behavior using different finite element models. Journal of Advanced Civil Engineering Practice and Research · 8 (2019) [15] PLAXIS 3D Tutorial Manual Connect Edition V20. [16] Plaxis 3d Reference Manual Connect Edition V20. [17] S.S. Rao, the finite element method in engineering, fourth edition, Elsevier Science & Technology Books , (2004)76-68 . [18] M. Y. Fattah, F. A. Salman, & B. J. Norseman .Numerical simulation of triaxial test in clayey soil using different constitutive relations. In Advanced Materials Research 243 (2011) 2973-2977Trans Tech Publications. [19] M. Fattah, W. Al-Baghdadi, M.Omar, & A. Shanableh. Analysis of strip footings resting on reinforced granular trench by the finite element method. International Journal of Geotechnical Engineering, 4(2010) 471-482.‏ [20] F. H. Rahil. Improvement of soft clay underneath a railway track model using stone columns technique (Doctoral dissertation, Ph. D. Thesis, University of Technology, Iraq.(2007). [21] R. B. J. Brinkgreve, E. Engine and W. M. Wolf's .Praxis 3D 2020 user manual. Plaxisbv, Delft. (2020).
References
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