Analytical Solution to Analyze LTP on Column-Improved Soft Soil Considering Soil Nonlinearity
Publication: International Journal of Geomechanics
Volume 17, Issue 3
Abstract
In this paper, a mechanical model to idealize the load-settlement response of the load transfer platform (LTP) on column-improved soft soil is proposed. This model simultaneously considers the nonlinear and time-dependent stress-strain behavior of soft soil and the negligible tensile strength of the granular material in LTP. The reinforced Timoshenko beam is adopted to model LTP to consider the shear and flexural deformations. Soft soil is idealized by a spring-dashpot system that includes nonlinear and time-dependent behaviors. The columns and geosynthetics are modeled with linear Winkler springs in the applied range of stresses and rough elastic membrane, respectively. The response function of LTP has been derived for distributed pressure loading in the plane strain condition. The principle of superposition is used to solve the fourth-order differential equations. Parametric studies indicate that the spacing of columns, thickness of LTP, degree of consolidation of the soft soil, and tensile stiffness of the geosynthetics significantly affect the behavior of LTP. This study also evaluates the accuracy of using reinforced Timoshenko theory by comparing the results with Pasternak and Euler-Bernoulli theories.
Get full access to this article
View all available purchase options and get full access to this article.
Acknowledgments
The authors would like to acknowledge the financial support received from Roads and Maritime Services (RMS), SMEC Australia, Fulton Hogan, and Menard-Bachy. A special thanks to A. H. M. Kamruzzaman from RMS for his valuable comments at different stages of the project.
References
Abusharar, S. W., Zheng, J. J., Chen, B. G., and Yin, J. H. (2009). “A simplified method for analysis of a piled embankment reinforced with geosynthetics.” Geotext. Geomembr., 27(1), 39–52.
Azari, B., Fatahi, B., and Khabbaz, H. (2016). “Assessment of the elastic-viscoplastic behavior of soft soils improved with vertical drains capturing reduced shear strength of a disturbed zone.” Int. J. Geomech., B4014001.
Bhasi, A., and Rajagopal, K. (2015). “Geosynthetic-reinforced piled embankments: Comparison of numerical and analytical methods.” Int. J. Geomech., 04014074.
Chandra, S., Madhav, M. R., and Iyengar, N. (1987). “A new model for nonlinear subgrades.” Math. Modell., 8, 513–518.
Cowper, G. (1966). “The shear coefficient in Timoshenko’s beam theory.” J. Appl. Mech., 33(2), 335–340.
Deb, K. (2010). “A mathematical model to study the soil arching effect in stone column-supported embankment resting on soft foundation soil.” Appl. Math. Modell., 34(12), 3871–3883.
Deb, K., Basudhar, P., and Chandra, S. (2007). “Generalized model for geosynthetic-reinforced granular fill-soft soil with stone columns.” Int. J. Geomech., 266–276.
Fatahi, B., and Tabatabaiefar, S. H. R. (2014). “Fully nonlinear versus equivalent linear computation method for seismic analysis of midrise buildings on soft soils.” Int. J. Geomech., 04014016.
Filonenko-Borodich, M. M. (1940). “Some approximate theories of the elastic foundation.” Uchenyie Zapiski Moskovskogo Gosudarstvennogo Universiteta Mekhanica, 46, 3–18.
Fulton Hogan. (2015). “Gerringong upgrade project, Mount Pleasant to Toolijooa road.” ⟨http://www.fultonhogan.com⟩ (July 7, 2016).
Graham, J., Crooks, J., and Bell, A. L. (1983). “Time effects on the stress-strain behaviour of natural soft clays.” Géotechnique, 33(3), 327–340.
Gudehus, G., Goldscheider, M., and Winter, H. (1977). “Mechanical properties of sand and clay and numerical integration methods: some sources of errors and bounds of accuracy.” Finite Elem. Geomech., 121–150.
Han, J., and Gabr, M. (2002). “Numerical analysis of geosynthetic-reinforced and pile-supported earth platforms over soft soil.” J. Geotech. Geoenviron. Eng., 44–53.
Hokmabadi, A. S., and Fatahi, B. (2015). “Influence of foundation type on seismic performance of buildings considering soil–structure interaction.” Int. J. Struct. Stab. Dyn., 16, 1550043.
Horvath, J., and Colasanti, R. (2011). “Practical subgrade model for improved soil-structure interaction analysis: model development.” Int. J. Geomech., 59–64.
Huang, J., and Han, J. (2010). “Two-dimensional parametric study of geosynthetic-reinforced column-supported embankments by coupled hydraulic and mechanical modeling.” Comput. Geotech., 37(5), 638–648.
Hutchinson, J. R. (2001). “Shear coefficients for Timoshenko beam theory.” J. Appl. Mech., 68(1), 87.
Kravtchenko, J., and Sirieys, P. (1966). Rheology and soil mechanics. International symposium on rheology and soil mechanics, grenoble, Springer, Berlin.
Le, T. M., and Fatahi, B. (2016). “Trust-region reflective optimisation to obtain soil visco-plastic properties.” Eng. Comput., 33(2), 410–442.
Le, T. M., Fatahi, B., and Khabbaz, H. (2015). “Numerical optimisation to obtain elastic viscoplastic model parameters for soft clay.” Int. J. Plast., 65, 1–21.
Madhav, M. R., and Poorooshasb, H. B. (1988). “A new model for geosynthetic reinforced soil.” Comput. Geotech., 6(4), 277–290.
Maheshwari, P., and Khatri, S. (2013). “Response of infinite beams on geosynthetic-reinforced granular bed over soft soil with stone columns under moving loads.” Int. J. Geomech., 713–728.
Maheshwari, P., and Viladkar, M. N. (2009). “A mathematical model for beams on geosynthetic reinforced earth beds under strip loading.” Appl. Math. Modell., 33(4), 1803–1814.
MATLAB R2014b [Computer software]. Matrix Laboratory Software, MathWorks, Natick, MA.
McCormac, J. C., and Brown, R. H. (2009). Design of reinforced concrete, John Wiley & Sons, Hoboken, NJ.
Nguyen, L., and Fatahi, B. (2016). “Behaviour of clay treated with cement & fibre while capturing cementation degradation and fibre failure–C3F model.” Int. J. Plast., 81, 168–195.
Parry, R. H. G. (1972). Stress-strain behaviour of soils, G. T. Foulis, Henley-on-Thames, U.K.
Parsa-Pajouh, A., Fatahi, B., and Khabbaz, H. (2016). “Experimental and numerical investigations to evaluate two-dimensional modeling of vertical drain–assisted preloading.” Int. J. Geomech., B4015003.
Pasternak, P. L. (1954). On a new method of analysis of an elastic foundation by means of two constants, Gosudarstvennoe Izdatelstvo Literaturi po Stroitelstvu i Arkhitekture, Moscow (in Russian).
Selvadurai, A. P. (1979). Elastic analysis of soil-foundation interaction, Elsevier Scientific, Amsterdam, Netherlands.
Tan, S. A., Tjahyono, S., and Oo, K. (2008). “Simplified plane-strain modeling of stone-column reinforced ground.” J. Geotech.Geoenviron. Eng., 185–194.
Terzaghi, K. (1943). Theoretical soil mechanics, John Wiley and Sons, New York.
Timoshenko, S. P. (1921). “On the correction for shear of the differential equation for transverse vibrations of prismatic bars.” Philos. Mag., 41(245), 744–746.
Timoshenko, S. P., and Gere, J. M. (1961). Theory of elastic stability, McGraw-Hill Kogakusha, Tokyo.
Wang, C. (1995). “Timoshenko beam-bending solutions in terms of Euler-Bernoulli solutions.” J. Eng. Mech., 763–765.
Winkler, E. (1867). Die Lehre von der Elasticitaet und Festigkeit: Mit besonderer Rücksicht auf ihre Anwendung in der Technik für polytechnische Schulen, Dominicus, Prague, Czech Republic (in German).
Yin, J. H. (1999). “Properties and behaviour of Hong Kong marine deposits with different clay contents.” Can. Geotech. J., 36(6), 1085–1095.
Yin, J. H. (2000a). “Closed-form solution of reinforced Timoshenko beam on elastic foundation.” J. Eng. Mech., 868–874.
Yin, J. H. (2000b). “Comparative modeling study of reonforced beam on elastic foundation.” J. Geotech. Geoenviron. Eng., 265–271.
Information & Authors
Information
Published In
International Journal of Geomechanics
Volume 17 • Issue 3 • March 2017
Copyright
© 2016 American Society of Civil Engineers.
History
Received: Jan 26, 2016
Accepted: May 31, 2016
Published online: Aug 26, 2016
Discussion open until: Jan 26, 2017
Published in print: Mar 1, 2017
Authors
Metrics & Citations
Metrics
Citations
Download citation
If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download.