A generalized model for geosynthetic reinforced railway tracks resting on soft clays

Summary The present study pertains to the development of a foundation model for predicting the behavior of geosynthetic reinforcement railway track system rested on soft clay subgrade. The ballast and sub-ballast layers have been idealized by Pasternak shear layer. The geosynthetic layer is represented by a stretched rough elastic membrane. Burger model has been used to characterize the soft clay subgrade. Numerical solutions have been obtained by adopting the finite difference scheme combined with non-dimensioning the governing equations of the proposed model. The results confirm that the present model is quite capable of predicting the time-dependent settlement response of geosynthetic reinforcement railway track system placed on soft clay subgrade. The surface settlement profile and mobilized tensile load of geosynthetics has been evaluated by considering variation in the wheel load, sleeper width, thickness of ballast and sub-ballast layers and shear modulus of ballast and sub-ballast layers. It has been observed that an increase in the sleeper width by 24% results in the reduction in central settlement and mobilized tensile load by 6.5% and 20.1%, respectively. It was found that with a 50% increase in the thickness of the ballast layer, the central settlement has decreased by 7.3% and the mobilized tension at the zone of maximum curvature has increased by 24.6%. However, with an increase in the thickness of the sub-ballast layer, a considerable reduction in both central settlement and the mobilization of tension on geosynthetic has been noticed. The pattern of variation of settlement and mobilized tension for an increase in the shear modulus of ballast and sub-ballast material was found to be almost similar. Copyright © 2014 John Wiley & Sons, Ltd.

[1]  P. K. Basudhar,et al.  Parameter estimation of four-parameter viscoelastic Burger model by inverse analysis: case studies of four oil-refineries , 2012 .

[2]  Sanjay Kumar Shukla,et al.  A generalized mechanical model for geosynthetic-reinforced foundation soil , 1994 .

[3]  P. K. Basudhar,et al.  Flexural response of surface strip footings resting on reinforced viscoelastic foundation beds , 2011 .

[4]  Arnold D. Kerr,et al.  A study of a new foundation model , 1965 .

[5]  G. Raymond.  Reinforced ballast behaviour subjected to repeated load , 2002 .

[6]  Kousik Deb,et al.  Generalized Model for Geosynthetic-Reinforced Granular Fill-Soft Soil with Stone Columns , 2007 .

[7]  I. Alpan,et al.  THE EMPIRICAL EVALUATION OF THE COEFFICIENT K0 AND K0R , 1967 .

[8]  Colin J F P Jones,et al.  When the Bending Stiffness of Geosynthetic Reinforcement is Important , 2001 .

[9]  Priti Maheshwari,et al.  Analysis of beams on reinforced granular beds , 2004 .

[10]  Ennio M. Palmeira,et al.  Soil–geosynthetic interaction: Modelling and analysis ☆ , 2009 .

[11]  Kousik Deb,et al.  Modeling of granular bed‐stone column‐improved soft soil , 2008 .

[12]  Sanjay Kumar Shukla,et al.  Time-dependent settlement analysis of a geosynthetic-reinforced soil , 2003 .

[13]  Mostafa A. El Sawwaf,et al.  Behavior of strip footing on geogrid-reinforced sand over a soft clay slope , 2007 .

[14]  B. Viswanadham,et al.  Numerical Simulation of Geogrid-Reinforced Soil Barriers Subjected to Differential Settlements , 2015 .

[15]  Dimitris L. Karabalis,et al.  Dynamic 3‐D soil–railway track interaction by BEM–FEM , 1995 .

[16]  Sanjay Nimbalkar,et al.  The Behaviour of Ballasted Track Foundations: Track Drainage and Geosynthetic Reinforcement , 2010 .

[17]  Anirban Dhar,et al.  Parameter Estimation for a System of Beams Resting on Stone Column-Reinforced Soft Soil , 2013 .

[18]  J. Horvath.  Subgrade Models for Soil-Structure Interaction Analysis , 1989 .