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Keywords: railway track bed, finite element modelling, subgrade improvements, reinforcing geogrid, cyclic loading.

Summary

This paper deals with numerical and experimental investigations of a ballasted track under cyclic loading. The experimental part deals with measurement of settlements of different track bed designs under repetitive loading. The designs are tested in laboratory conditions in a small-scale box filled with ballast material reinforced with different types of geosynthetics. Different thickness of the ballast and sub-ballast layers are tested and the results in terms of measured settlements at different locations are compared with finite element models.

A new approach to model the reinforcing effect of geogrid is proposed and evaluated in the finite element analysis. The models are used to assess the performance of the geosynthetics in terms of settlement reduction. Experiments were performed up to 250,000 cycles whereas the results of the numerical models predict the behaviour up to 10,000,000 cycles. Finite element modelling enables rapid evaluation of various scenarios, e.g. the use of reinforcing geosynthetics in several layers. Extrapolation of the obtained results to a larger number of load cycles is also possible.

The application of finite element modelling to investigate the long-term reinforcing effect of different types of geosynthetics is presented. Several types of geosynthetics are considered with clear distinction between the geogrids and woven geosynthetics. The reinforcing effect of geogrid is modelled using a new approach which considers interaction between the geogrid material and ballast grains. The grains are considered to be reinforced by the geogrid material producing a layer of reinforced material. This is achieved through inserted boundary conditions (IBC). Settlement reduction is then calculated for each type of the geosynthetics.

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Front Page Browse CCP CSETS CTR IJRT Other Authors Search Purchase Guide FAQ Contact us	Civil-Comp Proceedings ISSN 1759-3433 CCP: 91 PROCEEDINGS OF THE TWELFTH INTERNATIONAL CONFERENCE ON CIVIL, STRUCTURAL AND ENVIRONMENTAL ENGINEERING COMPUTING Edited by: B.H.V. Topping, L.F. Costa Neves and R.C. Barros Paper 45 Behaviour of a Ballasted Track under Cyclic Loading: Numerical and Laboratory Investigations O. Jirousek¹, L. Hornicek², J. Jira³, J. Kunecky^1,3, D. Kytyr^1,3 and J. Vycichl^1,3 ¹Institute of Theoretical and Applied Mechanics AS CR, v.v.i, Czech Republic ²Faculty of Civil Engineering, CTU in Prague, Czech Republic ³Faculty of Transportation Sciences, CTU in Prague, Czech Republic doi:10.4203/ccp.91.45 purchase the full-text of this paper Full Bibliographic Reference for this paper O. Jirousek, L. Hornicek, J. Jira, J. Kunecky, D. Kytyr, J. Vycichl, "Behaviour of a Ballasted Track under Cyclic Loading: Numerical and Laboratory Investigations", in B.H.V. Topping, L.F. Costa Neves, R.C. Barros, (Editors), "Proceedings of the Twelfth International Conference on Civil, Structural and Environmental Engineering Computing", Civil-Comp Press, Stirlingshire, UK, Paper 45, 2009. doi:10.4203/ccp.91.45 Keywords: railway track bed, finite element modelling, subgrade improvements, reinforcing geogrid, cyclic loading. Summary This paper deals with numerical and experimental investigations of a ballasted track under cyclic loading. The experimental part deals with measurement of settlements of different track bed designs under repetitive loading. The designs are tested in laboratory conditions in a small-scale box filled with ballast material reinforced with different types of geosynthetics. Different thickness of the ballast and sub-ballast layers are tested and the results in terms of measured settlements at different locations are compared with finite element models. A new approach to model the reinforcing effect of geogrid is proposed and evaluated in the finite element analysis. The models are used to assess the performance of the geosynthetics in terms of settlement reduction. Experiments were performed up to 250,000 cycles whereas the results of the numerical models predict the behaviour up to 10,000,000 cycles. Finite element modelling enables rapid evaluation of various scenarios, e.g. the use of reinforcing geosynthetics in several layers. Extrapolation of the obtained results to a larger number of load cycles is also possible. The application of finite element modelling to investigate the long-term reinforcing effect of different types of geosynthetics is presented. Several types of geosynthetics are considered with clear distinction between the geogrids and woven geosynthetics. The reinforcing effect of geogrid is modelled using a new approach which considers interaction between the geogrid material and ballast grains. The grains are considered to be reinforced by the geogrid material producing a layer of reinforced material. This is achieved through inserted boundary conditions (IBC). Settlement reduction is then calculated for each type of the geosynthetics. purchase the full-text of this paper (price £20) go to the previous paper go to the next paper return to the table of contents return to the book description purchase this book (price £140 +P&P)
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