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Response of Multilayer Foundation System beneath Railway Track under Cyclic Loading |
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| Authors: | Deepankar Choudhury Rajeev Kumar Bharti Siddharth Chauhan Buddhima Indraratna |
| Affiliation: | 1Associate Professor, Dept. of Civil Engineering, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India (corresponding author). E-mail: dc@civil.iitb.ac.in 2Postgraduate Student, Dept. of Civil Engineering, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India. E-mail: rajbharti@iitb.ac.in 3Postgraduate Student, Dept. of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139-4307; formerly, Undergraduate Student, Dept. of Civil Engineering, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India. E-mail: siddhu@MIT.EDU 4Professor, Dept. of Civil and Mining Engineering, Univ. of Wollongong, North-field Ave., Wollongong, New South Wales, Australia 2522. E-mail: indra@uow.edu.au |
| Abstract: | For an efficient and economical design of a railway track system, it is necessary to understand the behavior of each track component with special reference to ballast and subgrade, which play a pivotal role in distributing the large, cyclic wheel loads longitudinally, laterally, and vertically away from the wheel contact area on the rail surface to the underlying soil strata. This paper presents an analytical model of a track-ballast-subgrade system with different formation soils such as dense uniform sand, stiff clay, loose sand, and soft clay modeled by using a mass-spring dashpot system with two degrees of freedom. This represents the varying energy distribution through ballast and subgrade in the vertical direction. Results are presented in the form of time-displacement response profiles for both the ballast and subgrade layers. In addition, the magnification factors for displacements with variation in subgrade soils for cyclic loading frequencies are reported. It is observed that the results obtained from the present analysis follow the experimentally observed trends already available in the literature. |
| Keywords: | Railroad tracks Dynamic models Cyclic loads Subgrades Ballast Displacement Foundations |