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| Mapping Relationship between the Temperature and Longitudinal Displacement of Rails at the Transition between the Bridge and Tunnel |
| ZENG Zhi-ping1, LUO Jun1, RAO Hui-ming2, WU Zhi-peng1 |
| (1. Central South University, Changsha, Hunan 410075, China; 2. Beijing-Fujian-Jiangxi Passenger Dedicated Railway Co. Ltd, Fuzhou, Fujian 350013, China) |
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Abstract Abstract：Research purposes： The rails at the transition between bridge and tunnel will crawl longitudinally under the effect of temperature gradient, which influences the stability of CWR. Taking the rail at the temperature transition zone as the research object, the differential equation of rail displacement was established, the mapping relationship between rail temperature distribution and longitudinal displacement was deduced, and the law of influencing rail crawl of ballastless track was revealed in this paper. Research conclusions： (1) The longitudinal deformation and its range of nonlinear resistance model is much larger than the linear resistance model; for the rail maximum displacement, the non-linear distribution of rail temperature is 5.3%~38.6% higher than that of the linear distribution. It is suggested to consider the non-linearity of rail temperature and longitudinal resistance to accurately obtain the rail displacement at the transition. (2) When the rail temperature difference is constant, with the maximum temperature force gradient ratio k varying from 1.5 to 3.5, the largest rail longitudinal displacement increases only 7% when the transition zone length is 10 m but it increases 26.7% and 32.8% respectively when the length is 40 m and 50 m. Thus, more attention should be paid to the nonlinear rail temperature distribution for the transition with high rail temperature difference and long rail temperature transition zone. (3) The increase of limit resistance of fasteners will reduce the rail crawl significantly, but the influence degree is limited. The rail displacement decreases 40.8%~49.2% with the limit resistance varying from 6.5 kN/(m·rail) to 12 kN/(m·rail), but when the resistance changes from 24 kN/(m·rail) to 30 kN/(m ·rail), the slippage only is only 12.8%~24.4%. (4) The analytical expressions can accurately describe the mapping relationship between the parameters and the rail longitudinal displacement and provide useful references for further study of force characteristics of rail at the transition and improving the stability of CWR.
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Received: 20 October 2017
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| Cite this article: |
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ZENG Zhi-ping1,LUO Jun1,RAO Hui-ming2, et al. Mapping Relationship between the Temperature and Longitudinal Displacement of Rails at the Transition between the Bridge and Tunnel[J]. Journal of Railway Engineering Society, 2018, 35(1): 29-35.
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| URL: |
| https://tdgcxb.crec.cn/EN/ OR https://tdgcxb.crec.cn/EN/Y2018/V35/I1/29 |
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2018, Vol. 35 
