Theoretical And Experimental Analysis Of250M Radius Curve Continuous Welded Rail At Jing-Cheng Railway Line

Jing-Cheng railway line was located in a mountain area, there are some curves with250meter radius in this line, to solve joints’ disease, swing of locomotive, considerable change of geometric dimensioning, hard retain of curve type, high cost of maintain and difficulty of driving, these were advised to be built as continuously welded rail track. However, the research for continuously welded rail with250meters radius is quite few, a lot of problems about small-radius continuously welded rail are to be solved, and technical research is still needed for study feasibility of laying250meters continuously welded rail.Based on small-radius curve in Jing-Cheng railway line, finite element model of continuously welded rail is built in this thesis, which included one-way curve and reverse curve contained the easement curve and straight line. Also, finite element model of continuously welded rail with curve initial deflection and typical strengthening measures is also presented. Stress and deformation law is studied, the difference between250meters continuously welded rail and the one with300meters is compared. The effect of different strengthen measures on the stability of small-radius continuously welded rail is studied, which is analyzed with the combination of experiment data. Main conclusions are as follows:(1) It is feasible to lay out250meters radius continuously welded rail under chosen track structure condition, its stability and strength can maintain with low temperature in winter and high temperature in summer(2) The rail lateral move of curve continuously welded rail can happen at the first period of rail temperature change, compared with continuously welded rail in straight line, the ballast resistance can be damaged more easily, the stress and deformation law are similar in circular curve of one-way and reverse curve.(3) Under the normal ballast resistance, the stability parameter values are close of curve with250and300meters radius. But, with decrease of track bed resistance, the difference becomes larger, therefore, it should be noticed that the normal track bed resistance must be maintained, especially the lateral resistance.(4) With smooth curve line and normal ballast resistance, ground anchor rod is not necessary, but, it can play a significant role when resistance decreases, so the anchor rod can be set up every10meters or5meters, which according to the safety requirement and rail temperature range. Gauge pull rod has a little effect on enhancing the stability of railway lines. With initial irregularity of railway lines, the effect of ground anchor rod every20meters and10meters on controlling rail maximum lateral displacement is not good. The allowable arise of temperature can increase by4℃when laying anchor rod every5meters on curve.(5) Railway line shape is good at most section from observation data, curve is smooth, and several measure data of20meters chord length exceeds limited value. Rail creep displacement doesn’t exceed limited value. It’s found that most results match the Ⅱ level comfort standards from dynamic test of track inspection car.