Critical loading for lateral buckling of continuous welded rail

The most significant differences between continuous welded rails (CWRs) and general split-type connectors are axial compression in the longitudinal direction, buckling stability and other issues generated under the influence of thermal effect. Under thermal effect, a dynamical behavior similar to that of a beam fixed on two sides occurs in the central locked area of the welded rail, as there is axial compression but no possibility of sliding. Continuous welded rails do not contract or expand, and are supported by the dynamical system made up of ballasts and rail clips. The rail-support system mentioned above has the features of non-uniform material distribution and uncertainty of construction quality. Due to these facts, the dynamics method based on the linear elastic hypothesis cannot correctly evaluate the rail's buckling conditions. This study is aimed at applying Finite Difference Method (FDM) and Monte Carlo Random Normal Variables Method to the analysis of welded rail's buckling behavior during the train's acceleration and deceleration, under thermal effect and uncertain factors of ballast and rail clips. The analysis result showed that buckling occurs under the combined effect of thermal effect and the train's deceleration force co-effect and the variance ratio of ballast and rail clips is over 0.85, or under the combined effect of thermal effect and the train's acceleration force when the variance ratio is over 0.88.