城市轨道交通线路钢轨剥落掉块分析与防治措施

Analysis and Prevention of Rail Spalling in Urban Rail Transit

对苏州轨道交通2号线钢轨剥落掉块地段进行调查研究,了解了钢轨剥落掉块的具体情况与原因。通过现场轨底坡调整实验与有限元计算可知,在小半径曲线地段将上、下股轨底坡均由1∶40调至1∶20后,曲线上股钢轨光带由内侧转移至钢轨顶部中间区域;轨底坡调整后,钢轨受力情况由偏荷载变成正荷载,其应力与变形量均减小;轨底坡调整前钢轨应力集中在钢轨内侧轨头弧度位置,与现场剥落掉块处相吻合,轨底坡调整后钢轨应力基本均匀分布于整个轨头,避开了现场剥落掉块处。因此建议在城市轨道交通钢轨剥落掉块预防整治时可以考虑在小半径(半径小于400m)曲线地段将轨底坡设置为1∶20,该措施可减少轮轨非正常接触,延缓剥落掉块的发展。

The rail spalling and falling sections on Suzhou rail transit Line 2 are investigated, the specific situations and causes of rail spalling are studied. Through the bottom slope adjustment experiment on the spot and finite element calculation, it is found out that when the rail bottom slope is adjusted from 1 ∶40 to 1 ∶20 in small radius curve, the rail light band will transfer from rail inside area to the top middle area. At the same time, when the rail load is adjusted from partial load to positive one, the stress and deformation will decrease. Previous to rail base slope adjustment, the stress is concentrated of rail inside area, coincide with the rail falling site. After rail base slope adjustment, the stress that concentrated on rail inside will turn to be an evenly distribution, thus keeping away from the rail spalling section. So, it is suggested that the rail bottom slope should be set to 1 ∶20 in the small radius curve （radius less than 400m）, this method can reduce the abnormal contact between wheel and rail and delay the development of spalling for the prevention and regulation of urban rail transit.