铁道建筑

为研究营业线换轨大修施工一线待换长钢轨的稳定性，本文利用有限元法模拟不同长度的待换长钢轨受温度力、与石砟道床的摩擦阻力、加固杆横向约束力的共同作用，研究其横向位移随温升的发展变化规律。结果表明：待换长钢轨最长稳定单元为1 200 m，该长度的长钢轨在温升达到40℃时能保持相对稳定状态，不会引起局部大变形；温升超过8℃后，长钢轨横向变形随着温升快速发展，内部应力在变形处得到释放。现场应用中，采用不大于1 200 m的换轨单元可不进行人工放散应力作业，避免点外上道的安全风险；换轨单元长度超过1 200 m时，温升每提高8℃进行一次应力放散作业。

In order to study the stability of long rails ready for service on the construction frontline of the business line track replacement overhaul, this paper used finite element method to simulate the combined effects of temperature force, frictional resistance with the stone ballast bed, and transverse constraint force of the reinforcement rod on long rails ready for service with different lengths, and studied the development and variation of their lateral displacement with temperature rise. The results show that the longest stable unit of the long rails ready for service is 1 200 m, and long rail with this length can maintain a relatively stable state when the temperature rise reaches 40 ℃, without causing local large deformation. After the temperature rise exceeds 8 ℃, the transverse deformation of the long rail develops rapidly with the temperature rise, and the internal stress is released at the deformation site. In on-site applications, the use of track changing units with a length of not more than 1 200 m eliminates the need for manual stress relief operations, thus avoiding safety risks of going onto the track outside the designated point. When the length of the track changing unit exceeds 1 200 m, stress relief operations should be carried out when the temperature rise increases every 8 ℃.