连续梁桥上无缝道岔断轨力计算分析

Calculation and Analysis of the Rupture Force of a Seamless Turnout on Continuous Beam Bridge

钢轨在桥梁上的最不利位置处会因强度不足而折断,并自断口处收缩,产生较大的位移量,致使列车经过断缝时产生巨大的冲击作用,严重时危及行车安全,因此,在进行连续梁桥上铺设无缝道岔的检算时,必须考虑断轨力的影响。以一组60kg/m钢轨18#可动心轨道岔为例,采用有限单元法,利用"岔-梁-墩-体化"模型,计算分析了连续梁桥在无缝道岔断轨力作用下桥梁与钢轨的受力和变形特征。结果表明,钢轨在岔前方向折断时桥墩所受纵向力要大于钢轨在岔后方向折断时的受力,道岔里轨的伸缩对桥墩受力起着主要作用;道岔前后不同位置钢轨折断对断轨力的计算结果影响较大,应代入最不利结果进行检算。

On the most disadvantaged position, arail will be fractured due to lack of strength, and then contract at the fracture, which will bring about a bigger displacement. There will be a strong impact when the trains pass the seam, and the impact can endanger traffic safety. So, the rupture force on the seamless turnout on a continuous beam bridge must be considered when calculating the turnout. An integral calculation model for the seamless turnout-beam-pier was established with the finite element method. Taking a size 18 swing nose turnout of 60 kg/m rail as an example, the forces and the characteristics of the deformation of the bridge and rail were analyzed. It turned out that the longitudinal force on the piers will be bigger when the seam appears behind the turnout than that ahead it and the contraction of the rail plays a major role in the forces on piers. Seam which appears at different places of the turnout will lead to various results at different degrees, so the most disadvantaged result should be adoDted.