桥上无缝线路钢轨伸缩附加力算法研究

Research on the Expansion Additional Force Algorithm of Continuously Welded Rail on Bridges

研究目的:目前的梁轨伸缩力算法较多使用常量阻力计算模型,当跨径很大时,有可能不存在有力学意义的解。为了得到准确的桥上无缝线路钢轨在温度作用下的伸缩力解析算法,解决桥梁温度跨度取值以及合理的纵向阻力选择问题,本文采用非线性纵向阻力模型,根据扣件进入塑性变形区的位置将无缝线路分成若干个区段,通过建立平衡微分方程组,求解得到钢轨位移及伸缩力。研究结论:(1)依照无缝线路规范设计条件,计算了不同纵向阻力、不同跨度桥梁上钢轨最大应力以及梁轨最大相对位移;(2)在不考虑制动力的情况下,可得出基于钢轨强度限值下不同纵向阻力对应的温度跨度限值;(3)以70 mm和90 mm作为断缝宽度限值,得出线路纵向阻力的最小取值分别为17 N/(mm·线)和13 N/(mm·线);(4)本文算法可为桥上无缝线路的桥梁温度跨度及线路纵向阻力的选择提供依据。

Research purposes： At present, the general resistance model is used to calculate the additional expansion force of rail. When the span is large, it is possible that there is no mechanical solution. In order to obtain an accurate analytical algorithm for the expansion force of the CWR on the bridge under temperature, provide a basis for selecting a reasonable bridge temperature span value and longitudinal resistance, a new algorithm is proposed. In this paper, the nonlinear longitudinal resistance model is used to separate the CWR into several sections according to the position where the fastener enters the plastic deformation zone. A set of equilibrium differential equations is set up to obtain the rail displacement and expansion force. Research conclusions： （ 1 ） According to the standard design condition of CWR, the maximum stress of rail and the maximum relative displacement between beam and rail under different longitudinal resistance are calculated. （2）Without considering the b based on the rail raking force, the temperature span limit corresponding to different longitudinal resistance is obtained strength limit. （ 3 ） Taking 70 mm and 90 mm as the fracture width limit, the minimum value of the line longitudinal resistance is 17 N/（ mm · line） and 13 N/（ mm · line）. （4） The conclusions of this paper can provide the basis for selecting the appropriate temperature span and longitudinal resistance of bridges.