桥上有砟轨道无缝道岔非线性阻力及其影响分析

为了分析考虑阻力弹塑性变化的高速铁路桥上无缝道岔纵向力演变机理,使用试验与理论分析相结合的方法,全面考虑了道床纵向阻力的弹、塑性变化特征。进行扣件系统反复加卸载试验和有砟道床阻力测试,通过研究线路纵向阻力退化现象,分析其产生机理,并构建无缝道岔新型线路阻力本构模型。以高速铁路18号无缝道岔为例,在ANSYS中建立考虑边界效应的岔-桥-墩一体化模型,将试验所得参数与规范值进行仿真分析对比,深入分析考虑阻力弹塑性变化时对桥上无缝道岔受力及变形的影响。结果表明,当梁轨相对纵向位移较小时,使用规范规定的线路纵向阻力进行高速铁路桥上无缝道岔受力与变形分析,会使计算结果与实际相比普遍偏小。当出现阻力强化现象时,使用规范值进行无缝道岔的受力变形计算所得的结果偏于不安全。建议在实际工程中应尽量进行大量的试验分析,从而修正规范值。

Nonlinear Longitudinal Resistance Analysis of Ballast CWR Track Turnout on the Bridge

In order to analyze the longitudinal force evolution mechanism of welded turnout on high-speed railway bridges, the method of combining experiment with theoretical analysis is employed to address comprehensively the elastic-plastic change of resistance. The elastic and plastic characteristics of longitudinal resistance of the ballast and fasteners are considered. Based on repeated loading and unloading test of fastener system and ballast resistance, this paper studies the deterioration of longitudinal resistance of the track, analyzes its mechanism and constructs a new type of track resistance constitutive model for welded turnout. Taking the welded turnout of No.18 as an example, a turnout-bridge-pier integration model considering the boundary effect is established in ANSYS, the parameters of the experiment are compared with the standard values, and the influence of the resistance elastic-plastic change on the force and deformation of the welded turnout on the bridge is analyzed in detail. The results show that when the relative longitudinal displacement of beam and rail is small, and the force and deformation of seamless turnout on the bridge are analyzed by using the longitudinal resistance of the line specified in the specification, the calculation results are generally and comparatively smaller. When resistance intensification occurs, the results obtained from the calculation of the force deformation of seamless turnout by using the standard value are not safe. It is thus suggested that sufficient test and analysis should be carried out in practical engineering to revise the standard value.