绿化埋入式有轨电车轨道弹条松动及失效对钢轨轨头横移的影响
沈继强
Influence of Fastener Clip Loosening and Failure on Rail Head Lateral Displacement in Green Belt Embedded Tram Tracks
SHEN Jiqiang
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作者信息:上海市城市建设设计研究总院(集团)有限公司， 200135， 上海
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Affiliation:Shanghai Urban Construction Design & Research Institute (Group) Co., Ltd., 200135, Shanghai, China
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关键词:
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Key words:
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DOI:10.16037/j.1007-869x.20245950
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中图分类号/CLCN:U213.2+13
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栏目/Col:土建工程
摘要:
［目的］对于绿化埋入式轨道，由于不能直接观察其扣件状态，并且仅对钢轨几何尺寸进行测量也不能直观反映扣件弹条的松动和失效情况，因此不能及时有效维护扣件，造成轨道几何状态恶化，故应研究绿化埋入式有轨电车轨道弹条松动及失效对钢轨轨头横移的影响。［方法］利用有限元法建立钢轨倾覆分析模型，钢轨采用实体单元，扣件弹条、弹性垫板及横向支撑采用非线性弹簧单元，通过控制弹条扣压弹簧的下压位移模拟扣压力的变化，将轮轨力分为垂向力和横向力，采用集中力加载。针对模型，测试在不同弹条松弛量、不同弹条失效个数时，在双侧弹条失效、内侧弹条失效、外侧弹条失效及轨距块脱落情况下，钢轨轨头的横移变化、钢轨与弹性垫板的接触长度变化情况。［结果及结论］较小轮轨横向力作用下，弹条松弛量、轨距块脱落和无脱落双侧弹条失效个数对钢轨轨头横移变化影响较小。轮轨横向力变大时，钢轨轨头横移量随弹条松弛量变大而增大，但变化趋势较缓；钢轨轨头横移量随双侧弹条失效个数增多而变大。同等条件下对比轨距块脱落和无脱落工况，二者钢轨倾覆角弧度接近，钢轨轨底横移导致钢轨轨头横移量增大。弹条内侧失效时，钢轨轨头横移量随弹条失效个数增多而变大；弹条外侧失效时则相反。
Abstracts:
［Objective］ In green belt embedded tracks, the condition of fasteners cannot be directly observed, and measurements of rail geometry alone cannot intuitively reflect the fastener clips loosening or failure. As a result, timely and effective maintenance may not be implemented, leading to degradation of track alignment conditions. Therefore, it is necessary to study the influence of fastener clip loosening and failure on rail head lateral displacement in green belt embedded tram tracks. ［Method］ A rail overturning analysis model is established using finite element method. The rail is modeled with solid elements, while fastener clips, elastic baseplates, and lateral supports are modeled with nonlinear spring elements. The variation of clamping force is simulated by controlling the downward displacement of the spring, representing the clip pressure. The wheel-rail forces are divided into vertical and lateral components, applied as concentrated loads. The model is used to evaluate changes in rail head lateral displacement and contact length between the rail and elastic baseplate under various conditions, such as simultaneous failure of clips on both sides, failure on the inner side only, failure on the outer side only, and in the case of track gauge block detachment, under different amounts of clip loosening and varying numbers of failed clips. ［Result & Conclusion］ Under smaller wheel-rail lateral forces, the degree of clip loosening, the track gauge block detachment and the number of failed clips on both sides without detachment have minimal impact on rail head lateral displacement. When lateral forces increase, rail head lateral displacement will increase with greater clip loosening, though the trend remains gradual. Rail head lateral displacement also enhances as the number of failed dual-side clips increases. Under the same conditions, comparison between scenarios with and without track gauge block detachment shows similar rail overturning angles, but the lateral displacement of the rail base leads to an increased rail head displacement. When clips fail on the inner side, rail head displacement increases with more failed clips; the opposite effect is observed when clips fail on the outer side.
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