遇水条件下无砟轨道扣件胶垫刚度的时变特性及其影响研究

连续强降雨条件下,轨下胶垫会出现长期泡在水中的情况。为研究该条件下无砟轨道轨下胶垫刚度的时变特性及其对轮轨系统的影响,以WJ-7A,WJ-7B型橡胶垫板为对象,通过设计室内原型试验,跟踪测试分析胶垫泡水后其刚度随服役时间的变化情况,并基于试验结果和轮轨动力学理论,分析胶垫刚度变化对轮轨动力响应的影响。研究结论:(1)WJ-7A型胶垫的遇水稳定性较差,泡水25 d后胶垫静刚度降低了22.21%,其中前5 d静刚度降低了18.83%;WJ-7B型胶垫的遇水稳定性较好,泡水25 d前后刚度变化率不超过3.91%;(2)泡水结束后,WJ-7A型胶垫的刚度恢复了88.9%,而WJ-7B型则继续表现出很好的稳定性,刚度值变化不大;(3)试验前后扣件刚度的变化引起的车体加速度、钢轨加速度、轮轨力及扣件力等响应的变化不大,但对钢轨位移影响较大,泡水后钢轨位移增幅达到13.71%。

Study on Time Variant Characteristics and Effects of Ballastless Track Fastening Pad Stiffness Subject to Water

Under the condition of continuous heavy rainfall,the rail pads are likely to be immerged in water for a long time. For the purpose of studying time variant characteristics of ballastless track rail pad stiffness under such a condition and its effects on wheel-rail system,an indoor prototype test is conducted on WJ-7A and WJ-7B rail pads to analysis the change of rail pad stiffness with the extension of service time. Based on the test results and the wheel-rail dynamics theory,the influence of the change of rail pad stiffness on wheel-rail response is analyzed. Research results show that:( 1) WJ-7A rail pad has poor stability subject to water and its static stiffness is decreased by 22. 21%,of which the static stiffness is reduced by 18. 83% after 25 days of immersion in water; while,the stability of WJ-7B rail pad is good and its stiffness change rate is less than 3. 91% after 25 days of immersion;( 2) at the end of water immersion,the stiffness recovery rate of WJ-7A rail pad is 88. 9%,while the stiffness of WJ-7B rail pad still remains good with little change of stiffness;(3) before and after the test,the change of the response of carbody acceleration,rail acceleration,wheel-rail force and fastening force caused by the change of rail pad stiffness is small,but its effect on rail displacement is obvious and the displacement may reach up to 13. 7%.