地铁车辆段轨枕垫与道砟垫组合减振效果研究

Combined vibration reduction effect of sleeper pad and ballast pad in metro depot

为了研究因地铁列车通过车辆段道岔区产生的剧烈轮轨相互作用而诱发的振动超限问题,依靠轨枕垫和道砟垫良好的弹性和阻尼特性,在道岔区敷设轨枕垫和道砟垫,为实现道岔刚度均匀化和缓解振动超限问题提供了有效方法。首先,基于道岔刚度均匀化原则和道岔钢轨-岔枕有限元模型,对轨枕垫刚度均匀化进行设计,探讨轨枕垫刚度均匀化前后、轨枕垫布置范围以及扣件刚度对道岔刚度均匀化的影响,结合钢轨纵向挠度变化率限值,明确道岔刚度均匀化初步设计方案;然后,建立车辆-道岔-有砟道床耦合动力学模型,并计算道岔刚度均匀化前后的试验落轴高度,采用室内落轴试验评价轨枕垫与道砟垫组合措施的减振效果,明确道岔刚度均匀化最终设计方案;最后,开展现场实测试验验证道岔刚度均匀化后的减振效果。研究结果表明:在道岔区铺设轨枕垫有助于改善道岔刚度沿纵向不均匀的情况;建议在非辙叉区与辙叉区采用分区设计,以满足道岔区的钢轨纵向挠度变化率限值和减振效果需求;扣件刚度对道岔辙叉区刚度均匀化的影响不显著;采用道砟垫时,Z振级最大插入损失为9 dB,采用轨枕垫与道砟垫组合措施的减振效果能达到15 dB;现场实测结果说明轨枕垫与道砟垫的组合减振方式能够达到预期的减振效果。

Here,to study the problem of excessive vibration induced by severe wheel-rail interaction of subway trains passing through turnout area of vehicle depot,relying on good elasticity and damping characteristics of sleeper pad and ballast pad,laying sleeper pads and ballast pads in turnout area could provide an effective method to realize homogenization of turnout stiffness,and alleviate the problem of vibration exceeding limit.Based on the principle of turnout stiffness homogenization and turnout rail-turnout sleeper finite element model,the stiffness homogenization of sleeper pads was designed,effects of sleeper pad stiffness before and after its stiffness homogenization,sleeper pad layout range and fastener stiffness on turnout stiffness homogenization were explored,and the preliminary design scheme of turnout stiffness homogenization was clarified by combining the limit of longitudinal deflection rate of rail.Then,a vehicle-turnout-ballast bed coupled dynamic model was established,and test axle drop heights before and after turnout stiffness homogenization were calculated.Indoor axle drop tests were used to evaluate the vibration reduction effect of combined measures of sleeper pad and ballast pad,and clarify the final design scheme for homogenization of turnout stiffness.Finally,on-site tests were conducted to verify the vibration reduction effect after homogenization of turnout stiffness.The study results showed that laying sleeper pads in turnout area can help improving longitudinal unevenness of turnout stiffness;it is recommended to adopt zoning design for non-frog area and frog area to meet requirements of rail longitudinal deflection rate limit and vibration reduction effect in turnout area;effects of fastener stiffness on the homogenization of turnout stiffness in frog area are not significant;when using ballast pad,the maximum insertion loss of Z-vibration level is about 9 dB,and the vibration reduction effect of using combined measures of sleeper pad and ballast pad can reach about 15 dB;on-site test results reveal the combination of sleeper pad and ballast pad being able to achieve the expected vibration reduction effect.