重载铁路道砟清洁度对聚氨酯固化道床力学性能的影响

Impact of Ballast Cleanliness on Mechanical Properties of Polyurethane Solidified Ballasted Track Bed in Heavy Haul Railway

道砟颗粒表面清洁度分别取0.17%、0.50%、0.70%、1.00%,通过室内实尺模型疲劳试验,分析500万次疲劳荷载作用下聚氨酯固化道床沉降、道床静态模量的变化规律以及轨枕与道床的黏结性能。结果表明,当道砟清洁度超过0.50%后,聚氨酯固化道床沉降明显增大,道床静态模量无明显变化,轨枕与道床黏结性能变差。建议聚氨酯固化道床施工时,在道砟装载、运输过程中采取措施防止道砟二次污染,上砟整道时采取少捣多稳工艺,确保固化道床浇注前道砟清洁度在0.50%以内。

This study examines the cleanliness of ballast at various levels(0.17%,0.50%,0.70%,and 1.00%)and their impact on the performance of polyurethane solidified track bed through indoor full-scale fatigue tests conducted over 5 million cycles.The research analyzes the settlement of the polyurethane solidified ballasted track bed,changes in the track bed’s static modulus,and the bonding performance between sleepers and the track bed under these conditions.The findings reveal that once the track ballast cleanliness surpasses 0.50%,there is a significant increase in settlement of the polyurethane solidified track bed.However,the static modulus of the track bed remains relatively stable,while the bond between sleepers and the track bed weakens.Based on these results,it is recommended that preventive measures be taken during ballast loading and transportation to avoid secondary contamination.Furthermore,employing construction techniques that minimize tamping and ensure stability during ballast laying is advised to maintain ballast cleanliness below 0.50%before pouring the polyurethane.