中文摘要：

大机捣固是有砟线路养护维修作业的主要工作之一。基于在决定捣固维修作业时机方面很少考虑捣固作业成本，提出综合评价指数的捣固维修作业时机决策方法。以捣固作业后的轨道质量指数TQI表征列车运行品质，以捣固周期间接衡量捣固作业成本，综合考虑列车运行品质与捣固作业成本2个方面因素评价捣固维修作业时机是否最优，将该决策方法应用到杭深线捣固作业实践中。研究结果表明：杭深线轨道质量指数TQI阈值取5.5mm时，为最佳的捣固时间。

英文摘要：

Ballast tamping is an important means for railway maintenance work,but the tamping cost is seldom taken into account when deciding the tamping time.In this paper,a maintenance decision method of the best tamping time was proposed based on the comprehensive evaluation index.The track quality index(TQI)after tamping was used to measure the riding quality and the tamping period was used to measure the tamping cost.By taking both riding quality and tamping cost into consideration,the best time to tamp was recommended.This method was applied to the tamping operation of Hangzhou-Shenzhen high-speed railway.Results from the Hangzhou-Shenzhen high-speed railway show that the best tamping time is when the track quality index reaches5.5mm.