高铁单线路基循环累积变形分析方法及其可靠度分析

Analysis approach and reliability analysis of cumulative cyclic deformation of subgrade of single high-speed railway line

极限状态设计方法是我国铁路工程走向国际的重要步骤,而路基循环累积变形是设计中控制标准之一。基于永久应变经验公式,提出列车荷载作用下路基循环累积变形的预测模型,通过1∶1路基模型试验验证了该预测模型的适用性。在此基础上,引入动应力及路基填料参数的变异性,建立路基循环累积变形的极限状态方程,并根据武广线现场实测数据确定路基面动应力幅值的变异系数。通过可靠度指标对计算参数变异系数的敏感性进行分析,分析动应力及填料参数的变异性等控制因素的影响作用,并确定了变异程度控制范围作为实际工程中的控制标准。可靠度分析的方法考虑了荷载及填料参数的不确定性因素,使得理论预测更加接近工程实际。

Limit state design is an important step for internationalization of Chinese railway. Cumulative cyclic deformation of subgrade is one of the control standards in railway design. Based on the empirical formula of permanent strain,a prediction model was proposed to predict the cumulative cyclic deformation of high-speed railway subgrade. 1∶1 physical model tests were carried out to calibrate its applicability. A limit state equation of cyclic cumulative deformation of subgrade was developed considering the variation of dynamic stress and material parameters. Coefficient of variation（COV） of dynamic stress on subgrade surface was determined with the measured data from the high-speed railway of Wuhan—Guangzhou. The effects of the dominant parameters on the reliability index were analyzed to investigate the effect of the variation of dynamic stress and material parameters.