黄土地区重载铁路路堤动力响应及长期沉降

Dynamic Response and Long-term Settlement of Heavy-haul Railway Embankment in Loess Area

研究目的:现场实测是揭示列车运行荷载下铁路路基动力响应规律的重要手段。本文依托黄土地区某铁路专用线工程,通过现场测试获得重载列车运行情况下路堤内部动应力分布规律,研究动应力波形特征及演变趋势,结合室内试验数据预测路堤长期动力沉降。研究结论:(1)列车运行荷载下路基土体的受力形式可以分为双峰型、正弦型和偏正弦型三种;室内动三轴试验加载模式可以分为“短暂间歇+突然过渡”和“连续加载+平缓过渡”两种;(2)多种工况下的峰值/轴重比处于特定的包络范围之内,包络区轮廓可以通过指数函数确定;(3)在本文研究背景下,50年运营期内列车运行引发的路堤动力沉降最大不超过45 mm;(4)本研究结论可以为移动列车荷载下铁路路堤服役状态研究提供借鉴和参考。

Research purposes:Field test is a significance way describing the dynamic response of subgrade under moving train loading.In order to obtain the dynamic stress distribution in the embankment at loess region,the field test was carried out with a heavy haul train passing through,and the characteristics of the dynamic stress curve and its evolution rule were discussed.Additionally,the long-term settlement of embankment was predicted.Research conclusions:(1)The waveform of dynamic stress could be classified into three types,i.e.bimodal type,sine type and deflected sine type.Moreover,the two loading patterns of dynamic triaxial test were also proposed,i.e."short intermission+sudden transition"pattern and"continuous loading+gentle transition"pattern.(2)The ratio of peak dynamic stress versus axial weight under various working conditions is within a specific envelope range.Boundaries of the envelope range could be defined by exponential function.(3)During the 50 years of operation,the dynamic settlement of embankment could not exceed 45 mm in the present study.(4)The research results can provide reference for the service status study of railway embankment under moving train loading.