高速铁路不同路基结构防冻胀试验研究

Anti-frost Heave Study of High Speed Railway Subgrade with Different Structure

为减小季节性冻土区路基冻胀对高速铁路无砟轨道平顺度的影响,采用对不同封闭型式的路基结构进行降雨条件下路基渗流模拟,分析路基土体内压力水头与含水量变化情况。数值模拟结果显示,路基表层无封闭型式能够在降雨时及时排出路基表面水量,基床底层顶面的排水板有效阻隔了地表水进入基床底层,降低了降雨入渗对底座板下部基床含水量的影响。在两种不同封闭型式的路基试验段,选择代表性断面埋设位移传感器与温度传感器,监测路基冻胀变形与冻结深度。现场监测结果表明,当路基主要为浅层冻胀,地下水对路基本体含水量影响较小的情况下,路基表层无封闭型式的冻胀量较小。

In order to reduce the influence of subgrade frost heaving on high-speed railway unballasted track smoothness in seasonal frozen soil region, using different closed structure subgrade to conduct percolation model simulation under the condition of rainfall , and analysed the pressure head and water content changes of subgrade. The model simulation test results indicated that, non-closed structure discharged the groundwater of rainfall in time, the drainage plate at the top of the bottom bed layer resisted the infiltration into subgrade effectively, this structure reduced the influence of water content in bottom bed with rainfall infiltration. The deformation sensors and temperature sensors were embedded in representative test section of different closed structure to monitor the frost heaving deformation and freezing depth. The experiment results show that when the frost heave occurred at shallow depth and the under groundwater had less influence on subgrade water content, the subgrade frost heave deformation was smaller with non-closed structure.