高速铁路无砟轨道路基翻浆模型试验

针对高速铁路无砟轨道出现的路基翻浆病害,构建了足尺的轨道路基翻浆模型试验系统,量测了路基翻浆发生过程中路基的含水率、基质吸力和超孔隙水压力,分析了高速列车动荷载作用下路基动水压力的变化规律,并探讨了高速铁路无砟轨道路基翻浆的机理和影响因素.结果表明:无砟轨道基床表层在雨水入渗条件下基本处于饱和状态,在列车动荷载的长期作用下,易发生翻浆病害;超孔隙水压力的显著增大导致路基发生翻浆,翻浆区域内超孔隙水压力的增量沿基床表层深度方向上保持不变;饱和状态下,底座板两侧路基的超孔隙水压力较路基中心线下更高,更易发生翻浆.降低路基含水率或孔隙水压力可有效地防止和抑制路基翻浆的发生.

Model test of subgrade mud-pumping of ballastless track for high-speed railway

To investigate the subgrade mud-pumping of ballastless track for high-speed railway, a full-scale model test system was built. The moisture content, matric suction, and excess pore water pressure of the subgrade during the process of subgrade mud-pumping were measured, the hydrodynamic pressure characteristics of the subgrade were analyzed under dynamic loads induced by high-speed trains, and the mechanism and influencing factors of subgrade mud-pumping of ballastless track were evaluated. Results show that the subgrade surface layer of ballastless track was basically saturated after rainfall infiltration. The mud-pumping was likely to happen under the dynamic loads of high-speed trains. The subgrade mud-pumping occurred with an increase in excess pore water pressure, and the increment of excess pore water pressure was constant in the mud-pumping region with an increase in the depth of subgrade surface layer. In saturated situation, the excess pore water pressure of the subgrade on both sides of the concrete base was higher than that below the center line of the subgrade, making mud-pumping more likely to occur. Reducing the water content or pore water pressure of subgrade can be an effective way to control and prevent the occurrence of subgrade mud-pumping.