多级/多频列车荷载-湿化耦合作用下有砟轨道路基翻浆冒泥颗粒迁移及动力特性研究

Study on mud pumping particles migration and dynamic characteristics of ballasted track subgrades under multi-stage/multi-frequency train loading-wetting coupling

多级/多频列车荷载-湿化耦合作用下有砟轨道路基翻浆冒泥路基病害严重影响铁路正常运营,其发生机制尚不明确。开展多级/多频列车荷载-湿化耦合作用(MSC-W/MFC-W)下,有砟轨道路基翻浆冒泥模型试验。试验结果表明:在非饱和状态下,2种工况均无显著颗粒迁移现象产生,MSC-W工况下的累积轴向变形较MFC-W工况更加显著;饱和或接近饱和状态下,2种工况均在动孔隙水压力驱动下产生显著翻浆冒泥现象,MFC-W工况的翻浆冒泥程度、细颗粒层位移、道砟污染指数均显著高于MSC-W工况;对于降雨频繁的既有线铁路进行提速改造时要特别重视路基翻浆冒泥病害防控。

The mud pumping disease under multi-stage/multi-frequency train loading-wetting coupling seriously affects the normal operation of railways,and its mechanism is still unclear.The model test study on the mud pumping particle migration and dynamic characteristics in ballasted track subgrade under multi-stage/multi-frequency train loading-wetting(MSC-W/MFC-W)coupling was carried out.The test results show that under the unsaturated state,there is no significant particle migration phenomenon in the two working conditions,the accumulated axial deformation under the MSC-W working condition is more significant than that under the MFC-W working condition;Under the saturated or near saturated condition,the two working conditions result in significant mud pumping phenomenon by the driving force of dynamic pore water pressure.The mud pumping degree,fine particle layer displacement and ballast fouling index under MFC-W working condition are significantly higher than those under MSC-W working condition;Thus,special attention should be given to the prevention and control of subgrade mud pumping during the speed-raising reconstruction of the existing railway with frequent rainfall.