膨胀土路堑基床新型防水层振动荷载下服役性能试验研究

膨胀土路堑基床病害是铁路工程中亟需解决的关键技术问题。针对新建云桂线膨胀土地段高速铁路工程实际,开展膨胀土路堑基床模型室内激振试验,研究新型防水结构层在干燥、降雨、地下水位上升三种极端服役条件下的动力性能及防水效果,并结合现场实测数据进行了分析。分析结果表明：服役环境对新型基床结构的动力特性影响显著,降雨和地下水位上升均引起基床动应力、速度及加速度不同程度的增加;新型防水结构层可加快基床内部动应力的衰减,动应力沿横向距离近似呈“Z”形分布,在轨道正下方出现峰值,距线路中线5.0m以外受振动影响较小;新型防水结构层能满足的防水、隔水、抗振、减振的要求,对提高铁路线路的平顺性和稳定性具有积极意义。研究成果可为新建云桂膨胀土高速铁路工程建设及同类工程实践提供参考。

Test study on working property of water-proof layer of cutting subgrade under vibrating load in expansive soil areas

The defect of cutting subgrade in expansive soil is a key technical problem of railway engineering that need to solve urgently. According to the actual conditions of the new Yun-Gui lines of high-speed railway project in expansion area, the model test of cutting subgrade of expansive soil is carrying out to study the dynamic performance and waterproof effect of new water-proof constructer layer under three kinds of extreme service condition (dry, raining, and underground water rising), and combining with the field measured data is analyzed. The analysis results show that the influence of service environment on dynamic characteristics of new subgrade structure is significant. The dynamic stress, velocity and acceleration of subgrade are increase to different extents when raining and underground water rising. The waterproof layer can accelerate the attenuation of dynamic stress in subgrade, the dynamic stress along the transverse distance is "Z" shape distribution, and the peak value appear at below the track, and it is less affected by vibration approximately 5.0 metres from the center line. The New type waterproof structure layer can meet requirements of waterproof, impermeable, anti-vibration and impact-absorbing, and it has positive significance to improve the ride performance and stability of railway track. The conclusion can be referenced for newly built Yun-Gui high-speed railway of expansive soil and similar projects.