软土地基桩板结构路基离心模型试验研究

为研究和分析软土地区桩板结构路基的沉降特性，采用离心模型试验方法对不同预压时间（6/12个月）下的桩板结构路基进行了模拟试验。试验结果表明，桩板结构路基沉降主要发生在施工期，预压时间超过16个月后，沉降比例超过80%；预压土卸载期间路基回弹与否与土层性质和预压时间有关；超载预压可以显著降低工后沉降，预压12个月后路基工后沉降相比预压6个月沉降减小了71%；在桩板结构路基施工过程中，桩基存在负摩阻力，中性点位置的变化是一个动态的过程，其与桩长的比例在0.47~0.70之间。

Centrifugal model test of pile-plank subgrade in soft ground

To analyse the settlement characteristics of pile-plank structure in soft soil subgrade, the centrifugal model test is used to imitate the pile-plank subgrade with different preloading times about six moth and twen-four month. It is shows that the settlements of pile-plank subgrade mainly happen during construction in which the proportion of settlement will exceed 80% when the preloading time is more than 6 months. Whether the settlement of pile-plank subgrade will rebound or not during unloading time is related to the soil properties and preloading time. Overload preloading can significantly reduce post-construction settlement which can be reduced 70% for twen-four month to 6 nonth of preloading time. During construction of pile-plank structure subgrade, pile foundation exists negative friction and neutral position change is a dynamic process, ratio pile length between 0.47~0.7.