泡沫轻质土在高速公路改扩建工程路堤抬升段中应用的数值模拟

Numerical simulation on the application of foam lightweight soil in the embankment upgrading section of highway expansion projects

在我国高速公路改扩建工程中,由于新旧标准的差异,导致出现了纵断面抬升的路段,该路段不仅需要考虑拼宽路基的沉降问题,还需要考虑抬升的附加荷载作用在老路基所产生的附加沉降影响。本研究以江苏某高速公路改扩建工程为实例,阐述了泡沫轻质土置换老路的厚度计算方法,运用有限差分软件建立填土和泡沫轻质土拼宽改造的数值模型,对比分析了泡沫轻质土改造后地基土的沉降和变形的特征,发现泡沫轻质土引起的地基土的塑性增量较小,塑性变形增量区域较小,并探讨了泡沫轻质土路堤施工质量的控制要点和注意点,为软土地基中的高速公路的改扩建工程提供一套控制差异沉降的设计和施工方法。

In the construction and expansion projects of expressways in our country,differences in new and old standards have led to the occurrence of road sections with raised longitudinal profiles.These road sections not only need to consider the settlement of the fill width embankment but also the additional load caused by the raised section affecting the additional settlement of the old subgrade.This study takes a high-speed expressway construction and expansion project in Jiangsu Province as an example to expound the calculation method of the thickness of foam lightweight soil replacing the old subgrade.A numerical model of fill soil and foam lightweight soil reconstruction using finite difference software was established,and the characteristics of settlement and deformation of the foundation soil after foam lightweight soil reconstruction were compared and analyzed.It was found that the plastic increment of the subgrade soil caused by foamed lightweight soil is relatively small,and the area of plastic deformation increment was also relatively small.The control key points and considerations for the construction quality of foam lightweight soil embankments were discussed,providing a set of design and construction methods to control differential settlement for expressways built on soft soil foundations.