高速公路拓宽路基病害机理及防治

Damage mechanism and prevention of widened embankment

为了分析高速公路拓宽路基病害机理,以京石高速公路拓宽为工程背景,在FLAC环境下利用Fish函数方法建立了高速公路路基拓宽的数值分析模型,研究了地基沉降对拓宽路基内竖向应力、水平应力和剪切应力的影响,结果表明:在路基拓宽中路基顶部拼接处首先出现拉应力,随着地基沉降的发展,路基顶部拼接处的拉应力区不断发展,并引起路基和路面出现纵向开裂;由于拓宽路基填筑高度不同,路基竖向附加应力分布不均,从而使得路基横向出现不均匀沉降;剪应力主要集中在拓宽路基中部,对拓宽路基病害贡献不大.最后提出了拓宽路基病害防治措施.

To analyze the damage mechanism of widened embankments,based on a case of widened Jingshi highway,Fish function in FLAC was used to establish the numerical model of the widened highway embankment in this study.Also,the effects of foundation settlement on the vertical stress,horizontal stress and shear stress in the widened roadbed were investigated.The results show that: tensile stress initially occurs at the top of the widened roadbed.With the development of foundation settlement,the tensile stress zone is also extended and results in the longitudinal cracks in the embankment and pavement;due to different filling height,the uneven vertical additional stress distribution occurs,which causes the transverse differential settlement for the subgrade;concentrated shear stress appears in the middle of the widened embankment,which has little effect on the widened roadbed.The prevention measures for the widened embankment damage are presented.