软土路基“波浪型”不均匀沉降及其机制分析

在软土地基上修建道路,变形是控制道路质量和正常使用的主要因素。天津东疆港道路建立在经真空预压加固后的吹填土地基上,道路使用3 a后产生了严重的"波浪型"不均匀沉降,严重影响了车辆的行驶及人的生命安全。通过分析软土路基产生波浪变形的机制,提出了道路在建成后产生初始波浪变形,在车辆荷载作用下加剧了这种不均匀沉降的理念;建立了软土路基在波浪变形初值缺陷条件下的力学模型,通过力学分析与计算得出,在初始波浪变形条件下路基波谷受到比波峰大的车辆荷载;路基波峰与波谷处车辆动载大小的不同是加剧地基不均匀沉降变形的原因。提出利用土工格栅的加筋作用可减小不均匀沉降,通过有限元方法分析了该措施的加固效果。

Study of wave type asymmetry settlement and its mechanism of soft soil roadbed

The deformation is the dominant factor of the quality of the road constructed on the soft soil foundation. Tianjin Dongjiang port is located on the hydraulic filled soil foundation which is improved by using vacuum preloading method. Roads in this area often suffer wave type asymmetry settlement, which seriously affects the usage of the road and causes damage to both vehicles and human being. It is found that the initial wave asymmetry deformation of the road on very soft soil foundation is usually existing and will be developing continuously under the traffic load. The mechanism of the wavy failure of the road is discussed by establishing a mechanical model. The method of using geogrids to reduce the asymmetry deformation is proposed; the reinforcing effect is analyzed using finite element method.