长江中下游一级阶地地层结构特征及深基坑变形破坏模式分析

Studies on strata characteristics and model of deformation and collapse of deep excavation in the first terrace of Yangtze River

总结分析了长江中下游一级阶地地层结构特征,即由上部软弱粘性土与下伏砂性土层构成的二元沉积韵律,及其对深基坑工程的影响;探讨了软土深基坑的主要变形破坏模式。针对由于开挖软土层而引起的基坑变形、坑底隆起和整体失稳,以及由于揭露或揭穿含水层所产生的地下水水患和抽降承压水造成的地面沉降等深基坑工程环境影响,提出了相应的防治措施和建议。

The strata configuration characteristics of typical binary-layer structural sedimentation rhythm in the first terrace of middle and lower reaches of Yangtze River, which have upper soft soils and lower sandy strata, were summarized and analyzed. The influence and the model of deformation and collapse of deep excavation were studied. The corresponding countermeasures were proposed for the environmental influences of deep excavation engineering caused bY lateral displacement, base heave and subsidence, even collapse while excavating in soft soils and by piping and seepage failure and ground settlement while exposing or revealing ground water and dewatering confined water.