软土基坑围护的时效性分析及变形预测

Analysis of the time-dependent property of the frame bracingstructure of the foundation pit and prediction of its displacement

运用弹性地基梁法分析基坑围护时,土的水平抗力系数m是一个关键指标。软土基坑围护现场实测表明,土的水平抗力系数具有明显的时效性。文章运用位移反分析方法,可以确定该参数,并给出了上海软土地区m值随时间的变化关系式,由此可预测后续工况和时间内基坑围护结构的变形和稳定性,为实现基坑工程信息化设计与施工创造了条件。

In the analysis of the retaining structure with the elastic beams-foundation method, the resistance coefficient 'm' is a key parameter. The data in situ measured from soft foundation pits shows that the coefficient 'm' depends on time greatly and can be determined by the displacement back-analysis method. A formula which reflects the relation between the parameter 'm' and time in the Shanghai region is presented. A practical example is given to illustrate the successful prediction of the deformation tendency and stability of the frame bracing structure of a foundation pit. The presented work is beneficial to the information-based design and construction of the retaining structure.