土岩组合地层地铁深基坑开挖性状分析及预测

Analysis and Prediction of Excavation Behavior of Metro Deep Foundation Pit in Soils Underlain by Rock

通过对金华地区土岩组合地层地铁深基坑监测数据分析,总结了土岩组合地质条件下基坑水平位移曲线与周边沉降曲线的关系和特点,得到了基坑最大水平位移量、最大地表沉降量、基坑影响范围与基坑开挖等关系。研究结果表明,基坑最大水平位移量平均值为0.023%H(H为基坑开挖深度,下同);地表最大沉降量均值为0.035%H;最大水平位移深度出现在约为0.59H处;基坑影响范围约为1.5H;围护结构的最大水平位移与地表最大沉降大体呈线性关系,上限和下限差异值较小。该文结合基坑水平位移曲线特点,提出两种预测桩体水平位移的方法,为金华地区以及其它相似工程的设计和施工提供参考。

Based on concluding data statistics of metro deep foundation pits in soils underlain by the rock in Jinhua area,the characteristics between horizontal displacement curves and subsidence curves in geology condition of soils underlain by rock were summarized,and the relations between excavation depth and maximum horizontal displacement,maximum surface settlement as well as the influence range of the foundation pit were obtained.The results have shown that the mean value of maximum horizontal displacement is about 0.023%H while the main value of surface settlement is nearly 0.035%H.It also shows the maximum horizontal displacement depth is about 0.59 H,and the influence range of foundation pit is about 1.5 H.Frommathematical aspect,the maximum horizontal displacement of retaining structure has a linear relationship with maximum surface subsidence,meanwhile,the difference between the upper limit and the lower limit is small.Furthermore,according to the characteristics of horizontal displacement curves,two methods for predicting horizontal displacement of piles were put forward in this paper,and the predicted displacement of piles by two methods are good agreement with the measured values which provides a reference for the design and construction of similar projects.