土岩二元地层条件下深基坑“吊脚桩”变形特性研究

Investigation to the Deformation Characteristics of "Hanging Foot Pile" in Deep Foundation with Soft Soil and Hard Rock

本文以厦门轨道交通火炬园站为工程背景,研究了厦门地区上软下硬的土岩二元复杂地质条件下深基坑“吊脚桩”的变形特性问题.基于PLAXIS有限元分析软件,分析了该支护体系的受力变形机理,掌握其工作力学特性规律.研究了“吊脚桩”嵌固深度、留台宽度以及锁脚锚索的自由段长度对基坑受力、变形的影响并得出结论:通过与基坑的全过程开挖监测数据对比,表明数值分析能很好地模拟土岩二元复杂地质条件下深基坑“吊脚桩”围护结构在开挖过程中受力及变形的变化过程,并对嵌固深度、留台宽度以及锁脚锚索的自由段长度提出了相应要求.

In this paper,the deformation characteristics problems of deep foundation pit under the dual and complex geological conditions of soft soil and hard rock which supported by“hanging foot pile”was studied based on engineering background of Huojuyuan Metro Station in Xiamen area.In light of the PLAXIS finite element analysis software,the mechanism of the force and deformation of the support system was analyzed and its working mechanical characteristics were mastered.'The efects of embedding depth,the width of the stay and the free length of the anchor on mechanics and deformation properties of the deep foundation pit were studied.Through comparing the monitoring data of excavation in the whole process of foundation pit,the results showed that the numerical analysis could simulate the changing of stress and deformation process in the“hanging foot pile”excavation process well,and also brought forward relevant requirements for the embedding depth,the widh of the stay and the free length of the anchor.