围护墙—支护桩复合结构在基坑工程中的应用  

Application of wall-pile-anchor composite supporting structure in foundation pit excavations

作　　者：张怀文[1] 尹一鸣[1] 谢荣昌[1] 

机构地区：[1]中航勘察设计研究院有限公司,北京100098

出　　处：《工程勘察》2014年第2期26-30,共5页Geotechnical Investigation & Surveying

摘　　要：本文依托成都某基坑工程,针对永久性桩锚支护结构,采用杆件有限元法和等值梁法联合设计的方法,研究了大刚度桩锚支护结构的力学性状与变形特征。研究内容涵盖了基坑开挖阶段、正常使用阶段和地震发生阶段三种情况。首先,在基坑开挖阶段建立杆件有限元模型和等值梁法模型,通过优化设计,确定了永久支护结构的技术参数;其次,利用FLAC软件建立三维数值分析模型,验证了基坑开挖工况、地下水恢复工况下数值模型的稳定特征;最后,输入地震荷载,模拟计算模型的动力反应,获得了静动力作用下永久支护结构的力学变形特性曲线。通过设计计算结果与实际监测数据对比,确定了满足整体稳定安全系数≥2.0、锚杆抗拉安全系数≥2.0、荷载分项系数为1.25及工程重要性系数为1.1要求的桩锚支护结构在七度抗震设防烈度下的永久性与安全性。Based on a foundation pit excavation project in Chengdu, the mechanical properties and deformation characteristics of high rigidity permanent pile-anchor retaining structure are studied using beam-structure FEM and equivalent-beam method. The research process covers three conditions which are pit excavation, normal service and earthquake condition. The beam FEM structural model and equivalent- beam model are established in the excavation phrase and the technical parameters of pile-anchor structure are obtained through design optimization. Then A FLAC 3D model is built under the aforesaid conditions and verified again. Finally the mechanical deformation curve under dynamic and static actions is obtained by inputting seismic load to simulate the dynamic response of the model. Comparing the monitoring data and calculation results, it is concluded that the pile-anchor structure could ensure the pit safety satisfying the requirement that the stability coefficient is over 2.0, anchor rod tension resistance coefficient is over 2.0, load coefficient is 1.25 and the importance coefficient of safety engineering is 1.1.

关 键 词：深基坑 永久支护 桩锚结构 数值分析 

分 类 号：TU47[建筑科学—结构工程]