北京地铁薄壁地下连续墙基坑变形规律统计分析  

Statistical Analysis of Beijing Subway Thin-walled Diaphragm Wall Foundation Pit Deformation Law

作　　者：祝建勋[1,2] 杨春阳 李永伟 赵智涛 钟巧荣[1,2] 宋云兴[4] ZHU Jianxun;YANG Chunyang;LI Yongwei;ZHAO Zhitao;ZHONG Qiaorong;SONG Yunxing(Beijing Agile-Tech Engineering Consultants Co.,Ltd.,100050,Beijing,China;National Engineering Lab for Green and Safe Construction Technology in Urban Rail Transit,100037,Beijing,China;Beijing Rail Transit Construction Management Co.,Ltd.,100068,Beijing,China;Beijing Gonglian Jieda Highway Maintenance Engineering Co.,Ltd.,100071,Beijing,China)

机构地区：[1]北京安捷工程咨询有限公司,北京100050 [2]城市轨道交通绿色与安全建造技术国家工程实验室,北京100037 [3]北京市轨道交通建设管理有限公司,北京100068 [4]北京公联洁达公路养护工程有限公司,北京100071

出　　处：《城市轨道交通研究》2024年第7期127-132,140,共7页Urban Mass Transit

基　　金：北京市轨道交通建设管理有限公司双创基金项目(SCJJ2023001)。

摘　　要：[目的]地下连续墙(以下简称“地连墙”)厚度对基坑变形量与变形模式的影响较为明显,尤其是薄壁地连墙对于基坑开挖和坑边荷载十分敏感。因此,有必要对北京地铁不同壁厚的地连墙基坑变形规律进行研究。[方法]以北京地铁6座薄壁地连墙车站基坑工程为例,使用统计学方法对其地面竖向变形、地连墙墙顶竖向变形、地连墙水平位移及钢支撑轴力的监测数据进行统计分析。[结果及结论]薄壁地连墙基坑的地面变形可分为隆起-沉降型和沉降型两种,且地面变形中隆起变形的占比较高。土方开挖阶段,地连墙呈快速隆起趋势,开挖结束后墙顶隆起值产生小幅回落,并最终达到稳定值。根据地连墙变形特征,将其分为正常抛物线型、荷载抛物线A型、荷载抛物线B型3种类型。地连墙最大变形位置一般处于0.50H~0.85H(H为基坑深度),累计变形量集中于10~20 mm。第1道钢支撑轴力变化特征较为明显,其曲线可分为快速上升、快速下降、缓慢下降、快速上升4个阶段。[Objective]The thickness of diaphragm walls significantly affects the amount and mode of foundation pit deformation,thin-walled diaphragm walls are especially sensitive to excavation and edge loads of foundation pit.Therefore,it is necessary to study the deformation law of foundation pit diaphragm walls with different thicknesses in Beijing Subway.[Method]Taking six thin-walled diaphragm wall station foundation pit projects in Beijing Subway as examples,statistical analysis is conducted on monitoring data of ground vertical deformation,diaphragm wall top vertical deformation,horizontal displacement of diaphragm walls,and axial force of steel supports using statistical methods.[Result&Conclusion]The thin-walled diaphragm wall foundation pit ground deformation can be classified into heave-subsidence type and subsidence type,with a higher proportion of heave ground deformation.During soil mass excavation phase,the diaphragm wall exhibits a rapid upheaving trend,followed by a slight rebound of wall top uplift value after excavation completion,and eventually reaching a stable value.Based on the deformation characteristics of diaphragm walls,three types are identified:normal parabola,load parabola A and load parabola B.The maximum deformation of diaphragm walls generally occurs between 0.50 H and 0.85 H(H as the excavation depth),with cumulative deformation concentrated in the range of 10 and 20 mm.The axial force variation of the first steel support is rather distinct,and its curve could be divided into four stages:rapid rise,rapid decline,slow decline,rapid rise.

关 键 词：地铁 薄壁地连墙 基坑变形 

分 类 号：U231.3[交通运输工程—道路与铁道工程] TU753[建筑科学—建筑技术科学]