摘要
对佛山地区某42 m厚淤泥土地层中地铁车站深基坑工程施工全过程的实测数据结合工序进行统计分析,选取基坑标准段围护结构墙体水平位移、地表沉降、墙顶位移、支撑轴力及地下水位等,重点分析基坑开挖变形的特点与规律,结合现场经验提出软土基坑变形控制措施,为相似工程提供借鉴。研究表明:(1)开挖导致基坑围护结构墙体向坑内侧凸进变形,最大墙体水平位移为120.8 mm(7.1‰H,H为基坑深度),最大变形深入开挖面以下约3 m;(2)围护结构墙体变形随开挖深度增大而加快,第一、二、三层土开挖引发变形占比约为2∶3∶5;(3)墙体变形增长主要发生在土方开挖期间,引发的变形量约占总量的70%;(4)周边地表沉降量为围护墙体位移的1.25~1.46倍,沉降影响范围超出了监测点布置范围;(5)支撑轴力在土方开挖期间快速增长,支撑轴力在整个基坑施工过程中均维持在较低水平;(6)结合佛山地区深厚淤泥地层深基坑施工的现场经验,总结提出了基坑变形控制对策。
The measured data of the whole process of the subway station deep foundation pit excavation which is located in silt stratum with a thickness of 42 m in Foshan are analyzed combined with the construction procedure.The horizontal displacement of the retaining wall,ground surface settlement,displacement at the top of wall,axial force of strut,and underground water level of the standard section in the excavation are measured and selected,and a thorough analysis of the characteristics and laws of the excavation deformation is taken.Combining the field experience a few countermeasures for deformation control of the excavation in soft soil are put forward to provide reference for similar projects.The results show:(1)The excavation causes the retaining wall to protrude to the inside of pit,the maximum horizontal displacement of the wall is 120.8 mm(7.1‰H,H is the depth of pit).Meanwhile,the maximum displacement is about 3m below the excavation surface.(2)With the increase of excavation depth,the deformation of retaining wall is accelerated,the proportion of deformation caused by excavation of the first,second and third layers is about 2∶3∶5.(3)The retaining wall deformation increases sharply during excavation accounting for about 70%.(4)The surrounding surface settlement is 1.25~1.46 times of the displacement of the retaining wall,and the influence range of settlement exceeds the layout range of monitoring points.(5)The axial force of strut increases rapidly during excavation with closely relationship to the retaining wall deformation,and the axial force maintains at a low level during construction.(6)According to construction experience of deep soft soil foundation pit in Foshan,this paper puts forward some foundation pit deformation control measures.
作者
夏文宇
Xia Wenyu(Foshan Railway Investment Construction Group Co.,Ltd.,Foshan,Guangdong 528000,P.R.China)
出处
《地下空间与工程学报》
CSCD
北大核心
2022年第S02期1056-1062,共7页
Chinese Journal of Underground Space and Engineering
关键词
地铁车站
基坑变形性状
统计分析
深厚软土
基坑支护
subway station
deformation behavior of foundation pit
statistical analysis
deep soft soil
foundation pit support
