厚淤泥土层中深基坑开挖响应的实测研究  

Experimental Research on Excavation Response of Deep Foundation Pit in Thick Silt Soil Layer

作　　者：梁凌 LIANG Ling(China Railway 16th Bureau Group Beijing Metro Engineering Construction Co.Ltd.,Beijing 100018,China)

机构地区：[1]中铁十六局集团北京轨道交通工程建设有限公司,北京100018

出　　处：《铁道建筑技术》2023年第7期177-181,199,共6页Railway Construction Technology

基　　金：中铁十六局集团有限公司科技研发计划项目(K2019-20B)。

摘　　要：伴随城市快速发展、人口密度持续增加、建设用地愈发紧张等问题,诸多城市着力寻求地下空间以从根源上解决问题。在此过程中,大量的深基坑开挖工程往往会对地层及周围环境产生一定的扰动,这种扰动在一些厚软弱土层中显得尤为敏感。以苏州地铁昆山时代大厦站基坑为例,选取标准段对地下水位、地表沉降、内支撑轴力、墙顶竖向/水平位移以及墙身水平位移进行实时监测数据的系统分析。研究发现:(1)基坑开挖改变地层应力状态,诱发地层产生持续沉降变形,基坑两侧的地表沉降横断面曲线大致呈有限范围的“V”字形;(2)基坑开挖过程中上部支撑轴力会伴随下部支撑的施加而减小,而下部支撑轴力则会快速增加并在地板浇筑完成后都趋于稳定;(3)基坑开挖过程中地层应力状态的改变会诱发围护墙的抬升,也会引起墙顶向坑外变形;(4)地下连续墙墙身在基坑开挖过程中呈中部向坑内侧凸出的“鼓肚形”变形,最大水平位移逐渐增大,其位置逐渐下移至坑底附近。With the rapid development of cities,the continuous increase of population density,and the increasing shortage of construction land,many cities are focusing on seeking underground space to solve the problem.In this process,a large number of deep foundation pit excavation projects often produce certain disturbances to the stratum and surrounding environment,which are particularly sensitive in some thick and weak soil layers.Taking the foundation pit of Suzhou Rail Transit Kunshan Times Building Station as an example,the standard section is selected to systematically analyze the real-time monitoring results of groundwater level,surface subsidence,axial force of internal support,top displacement of retaining wall(vertical/horizontal)and horizontal displacement of retaining wall body.The research found that:(1)the excavation of the foundation pit changes the stress state of the stratum and induces continuous settlement and deformation of the stratum,the surface settlement cross-sectional curves on both sides of the foundation pit are roughly in the shape of a limited“V”.(2)During the excavation of the foundation pit,the axial force of the upper support will decrease with the application of the lower support,while the axial force of the lower support will increase rapidly and become stable after the floor is poured.(3)The change of the stratum stress state during the excavation process will induce the uplift of the retaining wall,and also cause the top of the wall to deform out of the pit.(4)During the excavation process of the foundation pit,the wall body of the retaining wall is deformed in the shape of a“bow”,the maximum horizontal displacement gradually increases,and its position gradually moves down to the vicinity of the pit bottom.

关 键 词：深基坑 淤泥 沉降 监测 

分 类 号：U231.3[交通运输工程—道路与铁道工程]