摘要
为揭示软土深基坑开挖过程中支护体系和周边岩土体的受力和变形特性,以南京河西地区地质条件较差的某地铁深基坑工程为例,做出针对性的监测方案,并对监测成果进行综合分析。监测表明,随着基坑的开挖,不仅立柱会出现明显的上抬,作为支挡结构的地下连续墙也会发生一定量的上抬。当支撑两端地下连续墙的上抬量差异较大时,将会使支撑产生较大的次生应力,严重影响支撑的受力状态。在基坑降水和开挖过程中,坑外土体会出现特殊形态的沉降槽,并对土体深层水平位移产生影响。地下连续墙深层水平位移最大值一般出现在坑底开挖面下附近,适当增加预加轴力能够有效控制地下连续墙的深层水平位移。监测成果为研究软土地基基础深基坑施工过程中工程结构的安全性提供了可靠的支持,可为类似工程提供参考和依据。
In order to reveal the stress and deformation characteristics of the supporting system and surrounding rock and soil during the excavation process of soft soil deep foundation pit,a deep monitoring project of a subway with poor geological conditions in Hexi area of Nanjing is taken as an example to make a targeted monitoring plan.And conducted a comprehensive analysis of the monitoring results.The monitoring results indicate that the diaphragm wall will also lift,not only the column,with excavation of the foundation pit.When the difference in the amount of lifting on the diaphragm wall at both ends of the support is large,the support will generate a large secondary stress,which seriously affects the stress state of the support.During the foundation pit dewatering and excavation process,a special form of settlement tank will appear in the soil outside the pit,and it will affect the horizontal displacement of the soil.Deep horizontal displacement of diaphragm wall maximum appeared in the excavation near the surface,increasing pre axial force can effectively control the horizontal displacement of deep underground continuous wall.The research results can provide reliable guidance for the engineering safety in the construction process of the foundation pit and some reference for similar engineerings.
作者
刘宁
凌青
叶旦
王亮
LIU Ning;LING Qing;YE Dan;WANG Liang(China Design Group Co. , Ltd, Nanjing 210014,China)
出处
《现代交通技术》
2018年第6期78-83,共6页
Modern Transportation Technology
关键词
软土地基
深基坑
基坑监测
变形特性
soft foundation
deep foundation pit
monitoring
deformation properties
