相邻基坑同步施工对围护结构受力变形的影响实例研究  

A case study on the influence of synchronous construction of adjacent foundation pits on the stress and deformation of bracing structures

作　　者：彭麟 李悦 张舶航 PENG Lin;LI Yue;ZHANG Bo-hang(Nanjing Branch of Jiangsu UnionTechnical Institute,Nanjing210019,Jiangsu,China;Jiangsu Engineering Survey and Research Institute Co.,Ltd.,Yangzhou225000,Jiangsu,China)

机构地区：[1]江苏联合职业技术学院南京分院,江苏南京210019 [2]江苏省工程勘测研究院有限责任公司,江苏扬州225000

出　　处：《地基处理》2024年第2期146-153,共8页Journal of Ground Improvement

摘　　要：相邻深基坑同步开挖施工对围护结构体系受力和变形的影响尚不明确。通过对同步施工的某建筑物深大基坑与相邻地铁车站基坑进行监测,对比分析了相邻部位和非相邻部位围护结构顶部位移、水平支撑轴力、深层土体水平位移、地表沉降以及地下水位等的变化。监测结果表明:(1)当车站基坑开挖深度较浅时,建筑基坑相邻部位桩因两侧土压不平衡导致桩顶向坑外侧移而竖向位移出现“上浮”现象,但是,当车站基坑开挖深度超过建筑基坑深度时,建筑基坑相邻部位桩桩顶水平位移转向坑内加剧发展而竖向位移出现“回落”现象;(2)受邻近基坑卸载影响,建筑基坑水平支撑轴力将减小;(3)两基坑间地表沉降大于非相邻部位,且地表沉降变化与桩顶位移和地下水位变化相关联;(4)相邻部位基坑壁深层土体水平位移有向坑外变形的趋势。The influence of synchronous excavation of adjacent deep foundation pits on the stress and deformation of the bracing structure system remains unclear.By monitoring the deep and large foundation pit of a building and the foundation pit of a subway station constructed simultaneously,a comparative analysis was conducted on the changes in the displacement of the top of the wall,axial forces of horizontal struts,horizontal displacement of deep soil layers,surface settlement,and groundwater level for both the adjacent and the non-adjacent retaining structures.The monitoring results revealed the following findings:(1)In cases where the excavation depth of the tunnel station foundation pit is shallow,the adjacent retaining piles of the building foundation pit move toward the outside of the pit due to unbalanced soil pressure,and are raised.Conversely,when the excavation depth of the tunnel station pit surpasses that of the building foundation pit,the horizontal displacement of the pile top in the adjacent sections of the building foundation pit shifts towards the pit,causing a“falling back”phenomenon of vertical displacement.(2)The axial forces of horizontal struts of the building foundation pit will decrease due to the influence of adjacent foundation pit unloading.(3)The surface settlement between the two foundation pits exceeds that of non-adjacent sections,and its changes are related to the displacement of the pile top and the changes in groundwater level.(4)The horizontal displacement of the soil at the adjacent sections of the foundation pit wall exhibits deformation towards the outer side of the pit.

关 键 词：相邻基坑 同步施工 围护结构 受力和变形 桩顶位移 水平支撑轴力 地表沉降 

分 类 号：TU473.2[建筑科学—结构工程]