基坑施工对周边既有砌体结构房屋影响的实测分析研究  

Research on Response of Existing Masonry Structures to an Adjacent Excavation

作　　者：方林[1] 张波[1] 韦欣欣[1] 金国芳[1] 

机构地区：[1]同济大学结构工程与防灾研究所,上海200092

出　　处：《结构工程师》2014年第4期162-169,共8页Structural Engineers

摘　　要：根据某基坑周边2幢既有建筑的现场实测数据，分析了软土地区考虑时间效应后基坑施工对周边既有砌体结构房屋的影响。基坑开挖完成后，由软土的流变性引起的周边既有建筑沉降具有明显的时间效应。基坑外水位在基坑降水、开挖的过程中相对比较平稳，但降水对周边既有建筑沉降影响较大。距基坑围护墙（1．0～2．0）H 范围内沉降测点由时间效应引起的沉降达到开挖完成时沉降量的1倍左右。三维沉降分布表明既有建筑的沉降形态主要受基坑的三维变形效应和时间效应影响。施工完成后，2幢既有建筑在东西方向上均整体表现为上拱变形，越靠近基坑中部上拱相对变形越大。对2幢既有建筑开裂受损及倾斜情况进行了检测调查，2幢既有建筑最大角变位分别为1/2221、1/1363，表明本基坑施工方案及相关保护措施有效地控制了周边既有建筑的沉降变形，确保了周边既有建筑的结构安全和正常使用。Taking the time effect into account,response of existing masonry structures to an adjacent excava-tion in soft clay was analyzed based on the observation data of two buildings in this study.After the excavation of Region 1 ,building settlements induced by the rheology of soft clay had obvious time effect.Although the water level outside the excavation was relatively stable during the process of precipitation and excavation,pre-cipitation had great influence on settlements of adjacent existing buildings.Settlements of the optical survey points caused by time effect in the distance of （1 .0 -2.0）H apart from the retaining walls can be equal to those at the end of the excavation of Region 1 .It can be concluded from the three-dimensional settlement dis-tributions that the pattern of building settlement was primarily affected by the three-dimensional deformation behavior and time effect of excavation.The global deformation modes of the two buildings experienced hog-ging,relative deflection of which was larger if the location was much closer to the middle of excavation in the east-west direction after construction.Cracking and damage of adjacent buildings was detected and investigated at the site.The maximum angular distortions of the adjacent buildings were 1 /2221 and 1 /1 363 respectively, indicating that settlements of adjacent buildings were effectively controlled by the excavation program and the corresponding protective measurements,and hence the structural safety and normal use of adjacent existing buildings was ensured.

关 键 词：基坑施工 既有砌体结构 时间效应 沉降 角变位 

分 类 号：TU753[建筑科学—建筑技术科学] TU196