摘要
南宁市思贤路38号危旧房改造项目基坑采用地下连续墙与双环形内支撑的支护形式,周边环境复杂,考虑基坑施工过程中的时空效应作用,对基坑不同位置在各施工阶段的监测数据进行了分析研究,得到以下结论:深基坑变形与周边环境相关,周边建筑物的存在会增大基坑变形;受时空效应影响,围护结构水平位移随基坑开挖不断增大,沿远离坑角的方向呈增大趋势,在基坑长边中部达到最大;位移曲线呈两种形式:一种为抛物形,一种由于周边不平衡堆载近似呈悬臂式;基坑的边界抑制效应沿远离坑角方向逐渐衰减,基坑长深比对空间效应有较大影响;合理考虑时空效应影响,降低墙体无内支撑时的暴露面积和时间,能有效减少围护结构变形;路面地表沉降与围护结构顶部位移有关,周边建筑物沉降沿远离基坑侧壁方向逐渐减小;周边环境对内支撑轴力有较大影响,受边界抑制效应,位于长边中部的对撑轴力远大于坑角处的角撑轴力,空间效应明显。
The housing reconstruction project at No.38 Sixian Road,Nanning adopts the support scheme of diaphragm wall and double annular arched girders.The surrounding environment of the excavation pit is complex.Considering the space-time effect of the excavation process,the monitoring data of different positions of the pit in each construction stage are analyzed,and the following conclusions are drawn that the deformation of deep excavation pit is related to the surrounding environment,and the existence of surrounding buildings will increase the deformation of the pit;affected by the temporal and spatial effects,the horizontal displacement of the retaining structure increases with the excavation of the foundation pit,and tends to increase along the direction away from the pit corner,and reaches the maximum in the middle of the long side of the excavation pit;the displacement curves show in two forms,the first one is parabolic,the other one is cantilever due to the unbalanced surrounding load;the boundary inhibition effect of the pit decreases gradually along the direction away from the pit corner,and the ratio of pit length to depth has a great influence on the spatial effect;considering the effect of time and space,reducing the exposed area and time of wall without internal support can effectively reduce the deformation of retaining structure;the pavement settlement is related to the top displacement of the retaining structure,and the settlement of the surrounding buildings gradually decreases along the direction away from the pit side;the surrounding environment has a great influence on the internal supporting axial force,due to the boundary inhibition effect,the lateral support axial force located in the middle of the long side is much larger than the force in diagonal braces at the pit corner,and the spatial effect is obvious.
作者
范立军
Fan Lijun(China Railway Construction Group Southern Engineering Co.,Ltd,Nanning 530000,China)
出处
《工程勘察》
2023年第11期9-17,共9页
Geotechnical Investigation & Surveying
基金
国家自然科学基金资助项目(52068004)
广西重点研发计划项目(AB19245018).
关键词
深基坑
复杂环境
监测分析
双环形内支撑
时空效应
deep excavation pit
complex environment
monitoring and analysis
double annular arched girder support
effect of time and space
