软土地层45m级超深基坑工程实测变形性状分析  

Analysis on measured deformation performance of 45m class ultra⁃deep foundation pit project in soft soil layer

作　　者：徐中华 王卫东 宗露丹 朱殷航 翁其平 张佶 XU Zhonghua;WANG Weidong;ZONG Ludan;ZHU Yinhang;WENG Qiping;ZHANG Ji(Shanghai Underground Space Engineering Design&Research Institute,East China Architecture Design&Research Institute Co.,Ltd.,Shanghai 200002,China;Shanghai Engineering Research Center of Safety Control for Facilities Adjacent to Deep Excavations,Shanghai 200002,China;School of Ocean and Civil Engineering,Shanghai Jiao Tong University,Shanghai 200240,China)

机构地区：[1]华东建筑设计研究院有限公司上海地下空间与工程设计研究院,上海200002 [2]上海基坑工程环境安全控制工程技术研究中心,上海200002 [3]上海交通大学船舶海洋与建筑工程学院,上海200240

出　　处：《建筑结构》2024年第10期118-127,共10页Building Structure

基　　金：上海市科学技术委员会科研计划项目子课题(13231201006);上海市自然科学基金项目(23ZR1414700)。

摘　　要：以上海软土地区某挖深45m级超深基坑工程为背景,分析了其实测变形特性。结果表明:地下连续墙的侧向位移随开挖深度的增大而逐渐变大,且变形空间效应显著;由于开挖深度大,地下连续墙的绝对侧向变形量也较大,但最大侧向位移平均值与开挖深度的比值仅为0.43%,与上海软土地区挖深小于30m的基坑变形统计平均值接近;地下连续墙及立柱受开挖卸荷影响,竖向位移表现为隆起,且在底板浇筑工况下隆起值趋于稳定,立柱的最大回弹达65mm;各道支撑轴力增量基本发生在紧邻下方土体开挖工况,且最大轴力值基本发生在第六、七、八道支撑中;基坑外地表沉降均呈“凹槽形”,随施工阶段的推移地表沉降逐步增加,且发生最大沉降的位置随之逐步向坑外发展,而无量纲化地表沉降仍处于上海软土地区统计的沉降包络线范围之内;此外,基坑周边管线、磁悬浮的变形均较小,表明基坑工程的安全可控。With the background of a 45m calss ultra-deep foundation pit project in Shanghai soft soil area,its measured deformation performance were analyzed.The results show that lateral displacement of the diaphragm wall increase with the increase of excavation depth,and the spatial effect of deformation is quite significant.The maximum lateral displacement of diaphragm wall is quite large due to the large excavation depth,the ration of the average value of maximum lateral displacements and the excavation depth was only about 043%,which was quite close the statistical average value of deformation of foundation pitfor excavation depth less than 30m in Shanghai district.Diaphragm walls and columns are affected by excavation unloading,the vertical displacement is shown as bulging,and the bulging value tends to stability under the condition of base slab pouring,and the maximum rebound of columns reaches 65mm.The increment of axial force of each course of support basically occur in the excavation condition of the soil body immediately below,and the maximum axial force value basically occurred in the sixth,seventh and eighth course of support.The ground surface settlement outside the foundation pit is"concave shape",and the surface settlement gradually increases with the construction phase,and the location of the maximum settlement gradually develops to the outside of the pit,while the dimensionless ground surface settlement is still within the statistical settlement envelope of the soft soil area in Shanghai.In addition,the deformation of the pipelines around the foundation pit and the maglev are small,indicating that the foundation pit works are safe and controllable.

关 键 词：超深基坑 软土 变形性状 地下连续墙变形 地表沉降 建(构)筑物变形 

分 类 号：TU43[建筑科学—岩土工程]