深基坑开挖与周边既有建筑物改造相互影响研究

基于上海体育馆、上海游泳馆改造及新建体育综合体项目,研究了紧邻深基坑既有建筑物改造与深基坑开挖之间的相互影响,通过大型有限元软件对深基坑开挖和周边既有建筑物“卸载-加载”改造进行模拟,分析了同时进行新建体育综合体深基坑开挖和上海体育馆“卸载-加载”改造两者叠加工况下的相互影响,进一步探讨了深基坑开挖与周边既有建筑物改造同时进行的最优工况。此外,在最优工况的基础上结合基坑被动区加固、围护结构刚度以及两者相互叠加对深基坑和周边建筑物的影响进行深入讨论。结果表明:最不利工况为基坑开挖至第2道支撑时对周边建筑物进行加载改造,在实际施工中应避免出现该工况; 最优工况为基坑完成第1道支撑后对周边建筑物进行卸载改造,并在基坑完成第2道支撑后对周边建筑物加载改造; 在最优工况及其他同等条件下基坑被动区加固对基坑和周边建筑物产生的影响要大于基坑围护结构强度对其产生的影响,研究结果可以为今后类似工程施工提供依据与参考。

Study on Interaction Between Deep Foundation Pit Excavation and Reconstruction of Surrounding Existing Buildings

Based on the reconstruction of Shanghai Gymnasium and Shanghai Natatorium and the new sports complex project, the interaction between the reconstruction of existing buildings close to the deep foundation pit and the excavation of deep foundation pit was studied. The excavation of deep foundation pit and the “unloading-loading” reconstruction of surrounding existing buildings were simulated by large finite element software, and the interaction between them were analyzed. The optimal working condition of deep foundation pit excavation and surrounding existing building reconstruction was further discussed. In addition, on the basis of the optimal working condition, combined with the reinforcement of the passive area of the foundation pit, the stiffness of the retaining structure and the influence of their superposition on the deep foundation pit and surrounding buildings were further discussed. The results show that the most unfavorable condition is the loading reconstruction of the surrounding buildings when the foundation pit is excavated to the second support, which should be avoided in the actual construction. The optimal condition is unloading reconstruction of the surrounding buildings after the first support of the foundation pit is completed, and the loading reconstruction of the surrounding buildings after the second support of the foundation pit is completed. Under the optimal working conditions and other equivalent conditions, the impact of passive area reinforcement of foundation pit on foundation pit and surrounding buildings is greater than that of foundation pit retaining structure strength. The research results can provide basis and reference for future similar engineering construction.