南京古平岗地铁基坑围护结构监测及数值模拟分析

MONITORING AND NUMERICAL SIMULATION ANALYSIS OF FOUNDATION PIT SUPPORTING STRUCTURE IN NANJING GUPINGGANG METRO

为了研究地铁基坑开挖变形对工程的安全性及周围环境的影响,以南京古平岗地铁站基坑围护结构监测数据为依据,结合有限元计算软件进行数值模拟分析,探讨了基坑开挖过程中围护结构桩墙的水平位移、围护结构桩顶的沉降以及基坑周边地表的沉降变形。结果表明:目前基坑围护结构桩墙的水平位移、围护结构桩顶的沉降、基坑周边地表的沉降变形的实测值与模型计算结果相符,均未超过基坑监测预警值,处于安全状态;基坑围护结构的变形向内部倾斜,最大水平位移发生在围护结构桩墙约中上部处;围护结构桩顶的沉降随时间逐渐增加,但出现几次小规模向上的反弹;地表沉降量整体趋势先增大后减小,最大沉降点发生在距离基坑约10 m处。

To study the impact of subway foundation pit excavation deformation on the safety of the project and the surrounding environment,based on the monitoring data of the foundation pit support structure of Nanjing Gupinggang metro station and combined with finite element calculation software for numerical simulation analysis,the horizontal displacement of the pile wall of the supporting structure,the settlement of the supporting structure,and deformation of the surrounding ground surface of the foundation pit were discussed during the excavation of the pit.The results show that the current horizontal displacement horizontal of the pile wall of the supporting structure,the settlement of the supporting structure,and deformation of the surrounding ground surface of the foundation pit are consistent with the calculation results of the model,which didn't exceed the monitoring and early warning value of the foundation pit,indicating that it is in a safe state.The deformation of foundation pit supporting structure is inclined to the inside,and the maximum horizontal displacement occurs at about the middle and upper part of the supporting structure.The settlement of the supporting pile gradually increases with time increasing,but there are several small-scale upward rebounds.The overall trend of surface settlement is to increase first and then decrease.And the maximum settlement point occurs at about 10 m away from the foundation pit.