深基坑开挖对邻近既有地铁站变形监测分析

Analysis of deformation monitoring of adjacent existing subway stations during deep excavation of foundation pits

随着新一线城市的快速发展,不可避免出现新建建筑物邻近地铁站的情况,新建建筑物深基坑开挖会对地铁站及地铁的运行产生一定的安全影响。本文以中原科技城科技创新园项目深大基坑开挖邻近郑州轨道交通4号线龙湖中环北站及附属结构为例,通过对地铁车站及基坑周边边坡进行现场监测,得到了地铁车站出入口、地铁车站主体及基坑周边边坡的监测数据,并对监测数据进行深入的分析。研究结果表明:双排桩支护对基坑边坡、地铁车站出入口、车站主体等建构筑物有良好的支护效果;土方开挖过程中,由于土体卸载造成地铁车站出入口和地铁站主体隆起,而基坑周边边坡由于土体扰动发生沉降;在土方开挖至筏板时,地铁车站出入口、车站主体及基坑周边竖向及水平变形达到最大值,随着地下室结构的施工变形逐渐减小;地铁车站出入口、车站主体变形值与控制值比值均小于0.6,预警监测等级为A级,可正常进行外部施工。

With the rapid development of new first tier cities,it is inevitable that new buildings will be built near subway stations.The excavation of deep foundation pits for new buildings will have a certain safety impact on the operation of subway stations and subways.This article takes the excavation of deep foundation pits for the Zhongyuan Science and Technology City Innovation Park project,which is adjacent to the Longhu Zhonghuan North Station and its affiliated structures of Zhengzhou Metro Line 4,as an example.Through on-site monitoring of subway stations and the slopes around the foundation pits,monitoring data of the entrance and exit of subway stations,the main body of subway stations,and the slopes around the foundation pits are obtained,and in-depth analysis of the monitoring data is conducted.The research results indicate that double row pile support has a good support effect on construction structures such as foundation pit slopes,subway station entrances and exits,and station main bodies;During the excavation process,due to soil unloading,the entrances and exits of the subway station and the main body of the subway station are raised,and the slopes around the foundation pit experience settlement due to soil disturbance;When excavating to the raft slab,the vertical and horizontal deformation of the subway station entrance and exit,the station body,and the surrounding area of the foundation pit reaches its maximum value,and gradually decreases with the construction deformation of the basement structure;The ratio of deformation values to control values at the entrance and exit of the subway station and the main body of the station is less than 0.6,and the warning monitoring level is A level,which allows for normal external construction.