地铁车站新建安全通道破洞施工对既有结构的影响研究

RESEARCH ON THE IMPACT OF BREAKING CONSTRUCTION OF NEW SECURE CHANNEL IN SUBWAY STATIONS ON EXISTING STRUCTURES

为研究新建安全通道施工对既有车站结构的影响,以北京地铁3号线东四十条(以下简称DSST)站新建安全出口为背景,采用数值模拟对安全通道侧墙破洞施工进行模拟,分析了结构应力和变形变化规律,讨论了破洞分块方案对结构变形的影响,并结合现场监测进行了验证。结果表明:(1)破洞后侧墙结构应力分布发生变化,洞口处出现应力集中,应力最大值相比破洞前增加73.54%;侧墙竖向、水平位移最大值分别为-0.13 mm和0.013 mm;(2)随着分块尺寸的减小,侧墙的水平变形和竖向变形逐渐减小,整体切割方案控制变形的方案最好;(3)综合考虑该工程运输设备功率、现场施工条件和分块体重量等因素,推荐采用方案4的分块方案;(4)DSST站安全口破洞施工完成后,侧墙结构水平变形和竖向变形分别为0.2 mm和0.3 mm,小于报警值。研究成果可为类似车站结构破洞工程提供参考。

To study the impact of the construction of a new safety corridor on existing station structures,with the background of the construction of a new safety exit at the East Forty-third Street Station(referred to as DSST)on Beijing Subway line 3,numerical simulations were used to simulate the construction of the safety corridor.The analysis of structural stress and deformation changes was conducted,and the impact of the segmented hole-breaking scheme on structural deformation was discussed.Validation was carried out in conjunction with on-site monitoring.The results show that:(1)The stress distribution of the rear wall structure changed after the hole-breaking,and stress concentration occurred at the opening,with a maximum stress increase of 73.54%compared to before the holebreaking;the maximum vertical displacement of the side wall is-0.13mm,and the lateral displacement was 0.013mm.(2)As the block size decreased,the lateral and vertical deformations of the side wall gradually decreased,and the overall segmented cutting scheme is the best for controlling deformation.(3)Taking into account factors such as the power of the transportation equipment,on-site construction conditions,and the weight of the segmented blocks,it is recommended to adopt the segmented block scheme of option 4.(4)After the hole-breaking construction of the safety exit at the DSST station is completed,the horizontal deformation and vertical deformation of the side wall structure are 0.2 mm and 0.3 mm,respectively,which are below the alarm value.The research results can provide reference and guidance for similar station structure hole-breaking projects.