地铁车站深基坑降水对围护结构影响数值模拟分析

Numerical Simulation Analysis on the Influence of Precipitation on Envelope Structure of Deep Foundation Pit in Subway Station

本文以南通轨道交通1号线为依托,采用有限差分软件FLAC^(3D)就地铁车站深基坑降水对围护结构影响进行数值分析。结果表明,地表最终沉降值为24.9 mm,开挖施工、基坑降水对距离坑边0~20.5 m范围具有较大影响;最大桩体水平位移为16.1 mm,桩体变形能达到基坑安全开挖要求;完成第一次降水后,距坑边10.5 m部位出现最大沉降。在距离围护桩约5.5 m处地表具有最大沉降量计算值,为24.5 mm,而同一部位地表沉降监测值为26.4 mm。围护桩桩体水平位移数值模拟结果为14.9 mm,监测值为16.7 mm。第三道钢支撑区域出现的桩身变形与整体变形趋势相一致。

Taking Nantong Rail Transit Line 1 as the research object,this paper uses finite difference software FLAC^(3D) to simulate and analyze the impact of precipitation of deep foundation pits in subway stations on the envelope structure.The results show that the final surface settlement is 24.9 mm,and the excavation construction and precipitation of the foundation pit have a great influence on the settlement within 0~20.5 m from the edge of the pit;the maximum horizontal displacement of the pile body is 16.1 mm,and the deformation of the pile body can meet the requirements of safe excavation of the foundation pit;after the first precipitation,the maximum settlement occurs at 10.5 m from the edge of the pit.The maximum settlement value of the surface is 24.5 mm at about 5.5 m away from the enclosure pile,while the surface settlement monitoring value is 26.4 mm at the same location.The numerical simulation value of the horizontal displacement of the enclosure pile body is 14.9 mm,and the monitoring value is 16.7 mm.The deformation of the pile body at the third steel support area is consistent with the overall deformation trend.