北京地铁19号线新草区间洞桩法施工工序优化研究

Study on the construction process optimization of tunnel pile method in Xinfadi-caoqiao section of Beijing Metro Line 19

为提高洞桩法在地铁区间隧道施工过程中的安全性,本文依托北京地铁19号线新草区间暗挖段工程,利用有限差分数值计算软件对洞桩法施工暗挖段导洞开挖及桩施工进行工序优化研究。对比分析了六种施工工序后地表沉降变形的影响规律。研究结果表明:路面沉降极值均出现在二衬拱顶正上方位置,且六种工况中以工况五的-19.2mm为最小。采用工况五,即先开挖中间小导洞、随即施作桩基冠梁,再开挖两侧导洞的施工顺序,可保证本工程施工的安全有序进行。研究成果可为浅埋暗挖多导洞的洞桩法施工部序提供有力参考。

In order to improve the safety of hole pile method in subway tunnel construction,based on the project of Xincao section of Beijing Metro Line 19,this paper uses the finite difference numerical calculation software to optimize the process of pilot tunnel excavation and pile construction.The influence law of surface settlement deformation after six construction processes is compared and analyzed.The results show that:the extreme value of pavement settlement appears directly above the second lining vault,and the minimum value is-19.2mm in case 5.In case 5,the construction sequence of excavating the middle pilot tunnel first,then constructing the pile cap beam,and then excavating the pilot tunnels on both sides can ensure the safe and orderly construction of the project.The research results can provide a strong reference for the construction sequence of shallow buried multi pilot tunnel pile method.