新建地铁车站长距离密贴下穿既有隧道方案比选及实测变形分析

Scheme comparison and measurement analysis of new-build subway station parallel under through existing tunnel in tight contact

城市轨道交通建设中,由于线网规划密集、建设先后顺序不同,新建车站施工不可避免会对既有隧道产生影响。北京地铁15号线奥林匹克公园站下穿既有大屯路公路隧道,如此大断面平行长距离密贴穿越在国内尚属首次。为保证既有大屯路隧道的正常使用,需要选择合理有效的开挖方法。本文采用数值模拟方法,分析PBA八导洞法、PBA六导洞法、暗挖三导洞法以及暗挖四导洞法四种工法施工引起的地表及大屯路隧道结构底板变形。综合考虑既有隧道最大变形、差异沉降、造价和工期,确定暗挖4导洞1、4导洞先开挖法为最优施工方案,实测变形验证了计算有效性。研究结果可为类似工程提供借鉴和参考。

In the urban rail transit construction, due to dense network planning and different construction sequence, the new-build station will inevitably impact existing tunnel. Beijing Olympic Park Station of subway line 15 th under through Datun Road tunnel, such a large cross-section parallel to existing tunnel of long distance and tight contact acrossing is the first time in China. To ensure normal use of the existing Datun Road tunnel, we need choose a reasonable and effective excavation method. In this paper, By use of numerical simulation method, we analyze surface and Datun Road tunnel bottom deformation caused by PBA eight pilot hole method, PBA six pilot hole method, three pilot hole deep excavation method and four pilot hole deep excavation method. Considering the existing tunnel maximum deformation, differential settlement, cost and schedule, determine the four pilot tunnel deep excavated 1,4 pilot hole first method is optimal construction plan. Measured deformation verify the validity of the calculation. The results can provide reference for similar projects.