地铁车站暗挖通道平行上穿紧邻既有线施工技术研究

Research on construction technology of metro station undercut tunnel parallel to the existing line

以北京地铁 4 号线宣武门站人行通道平行上穿既有线为背景,研究中隔壁法(CRD 法)开挖施工对地下既有线结构受力和形变的影响。采用有限元平面应变力分析模型,研究 CRD 法不同开挖方案对既有线隧道结构的影响,根据数值分析结果对 CRD 法施工进行优化。结果表明,先行开挖紧邻既有线部分可以有效降低掌子面分部开挖卸荷的地层应力,其对既有线隧道结构受力和形变的影响显著低于先行开挖背离既有线部分。

Based on the case study of the pedestrian passage of Xuanwumen station of Beijing metro line 4 up-crossing through the existing line in parallel,this paper studies the infl uence of CRD excavation on the stress and deformation of the existing underground line.The finite element plane strain force analysis model is used to study the infl uence of different excavation schemes of CRD method on the existing tunnel structure,and the construction of CRD method is optimized based on the results of numerical analysis.The results show that the fi rst excavation adjacent to the existing line effectively reduces the ground stress of the tunnel face under partial excavation and unloading,and its influence on the stress and deformation of the tunnel structure of the existing line is significantly lower than that of the first excavated part away from the existing line.