地铁盾构法隧道正交下穿施工对既有隧道影响分析

Shield Boring of Metro Tunnel Perpendicularly Crossing Underneath Existing Tunnel: Analysis on Influence of Shield Boring on Existing Tunnel

为了探讨新建隧道的施工对既有隧道产生的影响,以西安地铁某区间盾构隧道为背景,采用三维有限元数值计算方法,分析了新建盾构隧道正交下穿施工对地表及既有隧道结构的影响,得到了既有隧道管片位移、内力以及既有隧道上方地表沉降的变化规律。计算分析结果表明:正交下穿盾构隧道施工时,上方既有隧道与地表将会发生较大的不均匀沉降,同时既有隧道衬砌结构发生不均匀侧移和扭转,正交位置附近既有隧道结构下侧出现不同程度的拉应力,需要对正交区域内的地层进行加固。

A running tunnel of Xi ＇ an Metro crosses perpendicularly underneath an existing tunnel. In this paper, the influence of the construction of the running tunnel on the ground surface and the existing tunnel is analyzed by means of 3 D FE numerical calculation method, and the rules of the variation of the displacement and internal force of the segment of the existing tunnel, as well as the settlement of the ground surface above the existing tunnel are obtained. The calculation and analysis results show that differential settlement will occur to the existing tunnel and the ground surface above the running tunnel, differential lateral displacement and turning will occur to the lining structure of the existing tunnel, and tension stress will occur to the crossing section of the two tunnels, where ground reinforcement should be made.