地铁盾构隧道下穿既有地下人行通道建筑结构影响分析

Influence of Metro Tunnel Excavation on Existing Underground Passage Building Structure

为预测常州地铁1号线近距离穿越沪宁城际铁路常州站某出站地下人行通道的影响,本文利用FLAC 3D对地铁隧道左、右线分步开挖过程进行模拟,对比研究有、无出站地下人行通道条件下地层所受影响,分析出站地下人行通道的变形及应力影响分布情况。计算结果表明:出站地下通道的存在引起了较明显的“阻隔”效应,使得不同深度地层沉降规律不同,引起地表出现沉降不均匀现象,最大沉降值为11.27 mm;隧道开挖主要造成地下通道的倾斜、扶梯通道底板变形以及扶梯通道与地下通道接口出现差异变形等;隧道贯通对出站地下通道的应力变化影响较小,最大值为20.63 MPa。为防止应力集中,施工时仍需重点监测地下通道与扶梯通道右侧接口处以及扶梯通道右侧出口等位置。

To predict the influence of Changzhou metro line 1 through an underground passage in Shanghai-Nanjing intercity railway station,using the FLAC 3D to simulate the metro tunnel excavation process,studied the influence of strata with or without the existing station underground passage,analyzed the deformation and stress distribution of underground gallery.The results show that the existence of the underground passage caused an obvious barrier effect,and the settlement of different strata is different.The maximum settlement value is 11.27 mm;Tunnel excavation is mainly caused by the tilt of the underground passage,the deformation of the floor of the staircase and the interface between the escalator and the underground passage.The influence of tunnel excavation on the stress change of the underground tunnel is small,and maximum stress value is 20.63 MPa.To prevent stress concentration,it is still necessary to focus on monitoring the right interface of the underpass and the right exit of the escalator during tunnels construction.