软土地层大断面矩形隧道结构施工力学行为监测与分析

发布时间：2018-04-04 22:20

本文选题：软土地层　切入点：大断面矩形隧道　出处：《隧道建设》2017年S1期

【摘要】：为确保软土地层大断面矩形下穿隧道施工时的安全,以昆明轨道交通3号线区间浅埋暗挖隧道为依托,采用中导洞法,将全断面分成6个导洞按照先中间后两侧、先上面后下面的顺序施工,并采用现场监测和理论分析的方法对隧道支护结构受力进行全过程监控与分析。监测分析结果表明:在矩形隧道顶部与侧面设置超长大管棚条件下,隧道初期支护内力变化较小,因受不同导洞开挖扰动影响,隧道结构底部出现受拉现象,导洞(2)(中下导洞)、导洞(4)(左下导洞)和导洞(5)(右上导洞)对整体结构安全起决定性作用,需要重点监控;最大围岩接触应力出现在导洞(4)(左下导洞)底部,隧道4个角的围岩应力明显大于其他部位,需要加强隧道底部基础注浆,以提高地基承载力;临时支护应力受不同导洞开挖影响出现明显的波动,很好地反映各导洞施工过程中围岩应力释放的特征。
[Abstract]:In order to ensure the safety of large cross section rectangular underpass tunnel in soft soil, based on the shallow excavation tunnel of Kunming Rail Transit Line 3, the whole section is divided into 6 sections according to the first middle and the second side.First, the sequence of construction above and below, and the method of field monitoring and theoretical analysis is used to monitor and analyze the force of the tunnel support structure in the whole process.The results of monitoring and analysis show that under the condition of super-long pipe shed at the top and side of the rectangular tunnel, the initial supporting internal force of the tunnel changes little, and the bottom of the tunnel structure appears tension phenomenon because of the disturbance caused by the excavation of different guide holes.The guide tunnel has a decisive effect on the safety of the whole structure and needs to be monitored emphatically. The maximum contact stress of surrounding rock appears at the bottom of the guide tunnel (left lower guide tunnel).The surrounding rock stress of the four angles of the tunnel is obviously larger than that of the other parts, so it is necessary to strengthen the grouting at the bottom of the tunnel to improve the bearing capacity of the foundation, and the stress of temporary support is obviously fluctuated by the excavation of different guide holes.The characteristics of stress release of surrounding rock in the construction process of each guide tunnel are well reflected.
【作者单位】：中铁四局集团城市轨道交通工程分公司;
【分类号】：U455.4

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