摘 要
随着城市快速经济的增长及人口的高度集中，城市隧道及地下工程的修建日益迫切。但是城市隧道的建设面临一系列的问题，软弱围岩就是其中之一。所以本次设计的主要目的就是解决目前在软弱围岩隧道施工中的各种难题，控制隧道在开挖过程中的变形和围岩松弛，减少施工临时支护，防止坍塌，改善和提高现有技术水平。
本设计题目是青岛市地铁一期工程（3号线）中山公园站2号风道支护，主要设计内容有：二次衬砌荷载的计算和配筋，初期支护设计，施工管理，监测方案等。
为有效控制隧道工程安全风险，避免或减少坍方事故发生，应以“充分调动围岩的承载能力，有效控制围岩变形和松弛”为设计理念，按新奥法原理进行软弱围岩隧道设计。软弱围岩隧道具有自稳差、易坍塌的工程特点，因此在这类围岩中施工必须根据隧道开挖后可能产生的变形实态，采取相应应对措施，如：采取控制地表面下沉及拱脚下沉的技术；大管棚超前支护等 。 关键词：软弱围岩隧道；新奥法；变形；施工管理
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Abstract
With rapid growth of urban economy and concentration of population, it becomes urgent to construct urban tunnel and underground projects. But urban tunnel’s construction faced a lot of problems; soft rock is just one of them. So the main purpose of this design is to deal with the different problems in construction of tunnels in soft rock, control the deformation and the relaxation of wall rock in tunnel excavation process, reduce the construction temporary support, to prevent collapse, improving and enhancing the technical levels of existing.
The designed topic is Qingdao subway (line 3) zhong shan park station 2# ventilation tunnel support, the paper includes: lining load calculation; primary support design; reinforcement calculation of the secondary lining of tunnel; construction management; the monitoring plan; etc.
For effective control of tunnel construction safety risk, avoid or reduce a cave-in occurred, we should use The New Austrian Tunneling Method in design of tunnels in soft rock based on the design method—fully mobilize the bearing capacity of wall rock, to effectively control it’s deformation and relaxation. The soft and weak rock tunnel must be based on the tunnel excavation in this type of surrounding rock deformation may be produced after the solid state and adopt corresponding technical countermeasures, such as: Take the control of ground surface
subsidence and the arch feet sink technical countermeasures and so on; Pre-grouted big tube canopy.
Keywords: Tunnels in soft rock; Support in advance; New Austrian Method; Construction management