并行小净距隧道下穿机场滑行道开挖间距优化研究

Optimization of Excavation Interval for Parallel Tunnels with Small Spacing Undercrossing Airport Taxiway

随着地下空间进一步被开发和利用,经常出现新建隧道穿越已有建筑物的工程项目,甚至一些地铁隧道、交通隧道不得不穿越机场区域。又由于经济、环保及地形限制等因素,小净距隧道备受推崇。隧道在开挖过程中将会遇到软弱围岩、岩溶等地质环境的影响,从而给隧道施工与运营带来很大的困难和风险。依托某机场隧道下穿滑行道工程,通过数值模拟上下台阶预留核心土法(采用“桩托板”防护体系)开挖施工过程,设置6个不同的工况,分别为左线超前右线0、1B、2B、3B、4B、5B(B为隧道跨度),与先左后右开挖次序(工况一)对比,对滑行道加固效果、道面沉降控制作用和隧道施工后飞机滑行通过隧道上方时二次衬砌结构的受力特征进行分析。

With the further development and utilization of underground space,there are often engineering projects where new tunnels pass through existing buildings from below,and even some subway tunnels and traffic tunnels have to pass through the aircraft movement area.Due to some factors such as economy,environmental protection and terrain limitations,tunnels with small spacing are highly regarded.The excavation of the tunnel may be influenced by soft and weak surrounding rocks,karst and other geological environments,which will bring great difficulties and risks to the construction and operation of the tunnel.In this study,based on a certain tunnel project undercrossing the airport taxiway,excavation construction is simulated using the benching tunneling construction method with core soil reserved(using the“pile supporting plate”protection system)through numerical analysis.Six different working cases are set,namely,the left line leading the right line by 0,1B,2B,3B,4B,5B(B is the tunnel span),and compared with the excavation sequence from left to right(working case 1),the reinforcement effect of the taxiway and the control effect of taxiway surface settlement are analyzed as well as regarding stress characteristics of the secondary lining structure when aircraft taxiing above the tunnel after tunnel construction.