对于大跨度扁平隧道而言,合理的扁平率设计对于节约成本和减少通风照明费用具有至关重要的作用,因此优化浅埋大跨度隧道的扁平率是隧道设计施工面临的关键问题。首先利用大型有限元分析软件ABAQUS的标准设计语言Python编程,对拟建清远蟠龙浅埋破碎岩体大断面隧道不同扁平率进行参数化设计;研究5种扁平率下隧道结构的稳定性和变形破坏情况,运用层次分析法对影响扁平隧道稳定性的开挖面积、水平收敛、地表沉降和拱顶下沉等目标值进行优化并确定其权向量,提出依托工程条件下的最优化扁平率。该研究成果和方法可为同等条件下隧道工程断面优化设计提供借鉴。
The design of reasonable flat ratios for flat and large span shallow tunnel has very important effect on cost saving and expense reduction for ventilation and lighting.Therefore,optimizing the flat ratios of shallow large-span tunnel is the key problem faced by the tunnel design and construction.Firstly,program with the standard design language Python of general-purpose finite element software ABAQUS to achieve parametric design for the different flat ratios of large-span Panlong tunnel in shallow broken rock mass planned to be constructed in Qingyuan City.Then,the stability and deformation failure of tunnel structure under 5 kinds of flat ratios are researched.Target values of excavation area,horizontal convergence,ground surface settlement,vault subsidence,etc.which affect the stability of flat tunnels,are optimized using the analytic hierarchy process(AHP) and determining their weight vectors.Finally,the optimal flat ratio under supported project is put forward.The results and method of this paper provide reference for the section optimization design of tunnel engineering in equivalent conditions.