For super section shallow flat tunnel , reasonable flat rate design was crucial to the stability of tunnel surrounding rock and the tunnel construction economy .With Chongqing Metro 5 line super section shallow flat Tunnel as project background , the program with the standard design language APDL of gener-al-purpose finite element software ANSYS to achieve parametric was designed for the 5 different flat ratios of the tunnel .The deformation of tunnel surrounding rock and the force of tunnel structure under 5 kinds of flat ratios were analyzed .With AHP ( analytic hierarchy process ) as the theoretical foundation of multi-objective optimization , target values of excavation area , vault subsidence , ground surface settlement , first support moment , etc.which might affect the stability of flat tunnel were optimized .The analysis data were compared with the site monitoring data .Finally , the optimal flat ratio 0.63 under supported project was put forward .It could be a reference for optimization design of such projects section .%对于超大断面浅埋扁平隧道,合理的扁平率设计对于隧道围岩稳定性和隧道建设的经济性至关重要.采用大型数值分析软件ANSYS,对重庆轨道交通5号线3标超大断面浅埋扁平隧道在5种不同扁平率下的断面形式进行了参数化设计;通过不同扁平率下隧道围岩的变形和隧道结构受力情况进行分析,以层次分析法为优化分析理论基础,对影响扁平隧道结构稳定性的开挖面积、拱顶下沉、地表沉降、初支弯矩等目标值进行优化,并将计算结果与现场监测数据进行对比分析.最终确定了依托工程最优扁平率为0.63,为此类工程断面优化设计提供借鉴.
展开▼
