接线方案对小净距隧道群的结构选型影响研究

Research on the Influence of Route Scheme in Small Spacing Tunnel Group Structure Selection

以改扩建工程荷坳隧道为研究对象,在对双洞双向八车道叠层盾构隧道与洞外分离式八车道路基之间的隧道接线方案研究的基础上,对YK2+720~YK3+180段460 m范围内隧道结构断面型式、变形及内力分布变化规律等进行了三维有限元数值仿真分析。综合接线方案、制约性边界条件、路线间距、地形地质等因素,对小净距隧道群分段选用了明挖顺做法的错位叠层分离式隧道和错位叠层整体式隧道,暗挖钻爆法的分离式隧道和整体式中墙连拱隧道等组合方案进行了研究,确保了工程建设的安全性和经济性,有效减少了环境影响,研究成果可供类似工程借鉴参考。

Relying on the new-built He’ao Tunnel reconstruction and extension project, on the basis of the study of the tunnel access road scheme that connect the twin tubes with dual 4-lane laminated shield tunnel with the separated eight-lane roadbed outside of the tunnel, the three-dimensional finite element numerical simulation analysis is carried out within the range of 460 m in the YK2+720~YK3+180 section in terms of the type of tunnel cross section, deformation and internal force distribution of the tunnel within the range of 460 m in the +180 section. Based on factors such as access road scheme, restrictive boundary conditions, route spacing, topography and geology, the cut-and-cover method of dislocation laminated split tunnel and dislocation laminated integral tunnel are selected for the small clear distance tunnel group. The combined scheme of the split tunnel and the integral mid-wall multi-arch tunnel ensures the safety and economy of the project construction, effectively reduces the environmental impact, and the research results can be used as a reference for similar projects.