特大跨径(2×4车道)“半明半暗”双连拱隧道设计

Design of a partially buried double-arch tunnel with super-large span(2×4 lanes)

罗汉山隧道是福建省福州长乐国际机场高速公路二期工程中的一座双向八车道(2×4车道)双连拱隧道,开挖跨径宽达41.6 m(连拱开挖总宽度),是我国目前跨径最大的双连拱隧道。隧道进口位于地形严重偏压地段,为贯彻"‘零’开挖"理念,并确保施工安全,避免洞口"大挖大刷"形成高边坡、仰坡,隧道进口段采用"半明半暗"的双连拱隧道进洞方法。文章从设计的角度,对隧道不同的进洞方案进行分析、比较,并重点叙述了特大跨径"半明半暗"双连拱隧道的设计与计算。

Luohanshan tunnel is a two -way 8 -lane double -arch tunnel （2x4 lanes） on the 2nd phase express way project of Changyue International Air port of Fujian province. The overall excavation width of it reaches 41. 6m, the longest span of double - arch tunnel in China to date. Entrance section of the tunnel is situated in such topography that will cause severe uneven pressure onto the tunnel. Adhering to the concept of zero excavation＇to avoid big digging and stiff side and front slopes, the entrance was designed as a partially - buried double - arch tunnel. The paper analyzed and compared different options for the entrance and described in detail the design and calculation of the super- large span partially- buried double -arch tunnel.