基于目前国内外对大断面通航隧道的设计和施工尚无可参照的标准规范，以富春江七里泷航道通航隧道工程项目为依托，分析满足隧道水下断面形状要求、水上部分建筑界限要求以及通航隧道安全保障的措施要求，并结合围岩及隧道结构的受力特点，应用最优化方法及相关分析计算，对隧道内轮廓进行优化设计，提出了满足Ⅳ级单线航道的大断面通航隧道断面，综合经济性及结构受力角度合理性考虑推荐采用曲墙式断面。

So far there is no standard at home and abroad that can be referred to in the design and construction of large crosssection waterway tunnels. In the paper, the design of the crosssection of Fuchunjing waterway tunnel is studied. The requirements for the crosssection of the underwater part of the waterway tunnel, the construction clearance of the abovewater part of the waterway tunnel and the navigation safety guarantee measures are analyzed. Optimization design is made on the inner contour of the waterway tunnel by means of optimization method and analysis, considering the mechanical characteristics of the surrounding rock and the tunnel structure. The crosssection of largesized waterway tunnel that can meet the requirements of Grave IV single shipping lane is proposed. It is suggested that the crosssection with curvedwalls should be adopted, considering the economic efficiency and structure force.