为研究适用于城市核心区的最优沉管隧道的结构类型和预制方案，以广州市琶洲西隧道工程为例，对城市核心区沉管隧道结构类型及预制方案进行综合比选分析，分别对比钢壳组合结构（二次浇筑混凝土）、钢壳组合结构（一次浇筑混凝土）、钢筋混凝土结构（新建干坞）、钢筋混凝土结构（移动干坞）4种方案的优缺点，最终选择钢壳组合结构（二次浇筑混凝土）的方案。采用小截面双层钢壳混凝土沉管隧道的结构型式，结合长距离高干舷运输、二次浮态浇筑混凝土等先进施工工艺，可以有效地解决城市核心区域沉管隧道建设工程中干坞用地紧张等困难，同时有工期短、河道疏浚少、工程质量可靠、环保等优势，在内河沉管隧道中有广泛的应用前景。

A case study is conducted on the Pazhou west tunnel project in Guangzhou, China, and the structural type and prefabrication scheme of immersed tunnels in urban core areas are comprehensively compared to select an optimal structural type and prefabrication scheme of immersed tunnels in the urban core area. Then, the advantages and disadvantages of steelshell composite structure (secondary pouring concrete), steelshell composite structure (primary pouring concrete), reinforced concrete structure (new dry dock), and reinforced concrete structure (mobile dry dock) are analyzed and compared. The final scheme is selected as the steelshell composite structure (secondary pouring concrete). The difficulties of dry dock land shortage in the construction project of immersed tunnel in the urban core area can be solved by adopting the structural type of smallsection doublelayer steelshell concrete immersed tunnel and employing advance construction technologies, such as longdistance high freeboard transportation and secondary floating concrete pouring. The method adopted has the advantages of a short construction period, less river dredging, reliable engineering quality, and environmental protection, which will be widely used in the immersed tube tunnel under inland rivers.