Abstract: The prefabricated structure construction technology of opencut tunnels is not mature in China. Thus, the prefabricated structural system and construction methods of a superlarge crosssection opencut tunnel on Xinsen avenue in Chongqing, China, are being studied to improve the construction quality of tunnel projects. Then, a prefabricated structural system that integrates full prefabrication, castinplace invert, and prefabricated upper structure suitable for opencut highway and municipal large crosssection tunnels is established, and the suggested structure thickness and multilayer waterproof structure scheme are proposed. The analytical and numerical simulation findings reveal the following: (1) The structural mechanical response analysis results of the foursegmentation scheme in castinplace invert and prefabricated upper structures show that the structural stress, displacement, and opening angle of the joints meet relevant requirements and have a certain safety reserve. (2) A prefabricated opencut tunnel construction method with a superlarge crosssection, i.e., sidewall installation, castinplace invert, assemble crown, detailed operation, and soil backfilling, is provided.

Key words: superlarge crosssection opencut tunnel, prefabricated structure, prefabricated construction, opencut structure system