Abstract: Technical issues include support and settlement control induced by the fourtrack large crosssection tunnel closely crossing beneath the large utility tunnel in weak and waterrich strata are always encountered. As a result, case investigation, scheme comparison and selection, numerical simulation analysis, and onsite monitoring methods are used to investigate the construction technologies and processes, advanced reinforcement, and supporting parameters of the GuangzhouFoshan intercity passing beneath the Huakang road utility tunnel. The results reveal the following: (1) Based on the active deformation control technology, the collaborative support scheme of the pipe roof under utility tunnel, advanced pipe roof at the tunnel arch, horizontal jet pregrouting and waterproofing, and doublelayer lining are adopted, which is the optimal in terms of adaptability, construction period, and cost. (2) The fourtube tunnel is excavated in order of numbers 1, 3, 2, and 4. The cross diaphragm method is used for tunnel numbers 1, 3, and 4, whereas the threebench method is used for tunnel number 2 to control the settlement of the tunnel and the utility tunnel. (3) During the excavation of the tunnel number 1, the settlement and deformation rate of the tunnel and utility tunnel is the largest. (4) Onsite monitoring results show that the settlements of surface, pipeline, utility tunnel, and tunnel crown are all within 5 mm.

Key words: fourtrack tunnel, shallowburied excavation, undercrossing construction, utility tunnel, advanced reinforcement, doublelayer lining, pipe roof, jet grouting pile