ObjectiveAddressing technical challenges in integrating sewage pipelines into underground utility tunnels during China's accelerated urbanization, including gravity-flow slope gradient matching difficulties, prominent pipeline crossover conflicts, and insufficient durability in highly corrosive environments. This study systematically explores optimized design solutions using a new town construction project in Zhengzhou City as a representative case.MethodsFor slope gradient cooperative control, a coordinated design harmonizing utility tunnel longitudinal slope, sewage pipe slope gradient, and road slope gradient are established, with finite element analysis optimizing support pier spacing and structural parameters. For corrosion protection, an independent sewage compartment layout employs ductile iron pipes lined with epoxy ceramic coatings combined with fiberglass-reinforced plastic-encapsulated inspection well nodes, creating a "rigid substrate + flexible protection" composite anti-seepage system. The intelligent safe system integrates variable-frequency ventilation, distributed toxic gas monitoring, and liquid-level-linked drainage devices to form a multi-dimensional protection mechanism.ResultsThe project realizes that the longitudinal slope gradient of gravity flow sewage pipeline is controlled within ±0.1% accuracy of deviation from design. The leakage of the pipeline corridor is reduced to 0.05 L/(m²·d). Temperature fluctuation in the chamber in a single day is no more than 2 ℃. Methane volume fraction is controlled within 1%, which is below the explosion threshold, and hydrogen sulfide mass concentration is controlled within 5 mg/L. The project significantly reduces the accident rate of pipe burst and leakage caused by corrosion and sedimentation of sewage pipes.ConclusionThe developed "three-dimensional slope gradient coupling design-composite anti-corrosion system-intelligent operation and maintenance" framework effectively resolves technical bottlenecks for wastewater integration in Zhengzhou's alluvial strata utility tunnels. Its spatially adaptive design, long-term anti-corrosion techniques, and smart resilience management model provide a replicable paradigm for utility tunnel construction in alluvial plains.