Abstract: The square arched structure is widely used in the construction of urban utility tunnel projects in China because of its high space utilization rate. However, there are few studies on the bearing characteristics, mechanical behaviors, and design methods of square arched corrugated steel structure. Therefore, the analytical bending moment solution of the square arched corrugated steel utility tunnel is deduced using the basic theories of structural mechanics and geotechnics, as well as the relevant codes, and the effectiveness of the analytical solution is validated by a two-dimensional plane strain model and a three-dimensional finite element model that accounts for variations of cover depths. Moreover, comparison between the analytical solution and the numerical results is conducted to determine the applicable cover depths range of the analytical solution. Based on the analytical solution of the bending moment, the section parameters of the utility tunnel are optimized, providing recommended values. The results reveal the following: (1) The analytical bending moment solution agrees well with the numerical calculation, with a maximum error of 5.79%. (2) The analytical solution is applicable only when the cover depth is lower than 10 m. (3) Numerical results indicate that the rise-span ratio and top arch span-side arch span ratio are in the range of 0.6－0.8, and the distribution of structural bending moment is rational, guaranteeing structural safety.

Key words: square arched corrugated steel utility tunnel, analytical solution of bending moment, finite element analysis, cover depth, section parameter optimization