Comparative Study of Construction Methods for Deeply Buried Soil Tunnels

Deep-buried soil tunnels in weak rock strata often face severe risks, such as collapse and large deformation, making the rational selection of construction methods critical. Using a tunnel project in Baotai District, Yan’an City as a case study, this research compares the three-step method, three-step temporary inverted arch method, double-side wall pilot tunnel method, and CD method. By combining a numerical simulation with field monitoring, the study evaluates surrounding rock deformation and support stress characteristics. Results show that while deformation differences among methods are small, the double-side wall pilot tunnel method offers optimal deformation control, and the three-step temporary inverted arch method provides the best stress distribution and meets the specification requirements. Notably, only the three-step method shows anchor bolt stress exceeding the design limits. Considering safety, efficiency, and cost, the three-step temporary inverted arch method is recommended. The strong agreement between simulation and monitoring data highlights the model’s reliability and its value in guiding tunnel design and construction optimization.