LAUSR

Because of the harsh environment around city subways and the typically poor geological conditions, it is often difficult to ensure the stability of a tunnel, which makes it prone to collapses and other accidents. The influence of multiple factors on tunnel stability was analyzed under the same geological conditions and environmental factors by using a three-dimensional numerical simulation. Taking into account the objective environment and manual operation and other factors, construction sequence, support closure time, and reinforcement area and parameters were chosen as the main factors affecting the tunnel stability. Finally, based on ground deformation, tunnel convergence deformation, and surrounding soil stress as evaluation indicators, a fuzzy analytic hierarchy process (FAHP)-gray correlation degree-technique for order performance by similarity to ideal solution (TOPSIS) model was established. It was found that the higher the relative closeness of the construction parameter combination, the greater the tunnel stability. The best combination of construction parameters was applied to the Tiantongyuan Station project of Beijing Metro Line 17. All geological conditions being equal, reasonable selection of construction parameters can ensure optimal tunnel construction stability, reduce construction risks, and support sustainable tunnel development. In addition, the FAHP-gray correlation degree-TOPSIS method achieved multi-index evaluation of tunnel stability, which provides practical guidance for the construction of similar projects.