The research focused on the Hankou Tunnel, a deep-lying section of the challenging Xinjin Expressway spiral tunnel group. To find the best way to support the tunnel walls, the research team turned to advanced computer simulation technology (using the ABAQUS platform). Researchers created detailed digital models to simulate the entire construction process from start to finish. Published in Smart Construction, the findings offer crucial reference for designing more effective support systems for other deep mountain tunnels built in similar rock formations.
Nowadays mountain tunnels are playing an increasingly critical role in modern transportation systems, leading to the continuous emergence of numerous long, deep-buried mountain tunnel projects. However, there remains ongoing debate about how effectively standard ground anchors work in tunnels and their true supporting role. Meanwhile, although pre-support pipes are commonly used for advance reinforcement, there has been little research into how they perform when combined with ground anchors.
To address this gap, a research team led by Professor Dechun Lu from Beijing University of Technology developed highly accurate computer simulations that replicate the entire tunnel excavation process. Using these models, the team compared the effectiveness of ground anchors and pre-support pipes, both individually and in combination, offering new evidence to help optimize support strategies in challenging ground conditions.
Professor Lu explained: "Our model was carefully validated by comparing its results with actual data from the construction site, ensuring that it reliably reflects real-world engineering conditions."
After validating the model against real-world field measurements, the research team closely examined multiple indicators of deformation and mechanical response. These included the settlement of the tunnel crown, the inward horizontal movement of the surrounding rock and primary support, the development of stress fields in the rock mass, and the identification of potential plastic failure zones.
Graduate researcher Xiaoyu Liu explained: "We conducted a thorough and detailed analysis of the simulation results. This not only focused on the final stresses and deformations after tunnel excavation was complete but also investigated how these values changed throughout the construction process and at each major step."
Integrating engineering cost calculations with their simulation findings, the researchers conducted a detailed comparative analysis of how well ground anchors and pre-support pipes performed in this deep section of the Hankou Tunnel.
The study concluded that, for the geological conditions examined, a support system combining primary lining, secondary lining, and ground anchors was sufficient to effectively control rock stress and deformation. Pre-support pipes can serve as a valuable extra step in particularly weak or fractured zones, helping to pre-stabilize the ground before the main excavation passes through.
This approach provides engineers with a flexible strategy: use the combined lining and anchor system as the standard, and add pre-support pipes specifically where the ground conditions are poorest.
While the team acknowledges that certain details in the simulation models could be further refined, this research represents an important step toward safer and more reliable reinforcement methods for mountain tunnels.
This paper "Comparison and selection of support schemes for deep buried soft broken section of Xinjin expressway spiral tunnel—a case study of Hankou tunnel" was published in Smart Construction (ISSN: 2960-2033), a peer-reviewed open access journal dedicated to original research articles, communications, reviews, perspectives, reports, and commentaries across all areas of intelligent construction, operation, and maintenance, covering both fundamental research and engineering applications. The journal is now indexed in Scopus, and article submission is completely free of charge until 2026.
Lu D, Liu X, Xu H, Guo C, Du . Comparison and selection of support schemes for deep buried soft broken section of Xinjin expressway spiral tunnel—a case study of Hankou tunnel. Smart Constr. 2026(1):0002, https://doi.org/10.55092/sc20260002 .
