In the rugged landscapes of western Syria, the Tishreen Tunnel has long been a critical artery for transportation and energy infrastructure. However, the tunnel’s stability has been increasingly compromised by a phenomenon known as squeezing, where the surrounding rock deforms plastically under high stress, leading to severe structural damage. A recent study published in *Deep Underground Science and Engineering* (formerly known as *Deep Underground Science and Engineering*) sheds light on the causes of these failures and offers innovative solutions that could revolutionize tunnel construction and maintenance in weak rock formations.
Lead author Mohannad Mhanna, a researcher at the Faculty of Civil Engineering at Tishreen University in Lattakia, Syria, and his team have delved into the intricate mechanics of squeezing-induced failures. Their work not only provides a detailed analysis of the Tishreen Tunnel’s structural issues but also proposes a robust framework for evaluating and mitigating such risks in future projects.
The study begins by examining the empirical data of the Tishreen Tunnel, which has suffered from buckling and spalling of side walls, floor heave, and extreme convergence, ultimately leading to the failure of the tunnel lining. “The squeezing phenomena can lead to severe loads in deep tunnels, especially in the presence of a low ratio of surrounding rock strength to overburden pressure,” Mhanna explains. This observation underscores the critical need for accurate assessment and effective support systems in weak rock environments.
To tackle this challenge, Mhanna and his team developed a numerical model using a time-dependent constitutive model to simulate the long-term response of the tunnel. The Burger viscoplastic model, in particular, proved to be highly effective in capturing the deformation and creep behavior of the squeezing ground. “The Burger viscoplastic model simulates effectively the resulting deformation and creep behavior of squeezing ground,” Mhanna notes, highlighting the model’s accuracy and reliability.
The research also proposes a comprehensive reinforcement scheme to address the tunnel’s structural issues. This includes the use of steel ribs, grout injection, ground anchors, and a new lining of reinforced concrete. The combined heavy support system demonstrated significant control over squeezing deformation, ensuring the tunnel’s serviceability and longevity.
The implications of this research extend far beyond the Tishreen Tunnel. In the energy sector, where underground infrastructure is crucial for transportation, hydroelectric power, and resource extraction, understanding and mitigating squeezing phenomena can lead to more stable and cost-effective projects. “Using a combined heavy support system can provide efficient control over squeezing deformation and maintain the serviceability of the tunnel under study,” Mhanna states, emphasizing the practical applications of their findings.
As the energy sector continues to expand and diversify, the need for robust underground infrastructure will only grow. The insights gained from this study could shape future developments in tunnel construction, particularly in regions with weak rock formations. By adopting advanced modeling techniques and innovative support systems, engineers can ensure the stability and longevity of critical underground infrastructure, ultimately driving progress and sustainability in the energy sector.
In the words of Mohannad Mhanna, “This study not only addresses the immediate challenges faced by the Tishreen Tunnel but also paves the way for safer and more efficient tunnel construction in the future.” As the energy sector continues to evolve, the lessons learned from this research will be invaluable in building a more resilient and sustainable underground infrastructure.