In the heart of Türkiye, a monumental engineering feat is unfolding, one that could reshape how we approach tunnel construction in weak ground conditions. Servet Karahan, a leading expert from Turkish State Railways (TCDD) in Ankara, has spearheaded a groundbreaking study that pits tunnel boring machines (TBMs) against the traditional New Austrian Tunneling Method (NATM). The battleground? The Eşme‐Salihli section of the Ankara‐İzmir High‐Speed Railway Project, where the 13-meter diameter T1 tunnel is being carved through challenging terrain.
Karahan’s research, recently published in ‘Deep Underground Science and Engineering’ (translated from Turkish as ‘Derin Yerbilim ve Mühendisliği’), delves into the intricacies of TBM performance in large-diameter, weak ground conditions. “The selection of the right TBM type and the accurate description of geological and geotechnical conditions are paramount,” Karahan emphasizes. “These factors significantly influence both the selection and performance of TBMs.”
The T1 tunnel, the longest in its section, presented a unique challenge. The weak ground conditions necessitated a meticulous approach. Karahan and his team opted for an earth pressure balanced type TBM, a decision that paid off handsomely. “Additional engineering measures taken before excavation in problematic areas ensured the tunnel was completed within the initially planned timeframe,” Karahan notes. This success story not only highlights the potential of TBMs in challenging conditions but also underscores the importance of pre-emptive engineering strategies.
The implications for the energy sector are profound. As the demand for renewable energy sources grows, so does the need for efficient and reliable infrastructure. Tunnels are crucial for hydroelectric power plants, geothermal energy projects, and even the transportation of energy resources. The ability to construct large-diameter tunnels in weak ground conditions efficiently could revolutionize these sectors, making projects more feasible and cost-effective.
Karahan’s study serves as a beacon for future developments in the field. By providing a comparative analysis between TBM and NATM, it offers valuable insights into the strengths and limitations of each method. This knowledge could guide engineers and project managers in making informed decisions, ultimately leading to more successful and timely completions of tunnel projects.
As the Ankara‐İzmir High‐Speed Railway Project continues to unfold, the lessons learned from the T1 tunnel construction will undoubtedly shape future developments. The energy sector, in particular, stands to benefit significantly from these advancements, paving the way for more sustainable and efficient infrastructure.