• The study analyzes how Tunnel Boring Machine (TBM) operational parameters affect energy efficiency in four different geological formations during the Silvan Tunnel Project. • It highlights the importance of adjusting TBM settings (thrust, torque, RPM, penetration rate) according to specific geological conditions to achieve optimal performance and lower energy consumption. • The research addresses complex real-world issues such as karstic voids, water inflows, and methane explosions, examing TBM efficiency. • The study suggests using advanced technologies like real-time data analytics to further enhance TBM performance in challenging environments. • This work provides a framework for sustainable TBM operation in geologically variable and difficult terrains, supporting more efficient and safer infrastructure development. It also serves as a guide for the alternative Silvan Tunnel, which will be opened under very similar conditions. This study evaluates the impact of Tunnel Boring Machine (TBM) operational parameters on specific energy across four distinct geological formations encountered in the Silvan Tunnel project in Diyarbakır, Türkiye. Real-time field data collected during excavation were analyzed using correlation analyses and graphical representations to assess key operational parameters, including thrust, torque, rotational speed, and penetration rate. The results revealed that geological properties significantly influence specific energy: the Şelmo formation exhibited the highest specific energy due to low penetration rates in soft, clayey ground; Silvan showed high specific energy associated with elevated thrust and torque in hard rock conditions; Midyat achieved the lowest specific energy with high penetration rates despite karstic challenges; and Gercüş demonstrated moderate performance. Adverse conditions such as karstic zones, water inflows, and methane gas explosions further affected excavation efficiency. These findings underscore the necessity of optimizing TBM operational parameters according to geological conditions to improve performance, reduce energy consumption, and enhance safety in complex tunneling environments.
Aydın et al. (Wed,) studied this question.