How the complex geology of Turkey affected the performance of different TBMs - lessons learnt
The use of tunnel boring machines is increasing tremendously in Turkey. However, the complexity of geology causes important failures and inefficiency in mechanical excavation process. In this paper, the problems of frequent changes in geology in Kadikoy-Kartal metro project, and closing the openings; the change of all cutters in Beykoz tunnel in zones having different geological characteristics; squeezing problems in Bilecik-Kosekoy, Uluabat and Kargi tunnels; face collapses in different tunnels; methane explosion in Selimpasa tunnels; the excessive cutter wear in TBMs worked in Marmaray Project and Beykoz Tunnel; the difficulty of using slurry machines in Istanbul; will be explained in detail. The causes and effects of problems and remedial works will be explained in detail to overcome possible future problems. Case studies were carried out within scope a research project sponsored by Turkish Scientific and Research Council (TUBITAK, project No 112M859).