Sabzkuh tunnel is under construction in Iran. During the course of the project feasibility studies, the importance of the environmental impacts was not sufficiently addressed. Only due to the environmental impacts of the construction the tunnel route was changed. However, in the new routing, the tunnel passage through difficult and complex ground conditions, the interaction of tunnel excavation and groundwater resources and springs, and consequently the environment of the region were not given importance. According to the geological model, the new tunnel route faced various geological hazards, the most important of which were crushed zone and faults with water inrush. These risks made it necessary to choose a TBM with high flexibility. With the start of mechanized excavation in 0+484 km, faced with Solaghan fault and the inability of TBM to cross it, caused it to get stuck. Subsequently, water drainage caused the drying up of Aloqareh spring and dehydration of Shirkoshteh spring and negative environmental impacts in the region. In this regard, the release of TBM was done by construction two by Pass galleries. Finally, due to the problems, TBM was taken out of the tunnel and the tunnel excavation was stopped.
