ABSTRACT
A significant issue in the mechanized excavation of deep tunnels in rock mass with various physical, mechanical and geological characteristics, is to ensure that the excavation machine (TBM) does not get stuck due to the occurrence of various geological and geotechnical hazards, especially the squeezing phenomenon. To evaluate the possibility of the occurrence of this phenomenon, it is necessary to carry out comprehensive geological and geotechnical explorations on the host materials before starting tunnel construction. In this paper, the potential of squeezing phenomenon in the route of Sungun Water Conveyance Tunnel (SWCT), Sungun Copper Mine, North-west of Iran, has been investigated.
This tunnel with a length of approximately 5 km has been studied to transfer the water of Sungun Chai River and to prevent the adverse interference of mining operations and the river and ultimately to protect the river. To evaluate the possibility of the phenomenon, the rock mass was studied using in-situ and laboratory investigations and all of the essential geological and geotechnical characteristics such as RQD, RMR, Q and GSI were determined for each of the classified geological (rock) units. After that, the squeezing potential was evaluated by accepted and current experimental and analytical methods. Preliminary investigations showed that in some sections of the tunnel, which have special conditions in terms of geology and the depth of overburden, squeezing is probable, and it is necessary to take appropriate measures for it.
