Influence of the fault zone in shallow tunneling: A case study of Izmir Metro Tunnel

摘要

Today, there is a great need for larger underground spaces for various purposes and hence, construction of new metro tunnels has become a necessity to meet the demand in urban life in spite of certain ground related difficulties such as fault zones, altered and fractured rock mass and ground water. This study has aimed at investigating the risky areas around a shallow metro tunnel in weak, faulted rocks and determining the effects of tunnel behavior on the structures on ground surface. Therefore, an attempt has been made to determine the risky areas on the line of the tunnel by field observations, laboratory work and computer modeling. Later, the data obtained from computer models have been compared to which obtained from in situ measurements. The results from modeling and in situ measurements were interpreted considering the current status of superstructure and the differences between pre- and post-excavation states in the ground. Finally the data obtained from the modeling analysts and measurements provided the necessity of strengthening the already used support system for the safety of the buildings on surface. Shortening the application ranges of the rock bolts, use of face nails with application of umbrella arc and ietarout methods are among the precautions to be taken.