Design and construction of the Geum Ho riverbed tunnel in the 2nd Dae Gu subway construction project: A case history

Abstract

This paper will report design and construction of the Geum Ho Riverbed Tunnel located in the southern part of Korea as a part of the 2nd Dae Gu Subway Construction Project. Total length of the tunnel is about 272m and has been open for public service since the late 2005. The tunnel was the first type of a watertight circular tunnel with large-section in the Korean tunnelling construction history. The tunnel was constructed below the Geum Ho River, where soil and highly fractured rock existed. Therefore, several ground reinforcement methods have been applied to secure the stability of the tunnel and surrounding structures. In order to monitor tunnel movements, a novel three-dimensional (3D) monitoring system that measured the tunnel movements in 3D direction, has been successfully used. In addition, a state-of-the-art automatic monitoring system was adopted to maintain structural safety of the Gang Chang Bridge located adjacent to the tunnel. The movements of the tunnel and the bridge foundation during tunnel construction showed that the movements were insignificant, showing the surrounding ground was effectively reinforced. Some experiences gained from the project will be reported and discussed. (A) This paper was presented at Safety in the underground space - Proceedings of the ITA-AITES 2006 World Tunnel Congress and the 32nd ITA General Assembly, Seoul, Korea, 22-27 April 2006. For the covering abstract see ITRD E129148. Reprinted with permission from Elsevier.