Design and construction of a road tunnel in Korea including application of the Decision Aids for Tunneling – A case study

Numerous tunnels have been built and new tunnels are planned in Korea. As the demand for roads and railways increases, additional tunnels are needed because of the mountainous topography of Korea. This paper presents one such tunnel, the Sucheon tunnel, a road tunnel consisting of two parallel tubes approximately 1900 m long. After a brief presentation of the project with emphasis on the geologic conditions the major part of the paper is devoted to an application of the Decision Aids for Tunneling (DAT). The DAT are a computer-based tool with which tunnel construction cost and time can be computed considering uncertainties in geology and construction processes for the given tunnel. The DAT have been tested and applied successfully in tunnels in Korea. In this paper, the DAT are applied in two phases: Phase I before construction and Phase II during construction. Phase II is based on updated geologic conditions as they were encountered during construction. The paper first discusses the effect of major uncertainties in Phase I and then compares the results of Phases I and II; in the latter an encompassing and a simplified description of geology are used and the results are very similar.