An introduction on the increasing usage of precast concrete arch tunnel in Korea

Abstract

Applying cast-in-place concrete structure when constructing a cut and cover tunnel results in a lot of construction time and cost. In this case, it is possible to construct the underground structure economically and quickly using the precast concrete arch system considering the soil-structure interaction. In the past, engineers were mainly designing a cut-and-cover tunnel with thick and rigid structures. Thus, many engineers thought that thin precast arch structures could only be applied in very limited cases such as the low backfill cover and the symmetrical earth pressure condition. However, due to the development of geotechnical F.E.M. software and understanding of the soil-structure interaction, various kinds of underground structures can be designed using precast concrete arches. This paper introduces the application of various precast concrete arch tunnels applied to underground structures in Korea. The list of application cases is as follows: (i) Precast concrete arch tunnel applied to the tunnel length of 2,000 m under the water level; (ii) Examples of application with asymmetric earth pressure load condition; (iii) Underground protection structures.