Publication Abstract

Proceedings of the Deep Mixing 2015 Conference, (DFI)

The Design of a Partial Depth Cement Deep Mixing (CDM) Foundation for an Immersed Tunnel
P. Jackson, COWI A/S, Denmark; J. S. Lee, Daewoo E&C, Korea, Republic of; K. R. Massarsch, Geo Risk & Vibration Scandinavia AB, Sweden

A 3.2 km long immersed road tunnel forms part of the Busan-Geoje Fixed Link in South Korea, which connects Korea's second largest city Busan, with the island of Geoje. To ensure the water tightness of the joints of the segmental tunnel structure and to limit the forces in the shear keys, the differential settlements have to be limited. This was achieved by extensive soil improvement of the marine clay below the tunnel with cement deep mixing (CDM) and sand compaction piles (SCP). This paper focuses on the characteristics of the marine clay, the basic design principles, layout and constructional issues of the CDM soil improvement, and numerical and numerical analyses to predict settlement and stability.

 article #2120; publication #1013 (DM-2015)