Abstract: This paper presents a case history of deep excavation of Kaisa Square, of which the main structure is very close a subway station with restrictive deformation requirements. The excavation supporting system design considered the safety and the cost effectiveness and combined the supporting structure with the construction of main structure. This approach resolved the limited construction space due to the constraint of the adjacent subway station and the consequent construction safety concerns. The construction monitoring data indicated that the application of this method is successful. The feasibility as well as the characteristics of using the combination approach with the conventional deep excavation sequences such as central part by bottomup method and peripheral part by topbottom method are also discussed in this paper.

Key words: Composite Method of Excavation Support, Main Building Structure, Inner Support Bracing Structure