A customised earth retaining system for deep excavation works

A world-class new cultural and arts centre of Singapore, Esplanade - Theatres by the Bay, is currently under construction. A customised 11-m free-standing earth retaining system consisting of an integrated diaphragm wall with buttress wall supports and improved jet-grouted soils has been adopted for the deep excavation works of the 11m-deep basement construction in soft Marine Clay. The lateral stability and rigidity of this unique excavation support system has been enhanced by the arching action of the retaining system, which is mobilised through basement slabs cast along the perimeter of the semi-circular frame of the basement. Ground deformations and wall movements were closely controlled and kept to a minimum with careful sequence of construction utilising this support system. This paper describes this excavation support system for the deep excavation works, as well as the observed field performance of the system, leading to the successful construction of the basement.