Jet-Grouting as Earth Retention System in the Canadian Pacific Northwest: Case History of a Challenging 16 Meter Deep Excavation

Jet-grouting is often used in British Columbia, Canada as an earth retention system for excavation support and, contemporarily, as water cut-off. This paper mention briefly few case histories, with particular emphasis on the application of jet-grouting technology, as a soil improvement technique, for the excavation support and the underpinning of the Georgia viaduct foundations, for the construction of a 32 story above grade tower with over five levels of below grade parking. Some iconic Vancouver Buildings, such as Olympic Village, built for the 2010 winter games, have been constructed with the use of jet-grouting, but, probably the most challenging is the Rogers Arena South Tower. The tower is located in False Creek, Vancouver, in proximity of Rogers Arena, home of the local NHL hockey team, the Vancouver Canucks, immediately North of Griffiths Way at Pacific Boulevard and South of the Georgia Street Viaduct. The presence of the existing viaduct results in extreme structural challenges that were overcome with the use of jet-grouting and micropiles. The paper will describe the jet-grouting soil improvement design and construction used for the underpinning of the viaduct piers and the temporary shoring, as well the instrumentation used for the monitoring of the viaduct piers and shoring.