JUBILEE LINE EXTENSION

Describes the construction of London Underground's Jubilee Line Extension. Gives details of the geology along the proposed route and the construction methods for the shafts and tunnels that will penetrate it. It will be the first time that NATM has been used in central London and problems, such as archaeological relics and contaminated land during penetration of the man-made ground mantle, are highlighted. Details of support to be used, mainly compensation grouting, are given. Many of the stations to be built will be underground multi-propped excavations affording opportunity for close monitoring of the effects of construction. A study into the response of structures due to excavation induced subsidence is being carried out throughout the project. -S.E.Long