Senior Engineer, OTB
Engineering, London, UK;
Underpassing of Angel
Underground by London Ring Main Extension Tunnel
International Journal of Geoengineering Case Histories
Paper # IJGCH_2_2_2
ISSN # 1790-2045
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|Tunnels, tunnelling, underpassing, surveying, monitoring, TBM, EPB, ground movements
Copyright © 2004-2012 Elxis sa. All rights reserved.
This paper presents the predictions of movements, monitoring methods and measured movements of the Angel Station Upper Escalator and the Northern Line London Underground tunnels during tunnelling for the Thames Water Ring Main Extension Stoke Newington to New River Head (TWRM) tunnel. The earth pressure balance tunnel boring machine was driven from a launch shaft in Stoke Newington in an approximately southerly direction to a reception shaft in Islington, at depths of between 40 and 60 m. Along its route, the TWRM passed near to the Upper Escalator of Angel London Underground station, the longest escalator in western Europe, and soon after passed underneath two operational and one disused Northern Line tunnels. No discernible tunnel-induced movements of the escalator were observed. The measured movements of the tunnels were within the conservative expected value predictions of volume loss, but the trough widths were consistently narrower than expected.