ABSTRACT
The Mansion House has been the official residence of the Lord Mayors of London for over 200 years. The Parliamentary Bill granting Royal Assent for the construction of the extension to the Docklands Light Railway included a clause that required the approval of the City Engineer before tunnelling beneath the Mansion House could commence. Originally, following the completion of the Waterloo and City Line pedestrian link, there were five other stages of tunnelling to be constructed within the theoretical or contractual zone of influence for the Mansion House. The application of the observational method guided the overall approach to manage and minimise the risk of damage to the Mansion House. In terms of the risk to the Mansion House and its response to induced settlement, it is instructive to compare the initial estimates with the results. The results demonstrated that for the Mansion House, the dominant component of the short-term settlement was accommodated in free-body rotation as predicted.
