Building response to underground construction: the New City Court case history

摘要

New City Court in Southwark, southeast London, was recently affected by the construction of London Bridge underground station during the Jubilee Line Extension Project. It consists of two separate but linked structures: a Victorian terrace and a piled 4-storey reinforced concrete framed office block. Protective measures, comprising compensation grouting within the underlying London Clay, were implemented from a temporary grouting adit adjacent to the Victorian terrace, to control the movements of the buildings during the underground construction works. The responses of the two structures, as well as the construction joint at their junction, to the various construction activities was monitored by a variety of methods, including precision levelling and crack measurement. The results of this monitoring together with contour plots of grout injection intensity are presented in this paper as well as a discussion of the observed responses of the structures. It is demonstrated that the compensation grouting protective measures controlled ground settlements such that the maximum building movements recorded were less than 35 mm.