Limiting the damage to historic buildings due to tunnelling: experience at the Mansion House, London

Abstract

This paper describes the effects of previous tunnelling on the fabric and foundations of The Mansion House, an 18th century Grade I Listed Building in the City of London. In mid-1988, a tunnel was constructed approximately 15m below the building. This tunnel was to be the first of a number of additional tunnels to be built near the Mansion House, associated with the extension of the Docklands Light Railway to Bank Station. The effect of the first tunnel is described together with predicted and measured movements. The predicted effects of the other tunnels are also outlined. Measures proposed for protecting the Mansion House are described, along with the system which was adopted. A sophisticated system to monitor building and ground movements during and after the construction of the tunnels has been installed. This paper is based on another by Frischmann et al (1994).