The response of surface structures to tunnel construction

Building deformation and the potential damage of buildings caused by tunnel construction in urban areas have become a major concern in the planning and construction process of any tunnelling project. The currently adopted design procedure is highly conservative, and can lead to costly projects. In 1997 Potts and Addenbrooke introduced design charts to consider the influence of the building's own stiffness, thus leading to more realistic predictions of tunnel-induced deformation. Their relative stiffness approach was based on a parametric study using plane-strain finite element (FE) analyses in which the building was modelled by weightless, elastic beams. This paper presents the results of both two- and three-dimensional parametric FE studies that extended their building model to include a wider variety of building features such as building weight, the nature of the soil–structure interface, and the building dimension in the direction of the tunnel axis. By incorporating these additional building features into their approach it is shown how the relative stiffness expressions can be modified to be dimensionless. New design charts that take account of the wide variety of building characteristics are presented for these new relative stiffness expressions.