Ground collapse: effect of building position on tunnelling-induced soil movements

The mechanisms of tunnelling-induced ground movements are important for risk assessments of tunnelling beneath masonry buildings with shallow foundations, including ground collapse disasters. This paper presents results from five geotechnical centrifuge tests to investigate tunnelling-induced ground movements under the influence of the relative position between the tunnel and a masonry building in plain strain conditions. The tunnel eccentricity-to-building length ratio (e/L) ranges from 0 (tunnel directly below building centre) to 1/2 (tunnel directly below building edge). An advanced coupled centrifuge-numerical modelling (CCNM) method was employed, where the soil, tunnel, and strip foundation are represented in the experimental domain, and the masonry building is modelled in a numerical simulation running in parallel, with key vertical displacements/loads transferred between the domains at the shared boundary (i.e. beneath the building and above the strip foundation). The CCNM approach highlights the significance of building load redistribution on the ground response during centrifuge testing. Results demonstrate that surface and subsurface ground movements in tunnelling scenarios are altered by nearby building positions. It presents the changes in soil vertical and horizontal displacements, key parameters of settlement troughs, soil volume loss, and engineering shear and volumetric strains of the soil. This study provides insights into the mechanisms of tunnelling-induced ground movements under the influence of nearby buildings and serves as an important reference for risk assessments of the construction of new tunnels as well as for numerical and theoretical studies.