Subsurface settlement profiles above shallow and deep model tunnels at large ground loss

A major concern in the construction of any tunnel in urban areas is the ground movements that inevitably take place. Geotechnical engineers are responsible for assessing these ground movements in association with tunnel design and have to demonstrate that neighbouring structures will not be subject to excessive differential settlements. The study presented in this paper focuses on the subsurface settlement profiles above shallow and deep tunnels in granular material simulated by aluminium rods. In order to provide theoretical deformation patterns during two-dimensional volume loss, CRISP is used for the finite element analysis. Comparison is then made with idealised laboratory tunnel model tests using close range photogrammetry to measure displacement pattern in a multi sized rod mixture. FEA based on the test results is shown to be in good agreement with the physical model data.