Geosynthetic-reinforced soils are used in the design and construction of road and railway embankments over geotechnically challenging areas with high potential for void formation in order to limit the surface deflection over the void. Validation of the mechanisms by which deformation at the geosynthetic level is transferred to the surface is lacking in existing research and design methodology. Hence, centrifuge modelling of the behaviour of basal-reinforced granular fills over voids was conducted using a trapdoor model to simulate the void formation. A plane-strain model was used with a transparent window to allow the observations of soil deformations using Particle Image Velocimetry. Analysis of the soil displacement contours for tests conducted with different soil thicknesses allowed a description of the deformation behaviour to be defined in terms of the surface settlement profile, the shape of the zone of subsidence, and the expansion in the soil.