Abstract

The development of infrastructure above areas where there is the potential for voids to occur, for example due to sinkholes or the collapse of underground mines, requires the use of mitigation measures to limit the impact of the voids. Similarly, the closure of landfill facilities and development above historical landfills also requires mitigation from the risk of voids due to collapse of waste and localised subsidence. In these applications, sheets of fabric-like material, called geosynthetics, are included at the base to span the potential void and support the above material. A series of centrifuge tests were conducted to investigate the deformation response when a void forms below a geosynthetic-reinforced soil. The aim of this research was to develop the limited understanding of the deformation mechanisms of soils and geosynthetics in response to the formation of a void, as this is crucial to ensure that the design of these systems is representative of the expected behaviour. In this seminar, a comparison of the reinforced and unreinforced soil behaviour will be presented based on visual observations from the tests conducted. The reinforced soil behaviour will be compared to the assumptions made in existing design methods, with indications as to where potential improvements the current design methods can be made. Particular attention will be given to the prediction of the soil arching effects, expansion in the soil above the void, the shape of the zone of subsidence, and characterisation of the soil surface settlement profile.