EPS geofoam : an engineering material for geotechnical applications

Expanded Polystyrene (EPS) geofoam is an extremely lightweight, highly compressible cellular polymeric material which is widely used as a thermal insulation in the housing industry. Its possible use in geotechnical applications has received much less attention especially in Australia. Due to its extreme lightweight and high strength/stiffness to weight ratio, EPS geofoam is an excellent material for building road embankments on very soft soils and in slope stabilisation, while its high compressibility makes it a material of choice as a compressible inclusion. The last application, in particular, has attracted much attention in recent years as engineers attempt to exploit the concept of reducing earth pressures acting on rigid structures by introducing a buffer layer of compressible material between the two. EPS geofoam is a viable cost-effective solution for many geotechnical problems despite its lack of application in Australia. Thus, the purpose of this paper is to inform engineers of some of the benefits/advantages of EPS geofoam and to highlight key aspects of its behaviour based on triaxal and creep compression tests. In numerical analysis, a yield function for an elastoplastic model of EPS geofoam is suggested.