Effect of confinement on creep behavior of EPS geofoam

Time-dependent deformation under sustained loading or creep is an important consideration in the long-term performance of expanded polystyrene (EPS) geofoam. The design of EPS geofoam fills is mainly based on limiting working stresses to produce tolerable deformations. Results from unconfined uniaxial creep tests have provided justification for such design criteria. With different types of applications involving submergence and higher surcharge loads, creep deformations under confining pressures have been occurring. A series of creep tests were performed on different densities of EPS geofoam with and without confining pressures. The results showed confining pressures can significantly affect the creep responses of EPS geofoam. Effects of confining pressures on creep deformations were more pronounced at lower densities.