THE INFLUENCE OF GEOFOAM CREEP ON THE PERFORMANCE OF A COMPRESSIBLE INCLUSION

Abstract A finite element analysis was conducted to evaluate the influence of geofoam creep on the performance of a compressible inclusion applied to a rigid retaining wall. The influence of geofoam creep was evaluated by modeling an instrumented case history incorporating limiting elastic moduli of the geofoam; that resulting from rapid liading tests, and that resulting from creep tests. It was found that the lateral stresses are highest under rapid loading conditions, and then decrease as the geofoam creeps. This stress reduction is coupled with a large strain increase. It was also found that the compressible inclusion may be most effective when it is applied over the full height of the wall. In the analyzed case history, the geofoam was placed only over the mid-section of the wall. The results of the finite element analysis reveal that this yields a classical arching stress state, with stress being transferred from the soil behind the compressing geofoam to the soil above and below. This resulted in a total lateral resultant force higher than that from the active stress state, that which is commonly assumed in design.