Stress-strain behaviour of reinforced dredged sediment and expanded polystyrenes mixture under cyclic loading

Abstract

Reinforced soil and Expanded Polystyrenes (EPS) mixture (RSEM) is a geomaterial which has many merits, such as light weight, wide strength range, easy for construction, and economic feasibility. It has been widely applied to improve soft ground, solve bridge head jump, fill cavity in pipeline and widen highway. Reutilizing dredged sediment to produce RSEM as earthfill can not only consume a large amount of waste sediment but also significantly reduce the construction cost. Therefore, there is an urgent need understand the basic stress-strain characteristics of reinforced dredged sediment-EPS mixture (RDSEM). A series of cyclic triaxial tests were then carried out on the RDSEM and control clay. The effects of cement content, EPS beads content and confining pressure on the cyclic stress-strain behaviour of RDSEM were analyzed. It is found that the three stages of dynamic stress-strain relationship of ordinary soil, vibration compaction stage, vibration shear stage and vibration failure stage are also applicative for RDSEM. The cyclic stress-strain curves of RDSEM are lower than that of control clay in the vibration compaction stage because of its high moisture content. The slopes of backbone curves of RDSEMs in the vibration shear stage are larger than that of control clay, indicating that the existence of EPS beads provides plastic resistance. With the increase of cement content, the cyclic stress-strain relationship tends to be steeper. Increasing cement content and confining pressure could improve the cyclic strength and cyclic stiffness of RDSEM.