Accelerated consolidation of dredged marine soils with incorporation of granular wastes as drainage layers

Dredging activities for nearshore marine facilities maintenance and development have long been known to bring adverse effects to the environment potentially. It is particularly so because of the disposal of unwanted dredged materials (DMS) at sea, which disrupts the balance of the marine ecosystem. On the other hand, industrial by-products and construction wastes such as palm oil clinker (POC) and recycled pavement materials (RPM) respectively have posed dangerous menace too on land with poorly managed dispossessing these waste materials as substitutes for virgin materials in the construction industry significantly loosened their negative impact on the surrounding. This paper presents the experimental program of a series of oedometer tests simulating the reuse of DMS as reclaimed backfills, incorporated with granular drainage layers of POC and RPM to expedite the consolidation process. The dissipation of excess pore water from the soil and resulting settlement was observed at a shorter time in the sample with the POC drainage layer than the one with RPM. The subsequent reduction of compressibility and improved stiffness of the DMS enabled it to sustain a more significant load via the pre-loading approach, where subsequent subsidence of the reclaimed ground would be predictable and limited. The findings give a promising notion of reusing the granular waste materials as an incorporated drainage layer for DMS reuse in reclamation works, simultaneously accelerating the consolidation process and giving useful second lives to the otherwise waste materials, with many potential applications in other areas of civil engineering too.