The Plastic Board Drain (PBD) method for self-weight consolidation has been proposed by authors as one soil improvement method in reclamation works for use with high water content dredged soils. This method is a vertical drain method for accelerating self-weight consolidation using a PBD and floating driving machine to consolidate such very soft ground in a short period. This paper describes laboratory tests of the combined application of the dewatering method and PBD method. This method also makes it possible to increase the capacity of soil disposal sites (extending the life of waste disposal sites), and it is expected to help resolve the widespread and increasingly serious problem of the lack of waste disposal sites. Furthermore, without the use of loading, a coastal landfill site filled by pumping in sludge using a pump type dredging ship.
(figure 1 shown in paper)
In recent years, for maintenance of navigational channels or purification of the environment, it is often planned to dredge clayey deposits on the surface of the seabed, and utilize the dredged spoil as landfill and manmade islands. Typically, the dredged spoil is temporarily stored in a nearby sedimentation pond and then very soft ground is formed. Since an artificial ground filled with the spoil has very high water content such as 200 to 300%, it is necessary to consolidate it properly for the utilization in landfill and manmade islands. Kamon et.al.(1991), Shinsha et.al.(1991) and Yoshikuni et.al.(1994,1995) have studied the vertical drain method using plastic board and horizontal drain method as one soil improvement method for reclamation works for dredged clay. Therefore, the authors have developed the vertical drain method for accelerating self-weight consolidation using plastic board drains as a method of consolidating such very soft ground in a short period.
