Abstract
Rising needs for environmental marine sand preservation forces us to substitute the supply condition of vertical drain from the plastic board drain (PBD).
Paper drain (PD), prior material in the market to PBD, was imported in Japan in 1963. It was allowed to have the function as a material for vertical drain. However, accumulated experiences proved PD materials have relay effect on consolidation velocity caused by deterioration of material. Therefore, since the paper the restriction as the drain material, development of PBD has been promoted to research. As the results of this investigation, composite type of PBD were produced.
In this paper, reviewing the history of development from PD to PBD, and summarizing the properties for material and remained item, directional research for PBD will be proposed.
