Recently, our ocean development paradigm is changing so that the development focus hasbeen moved from the port facility developments to creating useful marine space. This paradigm accords well with the current green technology and helps the growth of service industries and the development can become a land mark of country. Accordingly, the concept of creating marine waste landfill by the development of resource recycling technology has been introduced for eco-friendly space as an artificial island in future.Therefore, this paper introduces the reactive vertical drainage method that is to pursue the purification of pollutants as well as stabilization of newly deposited soils in marine environments. To place the reactive vertical drainage piles for more effective feasibility and constructability, placements of drainage mid layer are considered. The effective spacing of mid-layer drainage suitable for purifying dredged soil were evaluated with finite element analysis in terms of the duration of primary consolidation and settlements.