A construction method that combines plastic board drains (PBD) to a construction method that promotes the self-weight consolidation phenomenon of reclaimed soil from dredged clay by dropping the water pressure of the soil base was put to practical use, showing tremendous results. A numerical simulation postulating this construction method was performed using a soil-water coupled finite deformation analysis in this study, demonstrating the accelerated effect of self-weight consolidation through this construction method. In addition, we studied the effect of dewatering and drain pitch, as well as the effect of clay soil thickness, demonstrating the characteristics possessed by this construction method. We also demonstrated that clay with ultra-high water content soil such as dredged clay can cover soil-water coupled finite deformation analysis through these analyses.
A large volume of dredged clay is discharged in order to obtain routes and berths for large vessels. In recent years, the development of manmade islands in combination with the disposal of this dredged clay has increased. Fostering consolidation speed and volume losses beyond what occurs from the soil's own weight is desired from the viewpoint of rapid use of these man-made islands and increases in the secondary quota of dredged clay. For these demands, paving sand is lined preliminarily in the revetment, as in the view shown in Figure 1, (a), then groundwater is pumped from the pumping well to drop the water pressure within the paving sand, thus the promotion of self-weight consolidation and volume loss of dredged clay are facilitated. In recent years, further promotion of self-weight consolidation in the Yumeshima region of Osaka has been targeted, and a construction method that combines the vertical drains as shown in Figure 1, (b) have been put into practical use, achieving tremendous results (Kiyama et al., 2000).
