Execution for the volume reduction of dredged soil using the vacuum consolidation method with horizontal pre-fabricated drains

摘要

Recently, a shortage of soil disposal area has been serious in Japan, and there has been a demand to dispose the dredged soil as much as possible in the disposal area with limited capacity. To meet this demand, the vacuum consolidation method with horizontal pre-fabricated drains has been applied to the soft ground formed by dumping of dredged soil. Horizontal drains of 100cm wide, 10mm thick and 117-171m long were installed at the horizontal interval of 0.8m on the bottom surface and a middle section of the disposal area. Then, soft soil was improved by the vacuum pressure of over 75-80kN/m~(2). The volume of dredged soil converted in the original sedimentation condition was 1.1 times as much as the capacity of the disposal area, though all of the dredged soil was successfully accepted in the disposal area because of bulk reduction of the soil by the vacuum consolidation method.