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Study on volume reduction method for dredged soil by electro-osmosis -An investigation into applicability of electro-osmosis in clays-

Publication year

Port and Airport Research Institute　Technical Note　1404　2022.06

Author(s)

Yuri SUGIYAMA, Daiki TAKANO, Yoshiyuki MORIKAWA

Department
/Divison

Geotechnical Engineering Field Soil Mechanics and Geo-Environment Group

Executive Summary

A large amount of soil is dredged every year due to dredging for the purposes of maintaining sea routes and harbors and deepening the front of seawall due to the increase in size of ships. Almost of dredged soil is disposed by ocean dumping or landfill so far. However, it has become an urgent issue which is maintaining disposal site because the capacity is getting tight. One of the volume reduction methods to solve this problem is consolidation dehydration. Currently, it thought that the vacuum consolidation is the most effective volume reduction method of dredged material which have high water content and low bearing capacity. However, the counter-measure by vacuum consolidation is not enough to reduce the volume of dredged soil because of the constant dredging. For that reason, the other volume reduction methods, volume compression by stirring the clay ground and sedimentation promotion technology by aggregation of clay particles, were proposed. In this study, applicability of these volume reduction methods was examined. Moreover, applicability of new volume reduction method by electro-osmotic dehydration was also examined. The electro-osmotic dehydration is the application of electric current to the soil through electrodes that are inserted into the saturated soil where water can be drawn from the anode to the cathode via electro-osmosis.
At first, we organized issues of which was already proposed volume reduction methods by using analysis simulation and performing model experiment. Next, the electro-osmotic consolidation test was conducted to consider the effectiveness of electro-osmotic dehydration. As a results, it was revealed that the electro-osmotic dehydration method was very effective of volume reduction of dredged soil.

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