排水を利用した小規模構造物、外構用簡易液状化対策の遠心模型実験
地表付近に排水性の高い礫層を設けることで、小規模構造物や外構の液状化被害を大幅に低減する対策の効果を遠心模型実験で確認した。礫を用いて基礎底近傍や表層付近を厚さ30cm以上置換することにより、地盤が液状化に至っても構造物の傾斜を大幅に小さくでき、噴砂も抑止できることを確認した。排水性のないセメント改良で行った実験では、液状化が継続している間、構造物の傾斜が増加し続け、被害抑止の効果は小さかった。液状化層からの排水性を確保することが、液状化被害低減に有効であることを確認した。
Centrifugal model tests on simplified improvement method for reducing liquefaction damage of small structures and outdoor facilities, using by drainage
The new improvement method that can reduce the liquefaction damage of the small structures and the outdoor facilities by making the high permeable gravel layer near the ground surface is proposed. The proposed method makes the gravel layer of more than 30cm thickness beneath the structure, and drainage to ground surface is provided. The effect of the proposed method is confirmed by centrifugal model tests. The proposed methods do not have the effect to prevent liquefaction, but the damage of structure can be remarkably reduced. In the cases of the cement treated soil with very low permeability instead of gravel, the inclination of the structures continued increasing during liquefaction. It is effective for reducing liquefaction damage by drainage from the liquefaction layer.