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液状化地盤に建つ杭頭半剛接合構法を採用した建物の遠心模型振動実験

表層の非液状化層に基礎根入れ部を有する試験体の実験結果とその分析

石崎 定幸^＊１・時松 孝次^＊２・長尾 俊昌^＊１

当社では，杭基礎の耐震性を向上させ，コスト縮減や掘削残土の低減が可能な杭頭半剛接合構法「F.T.Pile構法」を開発し，多くの物件に適用しています。地震時に液状化等の地盤変状が生じる敷地で本構法を採用する場合，その影響を考慮した設計を行う必要があります。本研究では，液状化地盤等の超軟弱地盤において本構法を採用した建物の地震時挙動を解明することを目的とし，液状化地盤-杭基礎-建物系の遠心模型実験を実施しました。前報の基礎が根入れされていない試験体の実験結果に続き，本報では，基礎根入れ部を有する試験体の実験結果から，根入れ部より生じる地震時土圧が本構法の杭被害軽減効果とその建物応答に与える影響について検討します。

＊１ 技術センター 建築技術研究所 建築構工法研究室
＊２ 東京工業大学

Dynamic Centrifuge Model Test of Pile-supported Building with Semi-rigid Pile Head Connections in Liquefiable Soil

Test Results and Analysis of Models with Embedded Footing in Non-liquefiable Surface Layer

Sadayuki ISHIZAKI^*1, Kohji TOKIMATSU^*2 and Toshiaki NAGAO^*1

We have been developing a semi-rigid pile head connection method called the F. T. Pile Method, which can economically improve earthquake resistance and reduce the volume of surplus soil. The method already has been adopted for many buildings. A safe design is necessary when the method is used in the very soft ground, such as liquefiable ground. The purpose of this study was to elucidate the seismic behavior of buildings with this method. To this end, we conducted dynamic centrifuge model tests of a building with this method in liquefiable ground. A previous paper described the test results of the models with non-embedded footings. In this paper, the test results of the models with embedded footings in a non-liquefiable surface layer were presented with the focus on the seismic earth pressure acting on the footing, the reduction in pile damage, and the response of the superstructure.