波による液状化とパイプの浮上・露出対策  [in Japanese] DRUM CENTRIFUGE TESTS ON COUNTER MEASURES AGAINST WAVE- INDUCED LIQUEFACTION AND FLOATATION OF PIPELINE IN SAND BEDS  [in Japanese]

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Abstract

本研究では,波による液状化に伴う埋設パイプラインの浮上・露出対策の点から,砂地盤-パイプ―礫層(対策工)系の波浪実験を行い,地盤表層を礫層で置換する効果を詳しく調べている.実験は遠心力場70g場で行った.実験の結果,パイプ位置から60°の範囲の地表を礫層で置換すると,地盤の液状化抵抗が著しく増加すること,液状化発生後も広い範囲に礫層が残存し続けることで,液状化地盤の搖動を抑え,パイプの上昇や露出を効果的に抑制することを確かめた.一方,対策範囲を30°に留めると,地盤の液状化抵抗は無対策の場合から増加しないこと,液状化後は,地盤の激しい搖動によりパイプが著しく上昇すること,パイプの動きを対策工の端部で受けるため,パイプを抑えることができず,無対策の場合と同様の過程で地表に露出することが得られた.

 This paper discusses the experimental findings pertaining to the effects of gravel cover layer over a loose deposit of sand on wave-induced liquefaction and on behavior of buried pipeline in sand. The emphasis of the experiments was placed on investigating the interaction between the buried pipe, gravel cover and a liquefied sand bed. A series of wave tests using a drum centrifuge was performed under centrifugal accelerations 70 gravities. The experimental results showed that in the case of gravel layed in the range of 60 degrees avobe the pipe, liquefaction resistance increased significantly and the gravel layer prevented the liquefied sand to enhancing vibratation, where pipeline did not floated to the soil surface. It was found that the gravel layed in the range of only 30 degrees was insufficient measures for stability of buried pipe.

Journal

  • Journal of Japan Society of Civil Engineers, Ser. B2 (Coastal Engineering)

    Journal of Japan Society of Civil Engineers, Ser. B2 (Coastal Engineering) 74(2), I_1111-I_1116, 2018

    Japan Society of Civil Engineers

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