東北地方太平洋沖地震における津波越流に対する土構造物の安定性  [in Japanese] Stability of Earth Structures against Overflow of Tsunami during the 2011 off the Pacific Coast of Tohoku Earthquake  [in Japanese]

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Abstract

2011年東北地方太平洋沖地震では強い揺れとその後の津波で多くの構造物が被災した。海岸保全施設の多くが崩壊したが、河川堤防や盛土には地形や構造の違いにより被害程度に差が見られた。本論文は、土構造物の耐震性や耐津波性を検討するための基礎資料を得ることを目的に、津波被害を受けた岩手県中南部の2地点の土構造物の、現地調査や室内土質試験を行った。その結果、自然水位が高く貫入抵抗値の低い堤防では、表面被覆を有する場合でも津波来襲前に陥没崩壊する可能性が大きいことや、盛土表面を廃タイヤで被覆した擁壁では、健全性が保たれたことより、津波による外力への抵抗や洗掘防止効果が期待されることが明らかとなった。

Strong quake and the associated tsunami due to the 2011 off the Pacific coast of Tohoku Earthquake resulted in huge damage to many earth structures. A lot of coastal protection structures suffered heavy casualties due mainly to the erosion. However, the degree of damage to the river levees and embankments were different depending on the topography and the structural form. The main objective of this study is to collect basic information related to the seismic resistant and tsunami resistant characteristics of earth structures. To that end, site investigations and laboratory soil investigations on earth structures were performed at two locations of the central and southern part of Iwate prefecture. The investigation results show that subsidence related failure probably had taken place in the body of covered embankment with low penetration resistance and high water table. On the other hand, in the case of retaining wall made of tires, due to flexibility and ductility of the tires and the hoop tension that prevails within each individual tire prevented the wall from any damage due to erosion and the impact forces of tsunami.

Journal

  • Journal of Japan Association for Earthquake Engineering

    Journal of Japan Association for Earthquake Engineering 12(5), 5_89-5_101, 2012

    JAPAN ASSOCIATION FOR EARTHQUAKE ENGINEERING

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