Relation between Liquefaction Damages and Grain Size Distribution of Liquefied Sand Caused by the 2011 off the Pacific Coast of Tohoku Earthquake in the Hinode Area of Itako City

Abstract

 The 2011 off the Pacific coast of Tohoku Earthquake caused significant liquefaction in the Kanto district. Many houses, roads, and lifelines were damaged due to liquefaction. Serious liquefaction damages occurred in the artificial filled land in the Hinode area of Itako City. We investigated house damage caused by liquefaction and conducted a borehole survey in the Hinode area. The results show that liquefaction occurred in the sand layer in man-made strata caused by a sand pomp system. It was revealed that the differences in house damages in the Hinode area was relate to the thickness and grain size distribution of the dredged sand layer in the man-made strata. The examination of grainsize analysis of the stratum with the possibility of liquefaction is a higher precision technique for evaluating the risk of liquefaction.