Sand boils along the Naruse River and the Yoshida River by the 2011 Tohoku-Region Pacific Coast Earthquake

摘要

Result of the investigation on geotechnical damage to river dikes along the Naruse River and the Yoshida River, Miyagi prefecture, from April 3 to 5 is reported focusing on soil liquefaction. Soil samples were collected from 14 sites where sand boils were observed. Liquefaction occurred at the natural ground such as old river bed or fill material to fill the old river channel. There found correlative relationships between the 50% diameter D _(50) and the distance D from the river mouth, and between the uniformity coefficient U and D ; D _(50) decreases and U increases as D becomes smaller.