抄録
The 2011 Great East Japan earthquake caused severe liquefaction in Tohoku and Kanto districts. About 27,000 timber houses, a lot of buried sewage pipes and roads were damaged due to liquefaction. In Tokyo Bay area, liquefaction occurred in a wide area from Shinkiba in Tokyo through Urayasu, Ichikawa and Narashino cities to Chiba City Dredged and filled soils must have been liquefied by the earthquake. The very long duration of the main shock and an aftershock 29 minutes later probably induced the severe liquefaction Sidewalks and alleys buckled at several sites, probably due to a kind of sloshing of liquefied ground Moreover, much sand boiled from the ground and the ground subsided significantly because the liquefied soils were very fine Many houses settled notably and tilted. Sewage pipes meandered or were broken, their joints were extruded from the ground, and many manholes were sheared horizontally. This remarkable damage might have occurred due to the sloshing of liquefied ground. In reclaimed land along Pacific Ocean, many facilities were damaged as well as Tokyo Bay area due to liquefaction. In an industry facility, oil fences tilted and machinery rooms sunk.
