抄録
The 2011 Great East Japan earthquake caused many geotechnical damages such as liquefaction, failure of banks for housing lots and settlement of river dikes. Of them liquefaction occurred at many sites in Tohoku and Kanto districts. About 27,000 timber houses, a lot of buried sewage pipes and roads were damaged due to liquefaction. The very long duration of the main shock and an aftershock 29 minutes later probably induced the severe liquefaction and associated damage. Sidewalks and alleys buckled at several sites, probably due to a kind of sloshing of liquefied ground. 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. 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.
