ABSTRACT
ABSTRACT: This paper describes damages to river dikes during the 1993 Kushiro-oki Earthquake and the 2003 Tokachi-oki Earthquake. During the Kushiro-oki Earthquake in 1993, it was found that dike failures were induced by liquefaction which occurred within a submerged part of fill. This condition was brought by consolidation of a peat layer beneath dikes. Dike failure in this case showed the importance of drainage to prevent the infiltrated rainwater from accumulating within a dike body. During the 2003 Tokachi-oki Earthquake an unusual type of damage was detected. Vertical cracks were found within a dike section at a location where no apparent abnormality was visible at the surface. Evidence suggests that the cracks were caused by expansion of the bottom width of the dike.
