Traditionally liquefaction issues of river levees concerned the foundation soil under a levee
body. However, one of the recent problems is the liquefaction inside a levee. This remark
may sound strange because a levee is located above the ground surface and, therefore, above
the ground water table and also because a levee is considered to be compacted. Photo 5
illustrates a typical damage caused by liquefaction inside a levee. Noteworthy is the profound
distortion of the levee slope that is in good contrast with the intact shape of the unliquefied
ground surface. The mechanism of the levee’s internal liquefaction is discussed as what
follows;