INFLUENCE OF SEEPAGE FLOW HISTORIES ON DETERIORATION WITHIN EMBENKMENTS

Embankment structures are important to protect against flooding damage. Suffusion, in which fine particles within the soil are transported and washed away following the seepage flow, intensifies the instability of embankment structures. Therefore, it is possible that some embankment structures that repeatedly experienced flooding and rainfall penetration have been deteriorated. However, there is little research investigating the relation between seepage flow histories and deterioration within the embankments. In this study, small-scale modeling tests duplicating a river levee were conducted under different seepage flow histories: (i) short term-critical ground water level, (ii) continuous-high ground water level and (iii) repeatedhigh ground water level. The work in this paper investigates changes in “drainage flow rate”, “height of ground water level” and “particle size distribution” during the seepage tests, and evaluates the effects of seepage flow histories on them. Soils gradually showed lower permeability under the first seepage experience in each cases. In the case of relatively longer flooding duration, the drainage flow rate is gradually increased. Fine particles were eroded, regardless of the seepage flow histories; “the number of fluctuations” and “height” of ground water level could particularly be a trigger of suffusion.