FAILURE MECHANISM OF RIVER EMBANKMENT ON HIGHLY PERMEABLE FOUNDATION GROUND AND ITS ESTIMATION METHOD

Abstract

In the present paper, a series of two-dimensional seepage model test is carried out to investigate the mechanism of the seepage failure of river embankment due to highly permeable foundation ground. The experimental result indicates that the seepage failure of river embankment can be categorized to three patterns. In the low permeable foundation layer existing on the high permeable ground, the effective stress acting on the toe of slope is descending, as a result the slip failure of the slop that involve the foundation ground occurs. The slip failure is progressive and the magnitude of failure depends on the mechanical properties of embankment soils. The overflow due to the crown failure was observed in the model embankment made by relative loosen sand. The embankment soil in Futatsumori River which was broken by seepage failure was confirmed as loose sandy soil by performing the laboratory triaxial test. Finally, a new analysis method is proposed to evaluate the accurate stability of river embankment.