INFLUENCE OF SEEPAGE AND EXCESS PORE WATER PRESSURE IN GROUND ON SCOUR UNDER HIGH-SPEED FLOW

Abstract

Scour occured by floods lead to large topography variation and serious damage. Mechanism of scouring have been evaluated energetically conventionally by bottom shear stress, but in late years it has been argued that fluid power let stress in ground fluctuate and promote scouring. In this research, We performed movable bed experiment and theoretical consideration compared with interpretation in past to quantify influence of seepage flow and pore water pressure change in ground under high speed fluid on scour. As a result, character of seepage behavior while scouring was greatly different from theory solution in porous fixed bed which scouring is not occured. Particularly, it clarified that seepage flow to drain away ground outside and liquefaction let stability of soil greatly fluctuate. In addition, arrangement about seepage behavior in outer layer which varies according to grain size and thickness of permeable layer can improve prediction precision of scour analysis and showed that it connects to efficient and effective maintenance.