Abstract
Installation of steel sheet piles at the toe of a levee has been adopted as a countermeasure against liquefaction of the levee foundation in earthquake. Recently, installation of the steel sheet piles at the shoulders of the levee with tying the sheet pile heads by rods is proposed to secure the function of the levee both in earthquake and in overtopping. Since installation of the sheet piles alters the seepage flow in the foundation ground, use of permeable steel sheet piles is also proposed. On the permeable sheet pile, there are holes sufficient to secure the water flow in the ground so that the existence of the sheet pile does not interrupt the seepage flow. However, near the holes, onset and development of internal erosion might occur by the concentrated seepage flow due to the large hydraulic gradient around the holes. In this study, development of internal erosion near the holes on the permeable steel sheet pile is simulated by combining seepage flow analysis and internal erosion analysis. Comparison with physical model test reveals that the experimental result can be captured by the numerical analysis as a whole. However, the clogging of fines in the experiment cannot be modelled, as fines once detached from the soil skeleton cannot be redeposited again with the internal erosion model used in this analysis.
