Effect of randomly distributed geofibers on the piping behaviour of embankments constructed with fly ash as a fill material

Abstract

Today, fly ash is being used as a structural fill material in highway and railway embankments, for ash pond bunds, levees, filling low-laying areas etc. Seepage induced failures in the form of piping can weaken and affect the performance of an embankment constructed with fly ash as a structural fill material. This paper presents a study to examine the effect of randomly distributed geofibers on the piping behaviour of fly ash. in this study, a number of experiments were carried out for determining the seepage velocity and piping resistance of fly ash, mixed randomly with flexible polyester fibers having various dosages and lengths. Seepage velocity of flow of water through fly ash is calculated for each case and compared with an unreinforced fly ash. It was observed that fibers reduced the seepage velocity, increased the piping resistance of fly ash and delays the attenuation of piping phenomena considerably. Finally the mechanism by which discrete and randomly distributed fibers restrain piping of fly ash is explained with the fly ash fiber interaction. (C) 2009