Centrifuge model studies on soil-nailed slopes subjected to seepage

Abstract

This paper evaluates the significance of nail reinforcement, influence of nail inclination and facing material type on the stability and deformation behaviour of soil-nailed slopes subjected to seepage. Centrifuge model tests were carried out at 30 gravities on model slope (5V:1H) with horizontal back slope having slope height of 7.2 m, soil nails spaced at 2.1 m x 2.1 m. All slope models were instrumented with pore water pressure and displacement transducers and markers were digitized to arrive at displacement vectors with rising ground water table within the slope during centrifuge tests. In addition, the center column of soil nails were instrumented at their mid-length to measure nail forces at the onset of seepage flow during the centrifuge test. An unreinforced slope was observed to fail once the seeping water reaches the toe of the slope. In comparison, soil-nailed slopes were found to stable at the onset of seepage. Soil-nailed slope with soil nails inclined at 10 was observed to perform better than a slope stabilized with soil nails inclined at 25. A soil-nailed slope with an aluminium facing was found to sustain large settlements as compared to fiber-blended plaster of Paris facing at the onset of seepage. Finally, an attempt has been made to compare results of stability analysis of centrifuge model slopes with and without soil-nails.