Performance of 2V:1H Slopes with and without Soil-Nails Subjected to Seepage: Centrifuge Study

This paper presents the results of centrifuge model tests on the behavior of a slope subjected to seepage with and without soil-nails. Centrifuge model tests were carried out at 30 gravities on model slopes with horizontal back slope having an inclination of 2V:1H and slope height of 7.2 m using a 4.5 m radius beam centrifuge facility available at IIT Bombay. Nail inclination of 25o with horizontal was adopted for reinforcing slope along with polyester fiber-blended plaster of Paris facing. An unreinforced slope was observed to fail once the seeping water reaches the toe of the slope after 5 days of seepage. In comparison, the 2V:1H slope strengthened with a soil-nail layout of 2.1 m x 2.1 m and inclined at 25o was found to significantly improve its stability and deformation behavior at the onset of seepage.The observations also indicate that the use of plaster of Paris strengthened with polyester fibers facing is viable option for modeling facing in centrifuge model tests. Further, the results on stability analysis of soil-nailed slopes with different layouts indicate that the horizontal spacing of soil-nails greatly influences the stability than vertical spacing and slope facing plays a significant role in improving the stability of soilnailed slopes. Finally, an attempt has been made to compare results of stability analysis of centrifuge model slopes with and without soil-nails.