Seismic Lateral Earth Pressure on the Retaining Wall with Sand-Tyre Mixture as a Backfill Material

During an earthquake, the lateral earth pressure behind the retaining walls increases drastically, which can damage the retaining walls. So, it is important to reduce the earth pressure by using lightweight materials as a backfill. Sand-tyre mixture can be a potential backfill material behind the retaining walls, but its application as a backfill material is less explored. In this study, numerical analyses are performed by utilizing finite element limit analysis to determine the horizontal earth pressure behind the retaining wall with sand-tyre mixture as the backfill material. The pseudo-static approach is used to simulate the effects of dynamic loading. In the present analysis, the value of horizontal seismic acceleration coefficient (kh) ranges from 0.1 to 0.3, and percentages of shredded tyre grains in the sand-tyre mixture are taken as 0, 10, 30 and 40%. The numerical analysis provides insights into the variation of lateral earth pressure along the height of the wall, as well as the factor of safety. The results indicate that as the percentage of tyre in the sand-tyre mixture increases from 10 to 40%, the maximum lateral earth pressure decreases by 8% to 31%, and the factor of safety increases upto 50%. Therefore, the sand-tyre mixture is a suitable option for use as backfill material behind retaining walls.