Performance of Retaining Walls Backfilled with Blend of Sand and Building Derived Materials: A Laboratory Scale Study

Abstract

Disposal of the humungous quantity of generated construction and demolition debris is a serious problem in the present world. Although sands are considered as the most suitable backfill for retaining walls due to its high permeability, nowadays the scarcity of this natural material has raised serious environmental concerns. The present study aims at the sustainable and eco-friendly use of building derived materials (BDM) as a partial replacement of backfill material for earth retaining structures. An attempt is made to study the feasibility of utilizing BDM and its effect on at-rest, active and passive earth pressures on rotational mode of failure. Small scale laboratory model tests are conducted on a cantilever rigid retaining wall with different soil-BDM blends as backfill. The experimental results indicate that the earth pressures are not increased significantly by the inclusion of BDM to soil. For passive conditions, since the wall is made to rotate about its bottom, greater values of earth pressure is observed near the upper part of the wall and it decreases non-linearly with depth. Numerical simulations are conducted in line with the experiments to validate the observations. Since the numerical results suggest a good agreement with that of experimental results, it may be said that the finite element model provides enough support to validate the experimental outcomes. This model can be further used for research to evaluate the behavior of backfill soil with different BDM content. The present research is a step towards the sustainable and environment-friendly solution for recycling building derived waste material and has a significant practical impact on low cost construction of earth retaining structures.