Earth Pressure Distribution on a Rigid Box Covered with U-Shaped Geofoam Wrap

Earth loads acting on buried structures are known to be influenced by the characteristics of the soil, and the stiffness and geometry of the structure. To reduce earth pressure acting on buried structures, the induced trench installation technique has been recommended and applied in practice for several decades. It involves the installation of a soft zone immediately above the buried structure to mobilize shear strength in the backfill material. In this study an experimental investigation is conducted to measure the changes in contact pressure on the walls of a rigid structure buried in granular backfill with a U-shaped geofoam wrap. The results are compared with the conventional induced trench method as well as the positive projection installation with no geofoam. Contact pressures on the walls of the structure are measured using the tactile sensing technology. The experimental results are used to validate a finite element model that has been developed to analyze this soil–geosynthetic–structure interaction problem. The numerical model is then used to study the soil arching and the stresses developing in the backfill material for three different EPS densities. In addition, the role of geofoam density and the maximum fill height that can be carried safely without exceeding the design strain levels are examined. Conclusions are made regarding the effectiveness of this type of EPS inclusion on the earth pressure distribution around the buried structure.