Numerical Studies on the Performance of Geosynthetic Reinforced Soil Walls Filled with Marginal Soil

This paper is to investigate the performance of geosynthetic reinforced soil (earth) wall, popularly known as GRS walls, backfilled with the marginal soil. Over the years, granular soil has been predominantly used as the backfill material owing to its high strength, good drainage characteristics and easily compactable. However, due to lack of availability, transportation issues, granular soil is not abundant in many of highway project site. Marginal soil can be defined as the percentage fines greater than fifteen percent or having plasticity index more than 6. Poor drainage and low shear strength and development of pore water pressure due to presence of fines are major design constraints in using marginal soil as the GRS wall backfill. The present research compares the performance of marginal backfill with clean granular soil using numerical analysis. For this purpose, a two-dimensional finite element model has been developed to study the performance of GRS wall under dry-state conditions. Further parametric study has been carried out to study the effect of surcharge, reinforcement length, spacing, wall facings, and wall height. The wall displacement has been considered as the major performance criteria. Based on the analyses, it has been found that marginal soil can be used as backfill, provided higher strength of geogrid has been used. A real-life case study has been analyzed for different heights of GRS wall sections to understand the deformation behavior of the wall by using marginal fills.