Pullout Behaviour of Reinforced Earth Walls with Cohesive Soil: A Review

Abstract: Reinforced earth walls constructed with cohesive backfills pose significant challenges due to the low shear strength and poor drainage properties of fine grained soils. This study reviews existing literature on the pullout behavior of geogrid reinforcements in cohesive soils, with a focus on applicability to field conditions in Dakor, Gujarat. Key research findings from laboratory and field studies including the effects of interface friction, drainage enhanced geogrids, lime treated soils, and geosynthetic type are analysed and compared. The case study of a geotechnical investigation conducted at the Dakor site reveals a subsurface profile dominated by silty clays of intermediate plasticity, with shear strength parameters and Atterberg limits comparable to those used in prior research. The review highlights that while cohesive backfills inherently limit interface friction (typically φ = 15-18°), the use of sand layers, high transmissivity geogrids, and compaction improvements can significantly enhance pullout resistance. The study concludes by recommending site specific pullout tests and interface characterization to validate design assumptions and optimize wall stability in the local context. These findings provide a basis for safer, more cost effective design of reinforced earth walls in regions with similar soil conditions.

Keywords: Pullout behavior, reinforced earth walls, cohesive soil, geogrid, interface friction, Dakor, geotechnical investigation, drainage geogrid, lime treated soil.