M.R Abdi - Associate Professor, Faculty of Civil Engineering, KNT University, Tehran, Iran
A.R Zandieh - PhD Student, Faculty of Civil Engineering, KNT University, Tehran, Iran

Reinforcements like bars, strips, textiles and grids are used for the reinforcement of soil walls, but the useof grids type of reinforcements is still under consideration and there is still a need of study the probableuse of grids reinforcement in reinforced soil retaining walls. Pullout test is commonly used to predictactual field pullout behavior of reinforcements. In this paper, pullout test modeled with geogridreinforcements embedded sand, clay and clay with thin layers of sand, under five different normalpressures of 5,25,50,75 kPa and 100 kPa. Finite element method (Plaxis V8) is used to compare thepullout behavior results. Normal pressures modeled and an optimum sand layer thickness wasdetermined. Effect of sand layers combined with the geogrid reinforcement increased with increasing innormal pressures. The improvement was more pronounced at higher normal pressures. Test resultsindicate that provision of thin layers of sand on both sides of the geogrid is very effective in improving thepullout strength

Numerical Modeling (Plaxis V8), Geogrid, Clay, Sand, Pullout test