This paper presents a simulation of the sand-geosynthetic interaction based on pullout tests carried out in the Geosynthetics Laboratory of the Sao Carlos School of Engineering of the University of Sao Paulo. With the experimental results, it was determined the pullout strength of a polyester geogrid installed within a poorly graded sand, under confining stresses of 25, 40, 55 and 75 kPa. The simulation was performed in SIGMA/W of GeoStudio and the chosen parameters were selected carefully for representing the real behavior of the interface. In addition, the simulation of the geogrid geometry in this program is only possible in one direction, thus being necessary for an adaptation to consider the real effect of the transversal and the longitudinal elements in its stiffness. Finally, this work showed a good relationship between experimental and numerical results, validating the performed simulation and evidencing that numerical modeling can bring a lot of advantages.