<p>The sandwiched geogrid reinforced soil (SGRS), which adopt clay reinforced with geogrid encapsulated in thin layers of sand, has wide application prospects owing to the extensive availability of clay. In this study, the pullout behavior of the SGRS was simulated using DEM software PFC2D. The microscopic properties, including particle displacement, porosity, and major and minor principal stresses, were analyzed. The influence of the sand layer thickness on the pullout performance of the SGRS was also investigated. The inclusion of a sand layer significantly increased the number of mobilized particles and the magnitude of displacement during the pullout test, ultimately leading to the formation of two closed displacement loops. The bond breakage between clay particles resulted in an "X"-shaped fracture pattern. The contour maps of the maximum principal stress showed bracket-shaped isolines (" &lt; " and " &gt; ") symmetric about the reinforcement. Both fractures and higher maximum principal stresses were more concentrated and intense near the wall containing the pullout outlet. Shear dilation occurred in the soil adjacent to the reinforcement, leading to an increase in porosity. Furthermore, compared to the pronounced effect of introducing a sand layer, further increasing its thickness yielded only marginal additional improvements in clay particle mobilization, near-reinforcement porosity, and zones of increased major principal stress.</p>