Numerical modeling of the use of geosynthetics in improving the behavior of subgrade soil

In this research, numerical simulation using the finite element method and PLAXIS numerical software (version 8.2) were used. Also, the calculation point of the road settlement, which is the criterion for comparing different models, is selected in the loading center on the road, which is considered as the representative of the road settlement in the output results of the vertical displacement. The results of the numerical investigation of the effect of the tensile strength of geosynthetics on the road settlement show that this parameter did not have a significant effect on the road settlement. Also, from the numerical modeling of the effect of the length of geosynthetics on the road body, it is determined that the settlement of the road in modeling with geogrid is the same size as the width of the road (which is equal to 7 meters in this model) equal to 3.65 mm and with geogrid 9 meters wide. It is equal to 3.5 mm. The results showed that if the amount of friction between the geosynthetic element and the soil is considered equal to the internal friction angle of the soil, the settlement of the road at the loading center of the model has decreased by 12%. Finally, the investigation of the effect of geosynthetic element placement on the road settlement shows that by moving the geosynthetic layer from the sub-base-substrate boundary to the top-base boundary, the road settlement decreased by 0.9 mm.