Study on Interface Interaction between Uniaxial Geogrid Reinforcement and Soil Based on Tensile and Pull-Out Tests

The interaction between reinforcement and soil is a key problem in the application of geosynthetics as reinforcement in geotechnical engineering. In this study, tensile and pull-out tests on a uniaxial geogrid were carried out using self-designed tensile and pull-out test equipment. The tensile test evaluated the tensile load-strain characteristics of a geogrid. Under the condition of lateral confinement, the tensile force and secant tensile stiffness of the geogrid increased with an increase in the normal stress when the strain was constant, and the secant tensile stiffness decreased with a decrease in the tensile rate. The stiffness coefficient was used to quantitatively describe the change in the stiffness of the reinforcement. Using the pull-out test, the variation laws of the pull-out force of the geogrid under different normal stresses and different longitudinal rib percentages were obtained. When the geogrid was broken, the pull-out force of the same type of geogrid was not significantly different under different normal stresses. With an increase in the longitudinal rib percentage, the pull-out force of the geogrid under the same normal stress gradually increased, and the apparent friction coefficient was obtained by analysis. The results of the apparent friction coefficient obtained by the analytical method in accordance with French specifications (NF P94-270-2020) are relatively safe compared to the experimental values.