Pullout Tests and Analysis of Reinforced Soil Interfaces at High, Medium and Low Pullout Rates

Landslide and retaining wall collapse damage will cause rapid sliding between geogrids and soil, and the interaction of reinforced soil interfaces is complicated. It helps to deepen the understanding for mechanical characteristics of reinforced soil interfaces by studying the force and deformation characteristics of reinforced materials at interfaces at different pollout rates. Thus, the pullout tests with nine pullout rates and 3 normal loads were conducted, which were expected to explore the effect laws of pullout rates and normal loads on mechanical characteristics of reinforced soil interfaces. The results showed that the increase degrees of peak pullout force gradually slowed down with the increase in pullout rates. The interfacial cohesion was positively correlated with pullout rates, and it had grown by a maximum of 278%; the interfacial friction angle was negative correlated with pullout rates, and it had decreased by a maximun of 19.1%. The strain of the geogrids was more seriously influenced by pullout rates at low speeds and increased with the increase in pullout rates; when the pullout rate exceeded 5 mm/min, the strain variance of geogrids decreased and the pullout stiffness of geogrids increased. The interfacial shear dilation increased with the increase in pullout rates, and decreased with the increase in normal loads. The interfacial shear dilation at high speed was about 1.56 times of that at low speed and about 1.13 times of that at medium speed.