Consideration of Rate Effect on Pullout Behavior for Geogrid Reinforced Soil Structures under Dynamic Loading

This paper presents an experimental study to investigate the effect of loading rate on the pullout behavior of high density polyethylene (HDPE) geogrids confined in compacted dry sand. A series of pullout tests were performed under different displacement rates, initial sand relative densities, and vertical stresses using a pullout device that incorporates standard elements such as roller grips, a motor for displacement-control pullout, and instrumentation for pullout force and displacement measurement. For comparison, a series of in-isolation tensile tests on single-rib geogrid specimens were also performed under different loading rates. Test results indicate that the in-isolation tensile behavior of HDPE geogrid is significantly affected by loading rate, while the pullout behavior of geogrids confined in soil shows negligible rate effects for different initial relative densities and vertical stresses considered.