Post-cyclic Pullout Response of Geogrid in Compacted Sand and Clayey Sand with Emphasis on Pre-cyclic Load Effect

Soil-geosynthetic interface behavior under cyclic loading will differ from that under static loading. To this end, a series of static and multistep tests were carried out using a large-scale pullout apparatus to investigate the effect of static and cyclic loads on the pullout behavior of a PET geogrid buried in compacted, uniform clean sand and clayey sand. In static pullout tests, the influence of the normal pressure was studied on geogrids buried in both types of soil and the normal pressure and pre-cyclic load level were examined in the multistep tests. The results of static tests revealed that the pullout behavior of geogrids was substantially affected by the level of normal pressure and the soil type. The displacement through the geogrid in both clean sand and clayey sand increased with increases in the pullout load at the onset of cyclic loading and the normal pressure. The post-cyclic pullout resistance was not significantly affected by the pre-cyclic load values. Moreover, under similar conditions, the displacement generated at the front of the geogrid buried in clayey sand was lower than that recorded for clean sand.