Improved understanding of geogrid response to pullout loading: insights from three-dimensional finite-element analysis

Abstract

Soil reinforcement has rapidly become one of the most common soil improvement techniques used in geotechnical engineering. Understanding the behavior of a geogrid under pullout loading is essential for the analysis and design of reinforced soil systems. The overall behavior of reinforced soils is generally dependent on the properties of the geogrid material, the backfill soil, and the interface condition. Modeling the three-dimensional aspects of soil–geogrid interaction under pullout loading condition is numerically challenging and requires special consideration of the different modes of resistance that contribute to the pullout capacity of the geogrid reinforcement. This study describes the results of a three-dimensional finite-element analysis that has been developed to investigate the behavior of a biaxial geogrid embedded in granular backfill material and subjected to pullout loading. The modeling approach considers the noncontinuous nature of the geogrid geometry and the elastoplastic response of the geogrid material. Model validation is performed by simulating laboratory-size pullout test and comparing the experimental data with the analytical as well as numerically calculated results. The detailed behavior of the geogrid and the surrounding backfill is investigated using the proposed numerical approach. Conclusions are made to highlight the suitability of this technique for analyzing similar soil–structure interaction problems.