Dynamic behavior and characteristics of geogrid-reinforced sand under cyclic loading

Abstract

This paper evaluated the benefits of geogrid-reinforced sand samples and investigated the effect of different factors contributing to the dynamic behavior, which included the geogrid type, arrangement of reinforcement, confining pressure and dynamic stress amplitude. Four geogrids of different aperture geometries (two biaxial geogrids and two triaxial geogrids) produced by 3D printing technology were used. The research was experimentally carried out by conducting dynamic triaxial tests to investigate the axial cumulative strain, dynamic elastic modulus and damping ratio of the samples. The test results demonstrated the potential benefit of installing geogrids in subgrade soils. Less axial cumulative strain, damping ratio and larger dynamic elastic modulus were measured under cyclic loading for geogrid-reinforced samples compared to those unreinforced samples. The geogrid type and reinforcement arrangement had noticeable impacts on the samples’ dynamic performance. Of the four model geogrids tested, the triaxial geogrid with triangle aperture performed consistently better than the other three. Under large confining pressures and dynamic stress amplitudes, there was no appreciable improvement in the dynamic performance of the samples reinforced with the two triaxial geogrids. The results also showed that the double reinforcement arrangement consistently yielded better improvement. This study explored preliminarily the feasibility of applying 3D printing technology in geotechnical model tests, which shed light on the understanding of dynamic response of geogrid-reinforced soil and the optimization of geogrids.