Large-scale Field Tests of the Performance of Geogrid-reinforced Piled Embankment over Soft Soil

When constructing superstructures on soft soils, geogrid-reinforced embankments and pile-supported embankments are used widely to improve the soft foundation and prevent issues including excessive settlements and large lateral displacements, so it is crucial to understand and evaluate their performance systematically. This study focuses on a case of piled embankments for a motor-racing circuit under construction in China. Two large-scale field tests of pile-supported embankments with and without reinforcement were carried out to investigate the effect of geosynthetic reinforcement on the improvement of embankments. During long-term monitoring, instruments in the test sites measured earth pressures, settlements, lateral displacements, and pore water pressures, and the performances of the reinforced or unreinforced embankments were examined. Test results from the two test sites under similar loading are compared, and it is concluded that the geosynthetic-reinforcement considerably influences the improvement of load transfer and diminishment of total and differential settlements. The lateral restraint provided by the geogrids also reduced the lateral soil displacement and the influence of subsoil depth. The smaller excessive pore water pressures in the site with reinforcement were associated with the enhanced load transfer due to the geogrids. This study provides an important reference for the design and construction of this circuit and other related projects.