Centrifugal modeling of a geogrid-reinforced embankment on soft subsoil

A centrifugal model test was performed to investigate the behavior of a geogrid-reinforced embankment on soft subsoil. The prototype was a reinforced embankment with four-lane driveways using lime-stabilized soil as backfill, which was 4-meter high, 26-meter wide, and over 20-meter thick soft silty clay. The slope angle of this embankment was 1.5(H):1.0(V). One plastic window screen by removing 2/3 of its strings was used to simulate the prototype geogrid while sand drains with 5-mm diameter were used to simulate prototype prefabricated vertical drains. Displacements, soil pressures, and pore water pressures were measured during the test. Test results showed: (1) the settlement estimated from the markers installed on the front face of the foundation was approximately 90% of that measured by displacement sensors; (2) the elastic displacement of the subsoil was approximately 11% of the total displacement; (3) the total settlement in the prototype embankment was 1.7 m and 300-mm wide cracks occurred at the central portion of the embankment.