Centrifuge Modeling of Geogrid-Reinforced and Rammed Soil-Cement Column-Supported Embankment on Soft Soil

Rammed soil-cement column (RSCC) is a relatively new technology for soft ground improvement. Its properties and construction are different from traditional soil-cement column. The reinforcement mechanism and the effectiveness of RSCC, especially combined with geogrid reinforcement at the bottom of an embankment, are not well understood. In this study, four centrifuge model tests were conducted to investigate the behavior and reinforcement mechanism of geogrid-reinforced, rammed soil-cement column-supported embankments. Displacements, stress concentration ratios, and failure modes of such embankments were obtained in the tests. The test results indicate that RSCC can effectively reduce total and differential settlements and increase global and local stability of embankment on soft ground. Geogrid can reduce the lateral displacement of embankment and facilitate load transfer from the soil to the columns; this reduces the potential of soil yielding and improves the stability of the embankment. Without RSCC5, sliding failure can occur in embankment with or without geogrid reinforcement beneath the embankment. The shear sliding can be circular or noncircular.