Centrifuge Model Studies on External Stability of Column Type Deep Mixing Ground on Inclined Foundation

Column type deep mixing of improved ground has frequently been used to increase stability of embankments constructed on a soft ground. Model tests and numerical analyses have been carried out to study the behavior and failure pattern of improved ground subjected to embankment load, where the sliding, overturning and bearing capacity failures of the improved ground were studied in the external stability, the shear and bending failures of the deep mixing columns were studied in the internal stability. Almost all studies investigated the stability of the improved ground sitting on a horizontal foundation. However the stability of the improved ground sitting on an inclined foundation has not been well studied. In this study, the external stability of DMM columns on an inclined foundation was investigated by centrifuge model tests. The model test results were compared with the finite element analyses. As a result, the experiment and finite element analyses revealed that the columns showed a rotational failure pattern and the stability of improved ground was almost constant irrespective of the inclination of foundation layer.