Using a Shallow Mixing Layer to Reinforce Deep Mixing Columns during Embankment Construction

When the deep mixing columns were used to support embankment slope, the columns may fail under either the internal or the external failure pattern, dependent on the strength of columns, soil condition, and loading condition. A shallow layer, produced by shallow mixing method, was proposed to fix and reinforce these isolated columns. In this study, the centrifuge model tests were carried out to simulate the embankment construction on the soft ground, improved by the columns and the shallow layer. The effect of the shallow layer and column strength on increasing the embankment stability can be addressed from the model tests. The failure of isolated columns was compared to that of columns with the reinforcement of shallow layer in terms of internal stability. In addition, by using the test data simple calculations based on limit equilibrium were also carried out to access the failure patterns of column in both internal and external stabilities.