Centrifuge tests of embankments on strengthened and unstrengthened clay foundations

Centrifuge tests were conducted to study the behaviour of embankments on soft clay foundations prepared with an overconsolidated crust over normally consolidated kaolin clay. Tests were performed with embankments constructed during flight in stages with measurements of pore pressures at selected locations and displacements using a marker grid. This Paper concentrates on two tests in the series. One test was performed with the clay foundation strengthened using granular columns; the other test had an untreated foundation. In the test using an untreated foundation the embankment failed at a height of 11·6 m. The strengthened foundation supported an embankment of 13 m without failure. Large lateral displacements were measured in unstrengthened clay during consolidation periods and it was found that large displacement increases are a good indicator of a factor of safetybelow about 1·3. At corresponding loadings the use of strengthened foundations decreased lateral and vertical movements by about 50%. Total st...