Drum Centrifuge Studies of Over Consolidated Slopes

A method is presented for predicting the shear strength mobilized during undrained failure of model slopes in overconsolidated clay. Also long-term failure of model slopes in overconsolidated clay is described. A drum centrifuge was used to conduct these model studies of both short-term and long-term stability. To produce overconsolidated conditions, a kaolin slurry was consolidated in the centrifuge at an acceleration between 150 g and 420 g. After consolidation, the clay deposit was allowed to rebound and a 2-in. (50.8-mm) high, 60° slope was cut around the entire circumference of the drum. Short-term failure was produced by rapidly increasing the speed of the centrifuge until failure occurred. Long-term stability was investigated by maintaining an acceleration lower than that required to cause an undrained failure. In five long-term tests failure occurred after 1 to 8 hours of continous operation.