FAILURE OF STEEP REINFORCED SOIL SLOPES

A centrifuge study was undertaken to investigate the failure mechanisms of geosynthetically reinforced steep soil slopes and to evaluate the assumptions in their design. The selected variables in the testing program were the reinforcement spacing, soil strength, and reinforcement strength. Failure in the models was characterized by well-defined shear surfaces through the toe of the slope. The moment of failure was defined by a sudden change in the rate of settlements at the crest of the slope, as monitored from transducers placed on top of the centrifuge models. Well-defined failure surfaces developed, which is in good agreement with current design methods for reinforced slopes based on limit equilibrium. Interpretation of the failure mechanisms in reinforced soil slopes also depends on the distribution of reinforcement forces with depth. However, in contrast to the current design assumptions that failure should initiate at the toe of the reinforced slopes, failure of all centrifuge slope models was observed to initiate at midheight of the slopes.