Stability Analysis of Embankments on Soft Ground

A simple and convenient semi‐analytical procedure is presented to calculate the factor of safety of embankments constructed on soft clay. Stability numbers $N_1$ and $N_2$ are developed for the normalized foundation strength and normalized embankment strength, respectively. The factor of safety (in terms of overall moment equilibrium) can be computed as the sum of two components, each equal to the product of the respective stability number and the corresponding normalized strength. The relative importance of the foundation strength and the embankment strength in contributing to the factor of safety can also be assessed during the computation. The proposed method assumes short term undrained response of the soft clay foundation. It can deal with cases where the undrained shear strength of the soft clay varies with depth, and where the embankment possesses both cohesion and internal friction. The application of the method is illustrated by several examples and the results are compared with those obtained from a computer analysis.