Geosynthetic reinforced embankments on soft clay foundations: predicting reinforcement strains at failure: Fid-Bau Portal

Geosynthetic reinforced embankments on soft clay foundations: predicting reinforcement strains at failure

Hinchberger, S.D. / Rowe, R.K.

A method for calculating the allowable reinforcement strains for embankments constructed on soft clayey foundations having increasing undrained shear strength with depth is presented. The method was tested against the observed performance of a embankment case history. Overall, factors such as the undrained shear strength profile strongly influenced the reinforcement strains at failure. It was generally found that the behaviour of reinforced embankments on soft clayey foundations is dominated by plastic flow within the foundation and the resultant kinematics of failure. Elastic properties of both the foundation and embankment material did not have a significant impact on calculated reinforcement strains at failure. It is recognized, however, that a relatively narrow range of fill properties were investigated here and that further research into the influence of fill properties on reinforcement strains is warranted. The focus of this paper was on failure of reinforced embankments due to excessive displacement. It is noted that modes of failure such as pullout of the reinforcement, and sliding along the foundation-fill interface did not govern failure in the finite element analyses utilized in developing the simplified procedure. These other potential failure modes must be assessed during the design of reinforced embankments on soft clayey foundations. The method of analysis proposed is simplified and approximately takes into account the effects of embankment side slopes and fill unit weight on the reinforcement strains at failure. Combined with simplified methods of analysis (e.g. slip circle) the allowable reinforcement strains can be used to select suitable reinforcement. Finally, two examples were used to illustrate the selection of reinforcement for embankments on soft clayey foundation soil with increasing strength with depth.