Reconsideration of Creep Length and Application of Elasto-Plastic Finite Element Analysis to Seepage Failure Problems of Foundations under Weirs

Abstract

The stability analysis for seepage failure of foundations under a weir has been conducted by means of the creep length derived from the creep theory. As this is a simple method developed empirically, it does not show the deformation process of the foundations along with the increase of the water head between upstream and downstream of the weir. In the present study, series of model tests of seepage failure were carried out and the test results were applied to elasto-plastic finite element analysis to reconsider the seepage failure problems. The obtained model test results showed that the critical water head for seepage failure could not be correctly evaluated by the creep length in the previous theory. The newly proposed finite element analysis in which the seepage force is treated as external force to elasto-plastic finite element analysis appropriately reproduced the model test results regardless of its mesh size. The analysis results suggested the applicability of Terzaghi's method to evaluate the critical water head for seepage failure of foundations under a weir.