Abstract
Physical meaning of the creep length calculated from the creep theory has been discussed on the stability analysis for seepage failure of foundations under weirs. It was indicated that these creep theories couldn't predict critical water head under weirs and the Terzaghi's method could predict seepage failure under weirs in previous studies. However, these previous studies were used Toyoura sand only as the ground material. In this study, seepage failure model experiments with two cases of weir shape were conducted. Three types of silica sands as the ground materials were demonstrated. Creep theory, Terzaghi's method and critical velocity methods were reexamined by these model experiments. These previous formulae couldn't express results of model experiments of large particle size of silica sand. Modified Terzaghi's method to model the influence of diameter of void was suggested in this study. It was observed that the modified Terzaghi's method predicted the results of model experiments well.
