抄録
For deep and/or large excavation of soil with a high ground water level, three-dimensional seepage flow through soil within a cofferdam is a problem. Three-dimensionally concentrated flow lowers the stability against seepage failure more than in the two-dimensional condition. To clarify the three-dimensional seepage failure mechanism, experiments were conducted under three-dimensional flow conditions for various cases, and analyses of FEM seepage flow and stability against seepage failure of soil were carried out. Theoretical critical hydraulic head differences based on the Prismatic failure concept are defined as HPF. From experiments, the hydraulic head differences at an abrupt change of discharge Hd, at the onset of soil deformation Hy, and at failure Hf are considered. The self-stabilizing effects and the method for estimating Hf using the value HPF are discussed.
