Non-dimensional formulization of the critical hydraulic head difference for seepage failure of soil in front of sheet piles

Abstract

For the excavation of soil with a high ground water level within a cofferdam, seepage water flows through soil under a hydraulic head difference, H, between up- and downstream sides of a sheet pile wall, and seepage failure is often a problem. Seepage failure sometimes occurs even when a cofferdam has been expertly constructed based on a current design method. There still remain various shortfalls in the theory of the seepage failure of soil. In this paper, the prismatic failure concept 2D (pfc-2D) is first presented, which is one of the conventional methods for designing against seepage failure. Next, the non-dimensional formulization of the critical hydraulic head difference against seepage failure, Hc, is discussed especially in two dimensions. When the prototype (real) and model (test) soils are geometrically similar, we discuss whether or not the non-dimensional formulization for the Hc value is possible. The possibilities of the non-dimensional formulizations of the Hc values in the case of the other flow conditions of 2DC, 3D, and AXS flows are also discussed.