Abstract: In this paper a generalized double-layer foundation levee model is built to conduct sensitivity analysis on four major assessment indicators. These indicators include the water head difference between both sides of levee, the duration of warning water level, the thickness of less permeable layer, and the ratio of permeability of strongly permeable layer to that of less permeable layer. The objective weights of these four indicators influencing backward erosion piping are determined. Results indicate that the water head difference and the thickness of less permeable layer (less than 2 m) are two important indicators with relatively large weights. Meanwhile, the objective weights of three indicators, namely, the duration of warning water level, the thickness of less permeable layer, and the ratio of permeability coefficient, vary in different ranges.

Key words: piping danger of levee, weakly permeable strata, strongly permeable layer, ratio of permeability coefficient, sensitivity of weight, dyke with dual foundation layers, generalized model