Evaluation of the parameters influencing self-healing in earth dams

This paper describes the experimental methods developed to understand the self-healing or progressive erosion of core cracks in earth dams. Concentrated leaks through two types of core cracks are simulated experimentally in flow cells of different configurations. Results of experimental investigations indicate that the current empirical filter criterion for base soils with fines content more than 85%, which stipulates that (D_15F/d_85B) should be less than 9, is conservative. However, analysis of experimental results suggests that the (D_15Fd_85B) ratios can not indicate the rate of self-healing or progressive erosion. It also leads to a conclusion that mechanistic understanding, rather than another improved empirical criterion, may be needed for quantitative prediction of self-healing or progressive erosion. In this study, we identified two groups of quantitative parameters influencing the mechanism of self-healing: (1) characteristics of base soils and filters, and (2) hydraulic, geometric, and physicochemical conditions. Experimental methods are presented to evaluate these parameters for which no standardized methods are reported in the current literature.