Mechanistic Model for Self-Healing of Core Cracks in Earth Dams

This paper describes a mechanistic model developed to understand the self-healing mechanism of two types of cracks in impervious cores of earth dams; Type A core cracks which extend from the interior of the core to the downstream filter, and Type B core cracks which extend from the upstream face of the core to the downstream filter. The base soil-crack-filter system is idealized using a four-element one-dimensional continuum to consider various processes in the core and the filter. The model is numerically implemented to predict self-healing in the idealized domain. The model predictions are validated using results from experimental investigations. A parametric study conducted with the model indicates two conditions essential to foster self-healing: a nominal erosion of the base soil, and a seepage velocity in the filter that is less than its critical seepage velocity. This study suggests that the mechanism leading to different rates of self-healing is the interplay of several parameters, viz, characteristics of base soils and filters, geometrical features of cracks, hydraulic conditions, etc. Application of the one-dimensional mechanistic model to a three-dimensional field-scale scenario is demonstrated.