| In March of 1994, a slope failure, which this research presumes to be a flow liquefaction event, occurred in the coal ash tailing facility at the TransAlta Wabamun generating station. In-situ testing carried out in the ash deposits indicate the ash is a weak, highly compressible granular material that may be weakly cemented. Laboratory testing of reconstituted samples defined state boundaries and the relationship between shear wave velocity, void ratio and effective confining stress. The method described by Cunning (1994), predicts the in-situ response of the material to be strain hardening. This inconsistency with the proposed failure mechanism is discussed. As experience given in the literature with lightly cemented carbonate sands indicates that cementation can cause material to become brittle and strain softening, this report concludes there is a need for further work to understand cementation in granular materials and the possible role of cementation in the Wabamun ash deposits. |
