Many uncertainities are usually encountered in the evaluation of the slope stability of rockfill dams. These include the variabilities in the soil properties such as strength parameters (c', Ø') of core and rockfill materials and permeability etc.; the model error to determine the shear strength and the permeability; and the model error in the analytical method used for stability calculations.
In this thesis, all these uncertainties ar formulated in probabilistic terms, and the effect of the uncertainties on the reliability of rockfill dams is evaluated. The stability analysis used herein considers the three-basic dimensional stability problems with probabilistic framework. The first-order, second-moment analysis is used to calculate the propagation of error from various uncertain parameters to the uncertainty of safety factor. A dam in Korea is used to apply the reliability theory in practice.
The main conclusions drawn from this study are:
1). There is a chance that we overestimate the safety factor by about 10% if we use strength parameters obtained from the laboratory tests without using correction factor accounting for the discrepancy between in-situ condition and laboratory condition.
2). In some case, the probability of failure of a slip section is higher than that of another section, while the deterministic safety factor of the former section is higher than that of the latter. The main reason is that the former section has larger uncertainties than the latter section does.
