A model for predicting the probability of liquefaction induced by the ocean storm-wave is developed. Many uncertainties are encountered in the analysis of liquefaction potential for the foundation of offshore structures: (1) the storm-wave duration, (2) the effect of reconsolidation, (3) the effect of partial drainage, etc. These uncertainties are formulated in probabilistic terms and used to assess the risk of liquefaction for a given offshore site.
The model developed is applied to the Ekofisk oil storage tank in the North Sea installed in 1973. Reasonable comparison is obtained between the probabilities of liquefaction obtained and the results of deterministic models or the field observations. Among the uncertainties encountered it is revealed that the effect of reconsolidation is the most critical factor.
Since many problems are encountered in the deterministic models developed so far, the probabilistic model developed in this thesis might be a reasonable alternative tool and can be used in the design of new offshore structures.