Soil characterisation of an artificial island accounting for heterogeneity

摘要

The heterogeneous nature of soils and other geo-materials results in uncertainty in design and so it is important to incorporate this heterogeneity in analyses of geo-strucrure performance. However, before analysing the geo-structure itself, it is first necessary to statistically characterise the site in terms of appropriate soil properties. This paper focuses on the description of this first stage in the analysis by presenting a case study. Numerous artificial sand islands were designed and constructed in the Canadian Beaufort Sea, for use as hydrocarbon exploration platforms, in the 1970's and 1980's. For some of these islands, extensive Cone Penetration Test (CPT) data are available for characterising the hydraulically placed sands and for investigating the general factors affecting the in situ density. This paper investigates data from one of these islands. An existing methodology to statistically evaluate CPT data in terms of state parameter is described, the aim being to characterise the deposited sands in terms of state parameter statistics (mean, standard deviation, probability density function and scale of fluctuation). From the results obtained, a discussion on the factors influencing the quality of the fill in terms of in-situ density is presented.