Probabilistic evaluation of primary consolidation settlement of Songdo New City by using kriged estimates of geologic profiles

The uncertainty in the spatial distributions of consolidation settlement (s _c) and time (t _p) for Songdo New City is evaluated by using a probabilistic procedure. Ordinary kriging and three theoretical semivariogram models are used to estimate the spatial distributions of geo-layers which affect s _c and t _p in this study. The spatial map of mean (μ) and standard deviation (σ) for s _c and t _p are determined by using a first-order second moment method based on the evaluated statistics and probability density functions (PDFs) of soil properties. It is shown that the coefficients of variation (COVs) of the compression ratio [C _c/(1 + e ₀)] and the coefficient of consolidation (c _v) are the most influential factors on the uncertainties of s _c and t _p, respectively. The μ and σ of the s _c and t _p, as well as the probability that s _c exceeds 100 cm [P(s _c > 100 cm)] and the probability that t _p exceeds 36 months [P(t _p > 36 months)] in Sect. 1, are observed to be larger than those of other sections because the thickness of the consolidating layer in Sect. 1 is the largest in the entire study area. The area requiring additional fill after the consolidation appears to increase as the COV of C _c/(1 + e ₀) increases and as the probabilistic design criterion (α) decreases. It is also shown that the area requiring the prefabricated vertical drains installation increases as the COV of c _v increases and as the α decreases. The design procedure presented in this paper could be used in the decision making process for the design of geotechnical structures at coastal reclamation area.