Probabilistic evaluation of spatial distribution of secondary compression by using kriging estimates of geo-layers

Abstract

This paper presents a procedure for evaluating the spatial uncertainty in the secondary compression (s(s)) using a probabilistic method. In order to evaluate the spatial distribution of ss, the spatial maps of three geo-layers (the thickness and depth of the consolidating layer, the bottom elevation of the reclaimed sandfill) are estimated by using kriging techniques. For all three geo-layers considered in this study, the ordinary kriging is found to give more reliable estimates than the kriging with a trend and simple kriging. It is observed that the coefficients of variation (COVs) of C-alpha/C-c and C-c/(1 + e(o)) have similar influences on the COV of s(s). It is also shown that the COV of c(v) has less effect on the COV of s(s) than the COVs of C-alpha/C-c and C-c/(1 + e(0)) although the COV of c(v) is larger than that of C-alpha/C-c and C-c/(1 + e(0)). The COV of ss evaluated by considering all the COVs of soil properties is 0.420, which is 1.4-2.7 times larger than that determined by considering the COV of an individual soil property separately. It is observed that the area exceeding a design criterion increases as the COV of C-alpha/(1 + e(0)) increases and the probabilistic design criterion (alpha) decreases. For Songdo New City, the area ratio decreases from 0.47 for alpha value of 0.05 to 0.04 for a value of 0.45. The design procedure presented in this paper could be used in the decision making process for a geotechnical engineering design. Crown Copyright (C) 2011 Published by Elsevier B.V. All rights reserved.