Calculating Reliable Engineering Geological Model through Stochastic Co-Simulation Applied to CPTu Data

Abstract

To perform a geotechnical reliable design, the spatial variability and the uncertainties related to the adopted engineering geological model (EGM) must be taken into account. However, any conceived EGM is characterized by uncertainties covering (1) the bias in the mathematical expression that transforms the measured parameters into design ones; and (2) the uncertainty associated with the variability of the soil and rock parameters in the prediction equations. Hereinafter, the sequential Gaussian co-simulation method (SGCS) has been applied to propagate the uncertainty in the calculation of the undrained shear resistance su from measured CPTu profiles (i.e., qc, fs, u2) through a linear model of co-regionalization. The studied area is located in the Po River alluvial plain (Bologna Province, Italy), where the mixture of silts, sands, and clays gets thicknesses of hundreds of meters. These heterogeneous deposits have been mechanically characterized through a 3D EGM to be used in reliability-based designing.