Calibration of constitutive parameters by inverse analysis for a geotechnical boundary problem

The finite element method (FEM) has become a standard tool for solving complex problems in geotechnical engineering. Many different advanced constitutive models for fine-grained soils have been developed in recent years, which can consider various phenomena of soil. Generally, the number of constitutive parameters increases with phenomena incorporated in the model, and their determination is one of the key issues in numerical modeling in geotechnics. Normally, experimental data, experience, and back analyses based on engineering judgment are used to arrive at appropriate input parameters for a particular model. However, this procedure is not always satisfactory, especially when the number of required input parameters is large. In this paper, a population-based algorithm has been used to determine the constitutive parameters for a geotechnical boundary value problem, namely a floating stone column foundation under an embankment. Measurements of surface settlements and excess pore-water pressures at different depths are available for calibration. A subsequent statistical assessment of the calibration results is followed to assess the quality of the identified parameters in dependency of the different set of measurements evaluated. As a major result of this research, measures of the utility and reliability of the constitutive models for further predictive computations can be estimated.