Calibration of soil constitutive laws by inverse analysis

When a model is calibrated by iteratively changing the estimates of the model input parameters until the value of an objective function, which quantifies the match between observed and computed results, is minimized we are dealing with inverse analysis. The major advantage of an inverse modelling is the automatic and objective calculation of the parameter values that produce the best fit between measured data (often called observations) and computed results. The main difficulties are related to the complexity of most numerical models, which sometimes cause problems of non-uniqueness and instability of the solution or insensitivity of the results to changes in the values of the parameters. This chapter presents the main aspects related to inverse analysis techniques used to calibrate the parameters of soil constitutive laws. It comprises three main sections respectively dealing with: a computer code designed to allow inverse modeling posed as a parameter estimation problem; the use of inverse analysis to calibrate soil models from results of laboratory experiments; an inverse analysis procedure to update the design predictions of a supported excavation system using monitoring data collected during construction