Sensitivity analysis of the model response in mechanized tunneling simulation – A case study assessment

Abstract

In this article, a sensitivity analysis has been conducted on numerical simulation of shield supported mechanized tunnel excavation in soft soil. Thus, a numerical model is generated to simulate the tunnel excavation process by slurry shield machine using commercially available Finite Element (FE) code, PLAXIS2D. The model calibration and verification are conducted on the basis of real measurements of Western Scheldt tunnel in the Netherlands. Hardening Soil model with small-strain stiffness (HSsmall) is applied in numerical simulation to concern the staged construction process of the problem. Both local and global sensitivity analyses methods are carried out in this paper to evaluate the uncertainties of constitutive model parameters. Since the numerical implementation of global sensitivity analysis requires intensive evaluations of FE-model, a practical meta-modeling technique is employed to provide reliable approximation of model response. Thereafter, a parameter optimization technique (back analysis) is conducted to find the most desired values of selected sensitive parameters which provide a good agreement between numerically obtained displacements and the measured data.