Inverse modelling for estimating an interface element properties in soil pipe interaction. - An optimization approach

Abstract

The development of transmitted stresses onto a pipe from the backfill or in-situ soil is not well known for both static and dynamic load cases. This study was aimed at investigating the application of an inverse modelling technique to determine the material parameters of a thin interface layer which lies between the soil and buried pipe during a seismic event to assess the stress transfer. The model uses measured strain values on a pipe of an axial push test. The process of estimation is mathematically known as an inverse problem and is formulated as a non-linear least squares minimization problem coupled with a finite element model for the soil-pipe interaction. The method involves constructing an iterative procedure using an optimization routine in MATLAB and at every iteration, the finite element problem was solved using the finite element program ABAQUS. Finally, the accuracy of the parameter values are examined by using the measured strain values at various different loadings. This research helps to further the understanding of the soil-pipe load transfer system under various loadings and interface layers in finite element analysis.