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Comparative study of the effects of three data-interpretation methodologies on the performance of geotechnical back analysis |
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| Authors: | Ze-Zhou Wang Siang Huat Goh Chan Ghee Koh Ian FC Smith |
| Institution: | 1. Department of Civil and Environmental Engineering, National University of Singapore, Block E1A, #07-03, No.1 Engineering Drive 2, 117576 Singapore;2. Department of Civil and Environmental Engineering, National University of Singapore, Block E1A, #07-03, No.1 Engineering Drive 2, 117576 Singapore
Future Cities Laboratory, Singapore-ETH Centre, 1 Create Way, CREATE Tower, #06-01, Singapore, 138602 Singapore;3. Future Cities Laboratory, Singapore-ETH Centre, 1 Create Way, CREATE Tower, #06-01, Singapore, 138602 Singapore Applied Computing and Mechanics Laboratory (IMAC), School of Architecture, Civil and Environmental Engineering (ENAC), Swiss Federal Institute of Technology (EPFL), Lausanne, Switzerland |
| Abstract: | Back analysis can provide engineers with important information for better decision-making. Over the years, research on back analysis has focused mainly on optimisation techniques, while comparative studies of data-interpretation methodologies have seldom been reported. This paper examines the use of three data-interpretation methodologies on the performance of geotechnical back analysis. In general, there are two types of approaches for interpreting model predictions using field measurements, deterministic versus population-based, both of which are considered in this study. The methodologies that are compared are (a) error-domain model falsification (EDMF), (b) Bayesian model updating and (c) residual minimisation. Back analyses of an excavation case history in Singapore using the three methodologies indicate that each has strengths and limitations. Residual minimisation, though easy to implement, shows limited capabilities of interpreting measurement data with large uncertainty errors. EDMF provides robustness against incomplete information of the correlation structure. This is achieved at the expense of precision, as EDMF yields wider confidence intervals of the identified parameter values and predicted quantities compared with Bayesian model updating. In this regard, a modified EDMF implementation is proposed, which can improve upon the limitations of the traditional EDMF method, thus enhancing the quality of the identification outcomes. |
| Keywords: | back analysis Bayesian updating excavation finite element analysis observational method parameter identification |