A Simplified Method of Incorporating Testing Data and Monitored Behaviour for Predicting Surface Settlement Using Bayesian Back Analysis

This study presents a simple consolidation analysis method to predict surface settlement using Bayesian back analysis for embankments built over soft soil. Simplification of the geotechnical model and parameters is common in engineering practice; however, review of the performance to verify and update the prediction is seldom. Oversimplification however may not capture the appropriate conditions for reliable settlement prediction. Bayesian back analysis provides a way to update the adopted prior parameters using monitored data. Parameters such as the compression ratio, recompression ratio, creep strain rate, and the coefficient of compressibility were treated stochastically as random variables. Both a nine-layered and three-layered model were analysed for comparison. The analysis used simplified models to show the surface settlement was well predicted utilising about 117 to 215 days of observed data. The settlement data was used to update the selected parameters through Bayesian back analysis to fit the entire time-settlement history.