Application of Bayesian Methods to the Estimation of Shear Strength Parameters for Slope Stability Analysis of a TSF

Brisbane
Thursday, July 13, 2023, 10:55 AM - 12:35 PM AEST
Technical Talk

Technical Talk

Thursday, July 13, 2023
10:55 AM - 12:35 PM AEST
Join SRK's Senior Geotechnical Engineer, Ignacio Vernengo as he discusses using Bayesian statistics to obtain a more meaningful estimation of shear strength based on available data and prior knowledge of the parameters.

Day 1 | Session 2a

Abstract

This paper covers the estimation of shear strength parameter values for input into slope stability analysis of tailings storage facilities. 

The paper describes the current industry practice of selecting a single (sometimes arbitrary) conservative value for each parameter and proposes to use Bayesian statistics to obtain a meaningful probabilistic evaluation of the strength envelope based on the available data and knowledge of the parameters. 

The concept of prediction intervals was used to define the strength parameters with selected levels of confidence for the analysis. The paper describes the advantages of the Bayesian approach, including mainly the quantification of uncertainty, traceability of the results, incorporation of prior knowledge and update with new information. The paper uses data from a real project to show the shear strength parameter estimation results for both methods and undertakes a 2D limit equilibrium slope stability analysis, highlighting the differences in the results obtained.  

The authors believe that the proposed method is robust and systematic and aligns with the risk approach to tailings management proposed by the Global Industry Standard on Tailings Management (GISTM). The use of the proposed Bayesian approach provides the required inputs to estimate the probability of failure for an embankment, which is considered a preferred outcome when compared with a factor of safety, as it is usually the practice in the industry. A discussion including further work and the potential to use these techniques in other areas of tailings design and operation is also provided.

Authors:

  1. I. Vernengo Lezica
  2. L.F. Contreras

Presenter

Ignacio Vernengo Lezica | Geotechnical Engineer | SRK Australia

Ignacio Vernengo Lezica

Principal Geotechnical Engineer

Ignacio has over 10 years’ experience in geotechnical engineering, specialising in soil mechanics, with specific expertise in tailings storage facilities.

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Co-author

Luis-Fernando Contreras | Geotechnical Engineer | SRK Australia

Luis-Fernando Contreras

Associate Corporate Consultant (Geotechnical Engineering)

Luis-Fernando has over 40 years’ experience in geotechnical analysis and design, tunnel and dam engineering, slope and risk analysis.

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