Abstract #
This paper explores the potential substitution of the Hoek-Brown (HB) failure model with the Mohr-Coulomb (MC) model in the stability analysis of rock masses. It investigates the conditions under which the linear MC model can provide results comparable to the non-linear HB model. Through a numerical analysis using the GEO5 FEM software, the study emphasizes the critical importance of selecting appropriate stress ranges for the equivalence of the two failure criteria, particularly in slope stability problems.
Technical Relevance #
This document is essential for geotechnical engineers and researchers involved in rock mechanics and slope stability analysis. The comparison between Hoek-Brown and Mohr-Coulomb criteria highlights key considerations when choosing a failure model in finite element analysis, particularly in scenarios where accurate prediction of rock mass behavior is crucial.
Target Audience #
The document is targeted at geotechnical engineers, researchers, and professionals who use finite element analysis for rock stability assessments. It is particularly relevant for those working on projects involving rock slopes and underground excavations, where the choice of failure criteria can significantly impact the analysis outcomes.
Software and Methodology #
The analysis was conducted using the GEO5 FEM software, a tool designed for geotechnical problem-solving. The study involves a detailed examination of the Hoek-Brown and Mohr-Coulomb models, focusing on their application in the stability analysis of rock masses. The methodology includes the derivation of equivalent shear strength parameters for the Mohr-Coulomb model and a comparison of results obtained from both models in a simulated oedometric test and slope stability analysis.
Process Description #
The document begins with an introduction to the Hoek-Brown and Mohr-Coulomb failure criteria, followed by a detailed derivation of equivalent shear strength parameters. A numerical analysis is performed on an oedometric test model to investigate the influence of different stress ranges on the equivalence of the two models. The study also includes a slope stability analysis, comparing the safety factors and potential slip surfaces predicted by both models using the GEO5 FEM software.
Main Findings #
The study concludes that the Mohr-Coulomb model can provide comparable results to the Hoek-Brown model if the stress ranges are carefully selected. However, the Hoek-Brown model remains superior for complex rock mass conditions, particularly in slope stability analysis, where the non-linear behavior of rocks is more accurately captured. The research also demonstrates that an incorrect choice of stress range in the Mohr-Coulomb model can lead to significant deviations in predicted outcomes.
Practical Applications #
The findings from this study are directly applicable to the stability analysis of rock slopes and underground excavations. Engineers can use these insights to make informed decisions about the selection of failure criteria in FEM analysis, ensuring more accurate predictions of rock mass behavior under various stress conditions.
Limitations and Considerations #
The document acknowledges that while the Mohr-Coulomb model is simpler and widely used, its application is limited to specific stress conditions that must be carefully defined. The Hoek-Brown model, although more complex, provides a more accurate representation of rock mass behavior, particularly in heterogeneous or highly disturbed rock masses.
Conclusions #
The study concludes that while the Mohr-Coulomb model can be an effective substitute for the Hoek-Brown model under certain conditions, the latter remains the preferred choice for more complex analyses. The research highlights the importance of selecting appropriate stress ranges when using the Mohr-Coulomb model and suggests that direct application of the Hoek-Brown model is advisable for more accurate and reliable results in slope stability analysis.
Related Resources #
Further reading includes studies on the application of the Hoek-Brown criterion in other geotechnical scenarios, as well as case studies comparing different FEM software tools. Exploring additional resources on the calibration of rock mass parameters for FEM analysis can provide deeper insights into the practical implementation of these models.
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