Abstract
Element testing of soft soils is challenging due to the large strains attained in the pre-failure range. Besides the heterogeneity of natural samples, the set-up configuration is the main driving factor for non-homogenous response. Stress, strain and pore pressure non-uniformities induced by the loading system affect the observed behaviour and complicate proper interpretation of the results. Among the difficulties encountered in the interpretation of laboratory data, the unexpected decrease of the stress ratio frequently observed on Dutch organic soft clays on the wet side of critical state is investigated by numerically back-analysing the triaxial test set-up. A 3D finite element simulation using an advanced constitutive model for soft clays developed at TU Delft was performed to clarify the nature of the response. The results indicate that a decrease in the deviatoric stress up to critical state may be interpreted as a true feature of the soil response. However, the response at large strains is very much influenced by the triaxial shear apparatus, in particular, by the rotation of the top cap which triggers geometrical instability. Practical recommendations are given to limit the effects of the set-up configuration on the determination of the undrained shear strength to be used for field applications.
Original language | English |
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Title of host publication | Proceedings of the 10th European Conference on Numerical Methods in Geotechnical Engineering |
Editors | Lidija Zdravkovic, Stavroula Kontoe, Aikaterini Tsiampousi, David Taborda |
Publisher | International Society for Soil Mechanics and Geotechnical Engineering |
Number of pages | 6 |
DOIs | |
Publication status | Published - 2023 |
Event | NUMGE 2023: 10th European Conference on Numerical Methods in Geotechnical Engineering - Imperial College London, London, United Kingdom Duration: 26 Jun 2023 → 28 Jun 2023 https://www.imperial.ac.uk/numerical-methods-in-geotechnical-engineering/ |
Conference
Conference | NUMGE 2023 |
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Country/Territory | United Kingdom |
City | London |
Period | 26/06/23 → 28/06/23 |
Internet address |
Keywords
- Soft soils
- Triaxial test
- Constitutive modelling
- Finite element simulation
- Experimental set-up