- EPB tunnelling in mixed geological formations: A case study
- Mariano A. Di ; A. Gens
- IS SEOUL '14
- Year: 2014
PDF |
- Development of a predictive framework for geothermal and geotechnical responses in cold regions experiencing climate change
- C.J. Martin ; A. Gens ; S. Olivilla ; C.H. Fenton ; R.J. Jardine ; S. Nishimura
- Proceedings of the 18th International Conference on Soil Mechanics and Geotechnical Engineering, Paris, September 2-6 2013
- Year: 2013
PDF |
- Determination of the thermal parameters of a clay from heating cell tests
- X.L. Li ; J. Vaunat ; A. Gens ; A. Lima ; E. Romero
- Proceedings of the 18th International Conference on Soil Mechanics and Geotechnical Engineering, Paris, September 2-6 2013
- Year: 2013
PDF |
- A simplified procedure to assess the dynamic stability of a caisson breakwater
- D. Tarrago ; E. Alonso ; A. Gens ; R. Madrid
- Proceedings of the 18th International Conference on Soil Mechanics and Geotechnical Engineering, Paris, September 2-6 2013
- Year: 2013
PDF |
- Analysis of hydro-mechanical processes in a ventilated tunnel in an argillaceous rock on the basis of different modelling approaches
- B. Garitte ; A. Bond ; A. Millard ; C. Zhang ; C. Mcdermott ; S. Nakama ; A. Gens
- Book Title / Journal: Journal of Rock Mechanics and Geotechnical Engineering
- Year: 2013 , Volume: 5
- Rock Mechanics
- Keywords: Hydro-mechanical HM) coupling ; Numerical modelling ; Mont Terri Underground Rock Laboratory (URL) ; Ventilation experiment (VE ; argillite ; water permeability
- Abstract
In this paper, a modelling benchmark exercise from the DECOVALEX-2011 project is presented. The benchmark is based on the performance and results of a laboratory drying test and of the ventilation experiment (VE) carried out in the Mont Terri Underground Rock Laboratory (URL). Both tests involve Opalinus clay. The work aims at the identification, understanding and quantification of mechanisms taking place during the ventilation of a gallery in argillaceous host rocks on one hand and at investigating the capacity of different codes and individuals to reproduce these processes on the other hand. The 4-year in situ VE took place in a 1.3m diameter unlined tunnel and included two resaturation–desaturation cycles. The test area was equipped with over one hundred sensors (including the global water mass balance of the system, relative humidity (RH), water content, liquid pressure, relative displacement and concentration of some chemical species) to monitor the rock behaviour during ventilation. The laboratory drying experiment, carried out before the VE, was designed to mimic the in situ conditions. The work was organized in a progressive manner in terms of complexity of the computations to be performed, geared towards the full hydro-mechano-chemical HMC) understanding of the VE, the final objective. The main results from the modelling work reported herein are tht the response of the host rock to ventilation in argillaceous rocks is mainly governed by hydraulic processes (advective Darcy flow and non-advective vapour diffusion) and that the hydro-mechanical (TM) back coupling is weak. A ventilation experiment may thus be regarded as a large scale-long time pump test and it is used to determine the hydraulic conductivity of the rock mass. PDF |
- Homogenization in clay barriers and seals: Two case studies
- A. Gens ; B. Valleján ; M.T. Zandarín ; M. Sánchez
- Book Title / Journal: Journal of Rock Mechanics and Geotechnical Engineering
- Year: 2013 , Volume: 5
- Rock Mechanics
- Keywords: nuclear waste disposal ; Clay barriers ; Clay seals ; heterogeneity ; Compacted soils ; Coupled analyses ; unsaturated soils
- Abstract
The paper presents two case studies that provide information on the process of homogenization of initially heterogeneous clay barriers and seals. The first case is the canister retrieval test performed in the Aspö Hard Rock Laboratory (Sweden). The heterogeneity arises from the use of a combination of blocks and pellets to construct the engineered barrier. The degree of homogenization achieved by the end of the tests is evaluated from data obtained during the dismantling of the test. To assist in the interpretation of the test, a fully coupled thermo-hydro-mechanical (THM) analysis has been carried out. The second case involves the shaft sealing test performed in the HADES underground research laboratory (URL) in Mol (Belgium). Here the seal is made up of a heterogeneous mixture of bentonite pellets and bentonite powders. In addition to the full scale test, the process of homogenization of the mixture has also been observed in the laboratory using X-ray tomography. Both field test and laboratory tests are successfully modelled by a coupled hydro-mechanical HM) analysis using a double structure constitutive law. The paper concludes with some considerations on the capability of highly expansie materials to provide a significant degree of homogenization upon hydration. PDF |
- Design of jet-grouting for tunnel waterproofing
- M. Arroyo ; A. Gens ; P. Croce ; G. Modoni
- IS ROME '11
- Year: 2011
- Tunneling ; Ground Improvement
PDF |
- Backanalysis of measured movements in ageing tunnels
- .de Santos ; A. Ledesma ; A. Gens
- IS ROME '11
- Year: 2011
- Tunneling ; Numerical & Constitutive Modeling
PDF |
- EPB tunnelling in deltaic deposits: Observations of ground movements
- A. Gens ; A. DiMariano ; M.T. Yubero
- IS ROME '11
- Year: 2011
- Tunneling in Soils
PDF |
- Modelling thermo-hydro-mechano-chemical interactions for nuclear waste disposal
- A. Gens ; L. do N. Guimaräes ; S. Olivella ; M. Sánchez
- Book Title / Journal: Journal of Rock Mechanics and Geotechnical Engineering
- Year: 2010 , Volume: 2
- Rock Mechanics
- Keywords: coupling analysis ; thermo-hydro-mechano-chemical (THMC) analysis ; radioactive waste ; engineered barriers ; bentonite ; cation exchange
- Abstract
A fully coupled thermo-hydro-mechano-chemical (THMC) formulation is described in this paper. Special attention is paid to phenomena likely to be encountered in clay barriers used as engineered barriers in the disposal of nuclear radioactive waste. The types of processes considered in the chemical formulation include hydrolysis, complex formation, oxidation/reduction reactions, acid/base reactions, precipitation/dissolution of minerals and cation exchange. Both kinetics- and equilibrium-controlled reactions are incorporated. The formulation is implemented in a numerical code. An application is presented concerning the performance of a large-scale in-situ heating test simulating high-level radioactive waste repository conditions. PDF |
- Heating pulse tests under constant volume on Boom clay
- A. Lima ; E. Romero ; A. Gens ; J. Muñoz ; X.L. Li
- Book Title / Journal: Journal of Rock Mechanics and Geotechnical Engineering
- Year: 2010 , Volume: 2
- Rock Mechanics
- Keywords: natural Boom clay ; heating pulse test ; pore pressure build-up ; pore pressure dissipation
- Abstract
Boom clay formation is a potential natural host rock for geological disposal of high-level nuclear waste in Belgium. Heating pulse tests with controlled power supply (maximum temperature was limited to 85 °C) and controlled hydraulic boundary conditions were performed under nearly constant volume conditions to study the impact of thermal loading on the clay formation. Selected test results of intact borehole samples retrieved in horizontal direction are presented and discussed. The study focuses on the time evolution of temperature and pore water pressure changes along heating and cooling paths, i.e. pore pressure build-up during quasi-undrained heating and later dissipation at constant temperature. PDF |
- Virtual Calibration Chamber CPT on Ticino sand
- J. Butlanska ; M. Arroyo ; A. Gens
- 2nd International Symposium on Cone Penetration Testing, Huntington Beach, CA, USA. Volume 2&3: Technical Papers, Session 2: Interpretation, Paper No. 11
- Year: 2010
- Site Characterization & In-situ Testing (General)
PDF |
- Liquefaction potential of hydraulic fills
- E.E. Alonso ; A. Gens ; D. Tarrag ; R. Madrid
- 17th International Conference on Soil Mechanics and Geotechnical Engineering (Alexandria)
- Year: 2009
PDF |
- Engineering assessment of jet-grouted structures
- M. Arroyo ; A. Gens
- 17th International Conference on Soil Mechanics and Geotechnical Engineering (Alexandria)
- Year: 2009
PDF |
- Technical session 1e: Analysis
- R. Nova ; A. Murakami ; M. Rouainia ; P. Delage ; A. Gens ; J. Pestana ; D.V. Griffiths ; R. Uzuoka
- 16th International Conference on Soil Mechanics and Geotechnical Engineering (Osaka)
- Year: 2005
- Other Geotechnical
PDF |