Analysis of hydro-mechanical processes in a ventilated tunnel in an argillaceous rock on the basis of different modelling approaches

B Garitte, Alex Bond, A Millard, Christoper McDermott, C Zhang, S Nakama, A Gens

Research output: Contribution to journalArticlepeer-review

Abstract / Description of output

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 1.3mdiameter 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 that 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.
Original languageEnglish
Pages (from-to)1-17
Number of pages17
JournalJournal of Rock Mechanics and Geotechnical Engineering
Issue number1
Publication statusPublished - Feb 2013

Keywords / Materials (for Non-textual outputs)

  • Hydro-mechanical (HM) coupling
  • Numerical modelling
  • Mont Terri Underground Rock Laboratory (URL)
  • Ventilation experiment (VE)
  • Argillite
  • Water permeability


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