Introduction to the Ventilation Experiment (VE) and Task A B. Garitte and A. Gens (CIMNE – UPC)

1. Introduction to the Ventilation Experiment (VE) and Task AB. Garitte and A. Gens (CIMNE – UPC) 3rd DECOVALEX 2011 workshop, 21th of April 2009, , Gyeongju, Korea Dept. of Geotechnical Engineering and Geosciences TECHNICAL UNIVERSITY OF CATALONIA (UPC)

3. The Ventilation Experiment (VE)

4. I greet you all and I invite you to have a meeting in Mont Terri and to visit the Mont Terri facility.

5. Index • Task A • Step 0 (reminder) • Opalinus Clay and the Mont Terri site • Ventilation Test: description and observations • Summary

6. Task A Test case and Benchmark test (J. Hudson) The main objective of the task is to examine the hydromechanical and chemical changes that may occur in argillaceous host rocks, especially in relation to the ventilation of drifts. • Step 0: Identification of relevant processes and of Opalinus Clay parameters. Modelling of the laboratory drying test. • Step 1: Hydromechanical modelling up to the end of Phase 1. • Step 2: Hydromechanical modelling up to the end of Phase 2 using parameters backcalculated from step 1. Advanced features as permeability anisotropy, rock damage and permeability increase in the damaged zone may be considered (not inclusive). • Step 3: Hydromechanical and geochemical modelling of the full test. Conservative transport and one species considered. • Step 4: Hydromechanical and geochemical modelling of the full test. Reactive transport and full geochemical model (optional).

7. Task A • Step 0: Identification of relevant processes and of Opalinus Clay parameters. Modelling of the laboratory drying test. • Step 1: Hydromechanical modelling up to the end of Phase 1. • Step 2: Hydromechanical modelling up to the end of Phase 2 using parameters backcalculated from step 1. Advanced features as permeability anisotropy, rock damage and permeability increase in the damaged zone may be considered (not inclusive). • Step 3: Hydromechanical and geochemical modelling of the full test. Conservative transport and one species considered. • Step 4: Hydromechanical and geochemical modelling of the full test. Reactive transport and full geochemical model (optional).

8. Step 0 (reminder) 10cm is the process by which molecules in a liquid state (e.g. water) spontaneously become gaseous (e.g. water vapour) Evaporation 28cm Relative Humidity is a measurement of the amount of water vapour that exists in a gaseous mixture of air and water 1D Drying Test No flux

9. Step 0 (reminder) Internal report TT conference • Advective liquid water transport • Non advective vapour diffusion 50% Relative humidity [%] 20% 142 days

10. Opalinus Clay and Mont Terri Boom clay (plastic) 230m deep Generic, purpose-built Granite 200m – 450 m deep Generic, purpose-built Rock salt 490m – 800m deep Generic, not purpose-built Opalinus (hard) clay 400m deep Generic, not purpose-built C-O argillite (hard clay) 450m – 520 m deep Site-specific Granite 450m deep Generic, not purpose-built

11. 1: Mont Terri rock laboratory, 400 m beneath the hill 2: Southern entrance of the motorway tunnel Source: Mont Terri website Opalinus Clay and Mont Terri Mont Terri Project • Located in Northern Switzerland • Opalinus clay (shale) • 400 m deep • Operating since 1995 • Generic, not purpose - built

12. Opalinus Clay and Mont Terri

13. Opalinus Clay and Mont Terri Stiff layered Mesozoic clay of marine origin • Overconsolidated clay • Low porosity (±15%) • Water content (±6%) • Density (2.45 g/cm3) • Low permeability (±10-13m/s) • Variation of stiffness (2 to 10 GPa) • UCS (10 to 20 MPa) • Anisotropic material • Temperature • Mechanical (Strength and stiffness) • Hydraulic (?: selfhealing)

14. Ventilation test: description and observations Raise bored horizontal microtunnel Location of the ventilation test

15. Ventilation test: description and observations Location of the ventilation test

16. Ventilation test: description and observations MI niche 1.3m Test section

17. Ventilation test: description and observations • Saturation 1: 11 months • Desaturation 1: 8 months • Saturation 2: 11.5 months • Desaturation 2: 20.5 months

18. Ventilation test: description and observations • Saturation 1: 11 months • Desaturation 1: 8 months • Saturation 2: 11.5 months • Desaturation 2: 20.5 months Phase 0 9/4/98 – 8/7/02 Phase 1 8/7/02 – 29/1/04

19. Ventilation test: description and observations • RH measurements along the test section

20. Ventilation test: description and observations • RH measurements along the test section

21. Ventilation test: description and observations • RH measurements in the “skin layer”

22. Ventilation test: description and observations • Water pans 78.5cm2/pan

23. Ventilation test: description and observations • Mass water balance from RH-in and RH-out (First desaturation phase) 10 cm ring

24. Ventilation test: description and observations • Drilling campaigns

25. Ventilation test: description and observations • RH evolution 16 sensors

26. Ventilation test: description and observations • Water pressure evolution 4_liquid_pressure.xls 24 sensors Water pressure profile before start of controlled ventilation

27. Ventilation test: description and observations • Relative displacements 0.05% -0.15% 8 extensometers

28. Step 1: modelling Isotropic conditions • Plane strain • 0-flow on all borders, excepted on top • Isothermal (T=15º) σ =3.2MPa, pw =1.21MPa 1.21MPa 3.2MPa 4.9MPa 1.85MPa 130m 6.6MPa 2.49MPa pw σ 130m

29. Step 1: case specifications Application of Relative Humidity • Plane strain • 0-flow on all borders, excepted on top • Isothermal (T=15º) 1.3m σ =3.2MPa, pw =1.21MPa 1.21MPa 3.2MPa 4.9MPa 1.85MPa 130m 6.6MPa 2.49MPa pw σ 130m

30. Summary Parameters from step 0 * Modified Van Genuchten

31. Summary • Comparison issues between different teams: • (T)H(M) formulation • Parameter set for Opalinus Clay • Model setup • Model results

32. Summary • Comparison issues between different teams: • (T)H(M) formulation • Parameter set for Opalinus Clay • Model setup • Model results: comparison with measurements