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

The Ventilation Experiment (VE)

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

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

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).

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).

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

Step 0 (reminder) Relative humidity [%] 20% 50% 142 days CASCEAJAEAQuintessaUoE  Advective liquid water transport  Non advective vapour diffusion Internal reportTT conference

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

Overconsolidated clay Low porosity (±15%) Water content (±6%) Density (2.45 g/cm 3 ) Low permeability (± m/s) Variation of stiffness (2 to 10 GPa) UCS (10 to 20 MPa) Anisotropic material Temperature Mechanical (Strength and stiffness) Hydraulic (?: selfhealing) Stiff layered Mesozoic clay of marine origin Opalinus Clay and Mont Terri

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

Ventilation test: description and observations Location of the ventilation test

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

Ventilation test: description and observations  Saturation 1: 11 months  Desaturation 1: 8 months  Saturation 2: 11.5 months  Desaturation 2: 20.5 months

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

Ventilation test: description and observations  RH measurements along the test section

Ventilation test: description and observations  RH measurements along the test section

Ventilation test: description and observations  RH measurements in the “skin layer”

Ventilation test: description and observations 78.5cm 2 /pan  Water pans

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

Ventilation test: description and observations  Drilling campaigns

Ventilation test: description and observations  RH evolution 16 sensors

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

Ventilation test: description and observations  Relative displacements 8 extensometers 0.05% -0.15%

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

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

Summary CASCEAJAEAQuint.UoE Physical Solid grain densityρ s [kg/m3] Porosityφ Hydraulic Intrinsic permeabilityk [m2] 7.5E-202E E-191.9E-20 Dynamic viscosityμ [Pa.s]1E-32.9E-4 Liquid relative permeabilityλ’ Vapour diffusion coefficient 6E-6 5E-6 Mechanical Young modulusE [GPa] Poisson coefficientν Friction angleφ [º] Cohesionc [MPa] Hydro-Mech. coupling Suction bulk modulusK s [GPa] Air entry value (retention curve)P 0 [MPa] Shape parameter (retention curve)λ Maximum suction (retention curve)*P s [MPa]700 Second shape parameter (retention curve)*λsλs 2.73 Residual and maximum saturation (retention curve)S rl – S rs 0 – * Modified Van Genuchten Parameters from step 0

Summary Modelling teamCASCEAJAEAQuintessaUoE PersonLiu XiaoyanAlain Millard Shigeo Nakama Alex BondChris McDermott On behalf ofCASIRSNJAEANDA CountryChinaFranceJapanUK  Comparison issues between different teams:  (T)H(M) formulation  Parameter set for Opalinus Clay  Model setup  Model results

Summary Modelling teamCASCEAJAEAQuintessaUoE PersonLiu XiaoyanAlain Millard Shigeo Nakama Alex BondChris McDermott On behalf ofCASIRSNJAEANDA CountryChinaFranceJapanUK  Comparison issues between different teams:  (T)H(M) formulation  Parameter set for Opalinus Clay  Model setup  Model results: comparison with measurements