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Status report on Step1 of Task A, DECOVALEX-2011
–modeling formodeling for Ventilation Experiment Ventilation Experiment
By Xiaoyan Liu, Chengyuan Zhang and Quansheng Liu
Wuhan Institute of Rock and Soil MechanicsChinese Academy of Sciences (CAS)
April 20-23, 2009G, Korea
DECOVALEX 2011
Task A Force Meeting
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.
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 Research programme
Ventilation Experiment
ssteptep 0 to 1 0 to 11. To consider coupled hydro-mechanical processes (swell & shrinkage effect)
Step 1General model
description
General model description
Governing Equations
Step 1 Simulation results
Conclusion
Discussion
Future work
OutlineOutline
Based on three interacting continua
General model description of multiphase system:General model description of multiphase system:
Capillarity
Two-phase-flow
Liquid phase
Gas phaseVapour
Dry air
Phase exchange
Water
)(Kelg eej s
Governing Equations Governing Equations
For liquidFor liquid
phase exchange(evaporation or precipitation)
lgjg
x
pkk
xt
ppp
s
Sil
j
l
l
lijrl
i
lavl
2/1 ))1(1( SSk rl
volume change change(retention curve)(retention curve)
advection
Governing Equations Governing Equations
For vapourFor vapour
volume change change
j
aavv
vv
j x
MPMPMP
x
v
aavv
vv
av
v
MPMP
MP
mm
m
v
)( lg
gv
vatm
jgx
pkk
xDS
xt
ppp
s
S
t
p
pp
S
v
liv
j
v
v
vijr
jg
i
lavgvg
j
a
aavv
avv
j
v
aavv
vv
aavv
v
x
p
MPMP
MMP
x
p
MPMP
MP
MPMP
M
22
2
v0 p
1b
kk ijvij
v
3.212109.5p
TD
grg Sk
Klinkenberg parameter
phase exchange
ordinary diffusion
SlipKnudsen
effect
advectioncompressibilitycompressibility retention curveretention curve
0a
aagaa
aatm
ijv
ijr
jg
i
lavgg gx
pkk
xDS
xt
ppp
s
S
t
p
pp
S
Governing Equations Governing Equations
For dry airFor dry air
No phase exchange
CouplingCoupling scheme of Flow modelscheme of Flow model
(1) Phase exchange
(2) Saturation-Suction
(3) Different mobility (advection and diffusion effects) of two gas
Governing Equations Governing Equations
For solid deformationFor solid deformation
0)(
iijslgglll
kijkl
j
dFdTBSdpdpx
duD
x
Porous pressure saturation and heat dilatancy
Step Step 11 modellingmodelling
Geometry, Grid Design and Boundary Conditions
Experimental condition in MT test section
200m
34 5 m
10 0m
18 9m
1.3m
Groundwater table
atmgplp 1__
MicroTunnel
Step Step 11 modellingmodelling
Geometry, Grid Design and Boundary Conditions
Experimental condition in MT test section
gplp __
These fourBoundaries:
gHs
V
V
H
gH
lp
l_
Step Step 11 modellingmodelling
Geometry, Grid Design and Boundary Conditions
Experimental condition in MT test section
No Water flow
atm
ppgp vaporairdry
1
_
saturatedvapor pRHp *
Step Step 11 modelingmodeling
Experimental Conditions
Experimental condition in MT test section
Step 1 Step 1 Variables & ParametersVariables & Parameters used in used in simulation simulation
(Munoz, 2003)
0.40 (in our work)
0.165
Hydraulic properties:Variables & Parameters in Step 0
Parameter Value
Solid grain densityKg/m3 2710
Moisture swelling coeff. [-]
0.11*10-4
Poisson ratio [-] 0.27
Young’s Modulus [GPa] 6
Mechanical and hydro-mechanical properties:
Step 1 Step 1 Variables & ParametersVariables & Parameters used in used in simulation simulation
Step Step 11 Simulation results Simulation results
0 200 400 6000.0
0.2
0.4
0.6
0.8
1.0
Time [days from 2002-7-5 to end of Phase1]
26/01/2004
RH
Applied RH of inflow Estimated mean RH
in MT air(Mayor,2007) Simulated RH at 0.67m
05/07/2002
Phase 1 Saturation 270 days
Phase 1 Desaturation 300 days
342 days
342 days
experimental data of ventilation condition and simulation results of RH
Step Step 11 Simulation results Simulation results
Evolution of calculated rock outflow flux
0 100 200 300 400 500 600
0
1
2
3
4
5
Time [days from 2002-7-5 to end of Phase1]
26/01/2004
05/07/2002
Va
po
r flu
x in
to t
un
ne
l [g
/m2 h
]
Step Step 11 Simulation results Simulation results
accumulated water mass out of rock wall
0 100 200 300 400 500 600
0
100
200
300
400
500 481.13Kg
168 days for saturation
05/07/2002
26/01/2004
Time [days from 2002-7-5 to end of Phase1]
calculated value of moisture coming from rock into tunnel
Acc
um
ula
ted
va
po
r m
ass
[kg
]
342 days for saturation
17.74Kg
Step Step 11 Simulation results Simulation results
Calculated total accumulated water mass out of rock wall during Phase 1and its comparison with the monitored data in desaturation period
Step Step 11 Simulation results Simulation results
Simulation results for evolution of porous water pressure
0 1 2 3-100
-50
0
50
100
150
200
saturated zone
Days -990 0 2002.7.5 23 2002.7.28 327 2003.5.28 426 2003.9.4 570 2004.1.26
De
pth
[m
]
porous water pressure [MPa]
unsatzone
Step Step 11 Simulation results Simulation results
Simulation results for evolution of calculated water pressurein some locations around the test section(distance of 0.65m, 0.67m, 1.3m, 2m , 3m and 5 m from MT center)
0 100 200 300 400 500 600
-250
-200
-150
-100
-50
0
26/01/2004
05/07/2002
Time [days from 2002-7-5 to end of Phase1]
wa
ter
pre
ssu
re [
MP
a]
distance from MT center 0.65m 0.67m 1.3m
0 100 200 300 400 500 600
-0.4
-0.2
0.0
0.2
0.4
05/07/2002 26/01/2004
Time [days from 2002-7-5 to end of Phase1]
wa
ter
pre
ssu
re [
MP
a]
distance from MT center 2 m 3 m 5 m
Step Step 11 Simulation results Simulation results
Simulation results for evolution of water saturation in rock near MT
2002.7.5 2002.7.28
2003.5.28 2003.9.24
Step Step 11 Simulation results Simulation results
Simulation results for evolution of water saturation in rock near MT
2004.1.26
0.5 1.0 1.5 2.0 2.5 3.00.0
0.2
0.4
0.6
0.8
1.0
Distance from MT center [m]
Days -990 0 2002.7.5 23 2002.7.28 327 2003.5.28 426 2003.9.4 570 2004.1.26w
ater
sat
urat
ion
Step Step 11 Simulation results Simulation results
Rock displacements around the test tunnel after excavation
0 1 2 3 4 5 6 7 8
0
5
10
15
20
Expansion (swell)
Ra
dia
l dis
pla
cem
en
t [m
m]
Distance from MT center [m]
Days 0 2002.7.5 23 2003.7.28 327 2003.5.28 426 2003.9.4 570 2004.1.26
Compression(shrinkage)
ConclusionConclusion Simulation on the ventilation experiment of Step 1 seems
good.
In the work of Step 0 &Step 1,
getting started and familiarize with the problem
developing our simulation models and numerical code
conducting a comparative analysis of coupled (T)H and (T)HM
modelling
making comparison with experimental observations
making comparison with other teams’ calculation results
We must do more calibration and benchmark test on our
model, especially to make sure the parameters are correct and
model work well.
DiscussionDiscussion
Results are very sensitive to intrinsic permeability, relative
permeability and capillary pressure.
Detailing input information for model is important, e.g.
parameters of properties, initial and boundary conditions.
Sensitivity analysis of vapor diffusion, permeability,
permeability saturation dependence, retention curve will be
benefit to improving models for complex coupled problem.
Future workFuture work
1. Damage and microcracking due to hydromechanical
and chemical effects should be involved in modeling
work.
2. We should improve our model to deal with
heterogeneous permeability field and to consider the
anisotropical evolution of permeability induced by rock
damage.
3. After the 3rd workshop, we will start work for the Step
2 to perform an advanced hydromechanical modelling
up to the end of Phase 2 using parameters back-
calculated from step 1.
Thank you for your attention