status report on step1 of task a, decovalex-2011 modeling for ventilation experiment –modeling for...

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


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


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


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




gplp __

These fourBoundaries:

gHs

V

V

H

gH

lp

l_




No Water flow

atm

ppgp vaporairdry

1

_

saturatedvapor pRHp *

Step Step 11 modelingmodeling

Experimental Conditions


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


Evolution of calculated rock outflow flux

0 100 200 300 400 500 600

0

1

2

3

4

5


26/01/2004

05/07/2002

Va

po

r flu

x in

to t

un

ne

l [g

/m2 h

]


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


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


Calculated total accumulated water mass out of rock wall during Phase 1and its comparison with the monitored data in desaturation period


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


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


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


wa

ter

pre

ssu

re [

MP

a]

distance from MT center 2 m 3 m 5 m


Simulation results for evolution of water saturation in rock near MT

2002.7.5 2002.7.28

2003.5.28 2003.9.24


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


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

status report on step1 of task a, decovalex-2011 modeling for ventilation experiment –modeling for...

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