Upload
others
View
1
Download
0
Embed Size (px)
Citation preview
AGENCE NATIONALE POUR LA GESTION DES DÉCHETS RADIOACTIFS© Andra
G. Armand, A. Noiret, J. Zghondi, R. de La Vaissière, N. Conil, J. Morel, F. Bumbieler
Rock mechanics of the Callovo-Oxfordianclaystone at the Meuse/Haute-Marne
Underground Research Laboratory and consequences for CIGEO repository design
DRD/MFS/14-0038
Symposium « Rock Mechanics and Rock Engineering of Geological Repositories in Opalinus
Clay and Silmilar Claystone »
AGENCE NATIONALE POUR LA GESTION DES DÉCHETS RADIOACTIFS© Andra© Andra
Legal Framework in France
The 1991 Waste Act
Creation of « Andra » as a public independent body
3 research areas for High Level Long-lived Waste: partitioning/transmutation; long term storage; geologic disposal
2005: Feasibility assessment of safe geological disposal in Callovo-Oxfordian claystone layer (Meuse/Haute-Marne URL)
The 2006 Programme Act: Reduce/avoid the burden on future generations
Reduce volume and harmfulness of wastes
SF reprocessing + waste treatment and conditioning
Reference option for final waste that can no longer be treated: geological repository with respect to reversibility (100 y at least)
Application: 2015; Operation: 2025
Continue research on interim storage (Andra) and partitioning/transmutation (CEA) and on a complementary basis.
Cigéo Project
DRD/MFS/14-0038
AGENCE NATIONALE POUR LA GESTION DES DÉCHETS RADIOACTIFS© Andra© Andra
Architecture of CIGEO Project
Excavation ActivitiesNuclear
Activities
Surface facilities will be split in 2 parts
Ramps for waste packages &
general service
HL LLW disposal zone
Shafts for construction
and ventilation
DRD/MFS/14-0038
Underground facility : cells will be added progressively as the operation progresses until they reacha total maximum area of about 15 km2, after about 100 years
CIGEO: Industrial Center for Geological Disposal
AGENCE NATIONALE POUR LA GESTION DES DÉCHETS RADIOACTIFS© Andra© Andra
Zoom on the IL-LLW disposal cell
Length: 400 m
Excavated diameter: 9-11 m
2x2 or 3x3 packages
No. of containers: 800-1,900
DRD/MFS/14-0038
AGENCE NATIONALE POUR LA GESTION DES DÉCHETS RADIOACTIFS© Andra© Andra
Zoom on the HLW disposal cell
Length 80 m
Diameter: 70 cm
No.of containers: 7-20
(for 40 m)
Package of vitrified waste (CID-V)
DRD/MFS/14-0038
AGENCE NATIONALE POUR LA GESTION DES DÉCHETS RADIOACTIFS© Andra© Andra
Needs in geomechanic
Specific feature of such projectUnderground nuclear facility
Long operational life time
Size (length of drift,…)
DRD/MFS/14-0038
Need a good understanding of rock and structure interaction The Callovo Oxfordien THM behaviorThe structure behavior (concrete,…)It is necessary to take into account the consequences of the construction method (velocity of digging, time between digging and installation, type of material as structure
Design of different elements of the repository
Input for the performance assessment calculation
AGENCE NATIONALE POUR LA GESTION DES DÉCHETS RADIOACTIFS© Andra© Andra
Geomechanical research at the URL
The performance/safety assessment and technology demonstrationare the main objectives of research programs. In geomechanic:
To study hydro mechanical behavior of claystone during drift and shaft excavation (short and long term behavior)
Impact of digging and support method Orientation of drift
To characterize the Excavation Damaged Zone (EDZ)To characterize the Thermo Hydro Mechanical behaviorTo perform sealing experimentsTo study the impact of gas transfert in the rock/EDZ/seals
EDZ characterization for safety assessment calculation
HM behavior to design support of the repository drifts
DRD/MFS/14-0038
In situ experiment serve for demonstration issueIn situ measurements are compared with numerical modeling and useful to validate and develop HM model
AGENCE NATIONALE POUR LA GESTION DES DÉCHETS RADIOACTIFS© Andra
The Callovo Oxfordian claystone
DRD/MFS/14-0038
AGENCE NATIONALE POUR LA GESTION DES DÉCHETS RADIOACTIFS© Andra© Andra
Paris
URL
226 km
The Callovo-Oxfordian argillite at the MHM site (Bure)
• Age: 155 million year• Depth at the site: ~500 m• Thickness at the site: ~130 m
• Mineralogy: ~ 45% clay + carbonates and silicates
• low water content• No free water, no water flow• Diffusive transfer only• Retention capacity
DRD/MFS/14-0038
AGENCE NATIONALE POUR LA GESTION DES DÉCHETS RADIOACTIFS© Andra© Andra
Axial displacement
Dev
iato
ricst
ress
(1-
3)
Elasticity
Damage
Failure
Hoxha,2004
Rock properties of the COX
Callovo Oxfordian claystoneproperties at the 490 m level:
Mineralogy:50-55% clay minerals 20-25% carbonatearound 25% quartz silts
Very low permeability (5.10-20 m²)Short-term behavior, triaxial test: non linear and post-peak depending on 3
Long term behavior, uniaxial creep test:
Creep strain rate increases non-linearly with the applied deviatoric stressCreep rate (Andra 2005):
4.10-12 < creep rate <1.60.10-12
(test duration 1 to 3 years)
Long-term behavior according to the modified Lemaître’s model
DRD/MFS/14-0038
Rock parameter Ind. ValueBulk specific gravity 2.39 g/cm3
Porosity n 16 2%
Young modulus EE///E
4000 1470 MPa1.2 to 1.5
Poisson Ratio 0.29 0.05Uniaxial compressivestrength UCS 21 6.8 MPa
Hoek & Brown criteriaSm
c (MPa)
0.432.533.5
Intrinsic permeability k 5 10-20 m2
Water content w 7.2 1.4 %
Residual
AGENCE NATIONALE POUR LA GESTION DES DÉCHETS RADIOACTIFS© Andra
HM behavior of drift (at the main level of the URL)
DRD/MFS/14-0038
AGENCE NATIONALE POUR LA GESTION DES DÉCHETS RADIOACTIFS© Andra© Andra
Experimental strategy for the study of drift behaviour
1- Use the underground laboratory for observing real behavior of drift under natural conditions
Each drift excavation in the URL is a geomechanical experiment in itself
2- Sequencing of drift construction to highlight the role of support/excavation methods
Start with "soft" support drift to study the behavior of COX
Skip to rigid support emplaced after a delay of several months
Then emplace rigid support sooner after the excavation of the gallery
3- Using parallel drift to compare the different behavior
4- Use mine by experiment (borehole emplaced before the excavation) to study the HM behaviour (at short and long terms)
DRD/MFS/14-0038
AGENCE NATIONALE POUR LA GESTION DES DÉCHETS RADIOACTIFS© Andra© Andra
Meuse/Haute-Marne underground research laboratory
DRD/MFS/14-0038
A huge program of experiments is planned to characterize the response of the rock to different drift construction methods
12 MPa
1,3 h
h
Anisotropic in situ stress field
• 1.3km of drifts• 573 boreholes• 7 300 m of cores• Data acquisition : 7 000
sensor measurements
AGENCE NATIONALE POUR LA GESTION DES DÉCHETS RADIOACTIFS© Andra© Andra
Excavation methods
Test different excavations and supports in parallel drifts to better understand the behavior of the drift by comparison (from low support to stiff support like concrete segments)
DRD/MFS/14-0038
Road header
Pneumatic hammerRoad header under shield
AGENCE NATIONALE POUR LA GESTION DES DÉCHETS RADIOACTIFS© Andra© Andra
Different drift supports (1/2)
DRD/MFS/14-0038
radial rockbolts (3 m long),18 cm of fiber reinforced shotcrete,12 yieldable concrete wedges (hiDcon®)
GCS drift
GCS drift + 27 cm of concretecasted in place 6.5 month afterexcavation
GCR driftradial rockbolts (3 m long),45 cm of fiber reinforced shotcreteemplaced in four layer
BPE drift
AGENCE NATIONALE POUR LA GESTION DES DÉCHETS RADIOACTIFS© Andra© Andra
Different drift supports (2/2)
Segment emplacement methodSegment of 45 cm thickGap filling with radial injection of mortar
DRD/MFS/14-0038
Classical mortarCompressible mortar
with polystyrene ball
AGENCE NATIONALE POUR LA GESTION DES DÉCHETS RADIOACTIFS© Andra© Andra
Mine by experiment
Experimental set up: “Mine by experiment” Boreholes (Displacement, pore pressure) emplaced before excavationConvergence measurements, geological survey, boreholes (displacement)Borehole to characterize EDZ (permeability measurements, velocity survey,
DRD/MFS/14-0038
Around GCSAround GCR
AGENCE NATIONALE POUR LA GESTION DES DÉCHETS RADIOACTIFS© Andra
Some example of results on drifts:
Excavation induced fracture
HM behaviour of drift
DRD/MFS/14-0038
AGENCE NATIONALE POUR LA GESTION DES DÉCHETS RADIOACTIFS© Andra© Andra
Geological survey
DRD/MFS/14-0038
Fracture supérieure du chevron -Shear
Fractures du bombement - extensionFracture inférieure du chevron - Shear
Ecaillage concave (Eco) - ShearFCh/ECo - Shear
Drift // H Drift // h
3D scan is performed to map the front face and analyze fracture orientation (GEOTER)
Fractures types are the same in the two directions but number location and extent differ
AGENCE NATIONALE POUR LA GESTION DES DÉCHETS RADIOACTIFS© Andra© Andra
Induced fracture in drift parallel to H
Structural analysis in an area with numbers of borehole exhibits :
Complex pattern
Extent of shear fracture is larger than tensile fracture
Deep in the rock the shear fracture are visible on different borehole
DRD/MFS/14-0038
AGENCE NATIONALE POUR LA GESTION DES DÉCHETS RADIOACTIFS© Andra© Andra
Induced fractures network
Type of fracture are similar but the extend depend of dirft orientation versus in situ stress state
DRD/MFS/14-0038
Drift Orientation
Extensional fractures extent
Shear fractures extent
Min. Average
Max. Min. Average
Max.
N65// h
Ceiling0.2×D
0.3×D
0.4×D 0.5×D 0.6×D0.8×D
Wall0.1×D
0.1×D
0.2×D - - -
Floor0.2×D
0.4×D
0.5×D 0.8×D0.8 ×D
1.1×D
N155// H
Ceiling-
0.1×D
0.15×D
- - -
Wall 0.01×D
0.2×D
0.4×D 0.7×D 0.8×D1.0×D
Floor-
0.1×D
0.15×D
- - -
G. Armand, F. Leveau, C. Nussbaum, R. de La Vaissiere, A. Noiret, D. Jaeggi, P. Landrein, C. Righini, 2014, Geometry and Properties of the Excavation-Induced Fractures at the Meuse/Haute-Marne URL Drifts, Rock mechanic and Rock engineering, Volume 47, Issue 1, pp 21-41
AGENCE NATIONALE POUR LA GESTION DES DÉCHETS RADIOACTIFS© Andra© Andra
Convergence for drift //
DRD/MFS/14-0038
Drift GCS (// to to H)
Horizontal convergence is higher the vertical one (ratio of 2,1)Velocity decrease as a function of timeNo significant difference between excavated with pneumatic hammer and road header
Deformation rates
AGENCE NATIONALE POUR LA GESTION DES DÉCHETS RADIOACTIFS© Andra© Andra
Convergence for drift // h
Drift GED // to to h
DRD/MFS/14-0038
• Horizontal convergence is higher the vertical one (ratio of Cv/Ch = 4 to 5 )
• Velocity decrease as a function of time• After 1 year , rates <10-10 s-1 Deformation rates
Convergence depends of the drift orientationHighest convergence is observed where the extend of induced fractures is larger
AGENCE NATIONALE POUR LA GESTION DES DÉCHETS RADIOACTIFS© Andra© Andra
Location of the boreholes network
DRD/MFS/14-0038
5
0
5
10
15
20
25
30
35
40
45
50
55
0 5 10 15 20 25 30 35 40 45 50 55 60 65
ylocal[m]
x local [m]
15
10
5
0
5
10
15
5 0 5 10 15 20 25 30 35 40 45 50 55
zlocal[m]
y local [m]
OHZ1111 OHZ1122 OHZ1123 OHZ1501 OHZ1502OHZ1511 OHZ1512 OHZ1521 OHZ1522 OHZ1523OHZ1524 OHZ1525 OHZ1526 OHZ1701 OHZ1702OHZ1703 OHZ1704 OHZ1705 OHZ1707
19 boreholes (mine by test et SMR)
• 8 extensometers
• 3 inclinometers
• 8 multipacker systems
AGENCE NATIONALE POUR LA GESTION DES DÉCHETS RADIOACTIFS© Andra© Andra
Steps of excavation are visible:
2 spans ahead the front, around 2.4 m7 spans beyond the front face, around 8.4 m. At this distance, the long-term behavior is predominant on the instantaneous strain
DRD/MFS/14-0038
Horizontal radial displacement
Extensometer drilled horizontal from the GAT to the GCS and the last anchor (01) is nearly at the sidewall of the GCS
dis
pla
cem
ent
(mm
)
AGENCE NATIONALE POUR LA GESTION DES DÉCHETS RADIOACTIFS© Andra© Andra
Horizontal radial displacement
Radial deformation measured in drift GCS has been reanalyzed in order to separate instantaneous and differed response to digging.
DRD/MFS/14-0038
Elastoplastic deformation represents 40%–45% of the total deformation at 90 days, and around 30% at 900 days. Farther 5.8 m deep in the rock, differed deformation is very small. The contribution of the far field is about 5% of the total elastoplasticdeformation, 4% of the differed deformation at 90 days and less than 1% at 900 days. the very small contribution of the far field to the total deformation at the
wall exhibits that the differed deformation comes from the near field
AGENCE NATIONALE POUR LA GESTION DES DÉCHETS RADIOACTIFS© Andra© Andra
The distance of influence of the excavation is estimated at 20 m
Overpressure of several MPa (3 MPa in chambers 4 at 4.8 m from the GCS wall)
Drop of pressure at the front crossing
DRD/MFS/14-0038
Pore pressure response (horizontal)
Multipacker system located oblique horizontal from the GAT to the GCS
0
10
20
30
40
50
60
70
80
01/04/10
01/05/10
31/05/10
30/06/10
30/07/10
29/08/10
28/09/10
28/10/10
27/11/10
porepressure(bars)
OHZ1521_PRE_01at 37,9m(d= 2,4m/PM35,7)OHZ1521_PRE_02at 33,7m(d=1,1m/PM33,5)OHZ1521_PRE_03at 32,7m(d=1,9m/PM33,0)OHZ1521_PRE_04at 29,3m(d=4,8m/PM31,3)OHZ1521_PRE_05at 23,4m(d=9,9m/PM28,3)PM
First chamber was destroyed during GCS excavation
side view top view0
10
20
30
40
50
60
70
80
08/06/2010
15/06/2010
22/06/2010
29/06/2010
06/07/2010
13/07/2010
20/07/2010
27/07/2010
03/08/2010
10/08/2010
Pressio
n(bars)
AGENCE NATIONALE POUR LA GESTION DES DÉCHETS RADIOACTIFS© Andra© Andra
Lower overpressures in the vertical direction (1order of magnitude difference with the horizontal plane)Drop of pressure is observed near the front face and stabilization as a function of the pore pressure gradientDespite the initial stress state is nearly isotropic around the GCS drift, the pore pressure response is anisotropic
DRD/MFS/14-0038
Pore pressure response (vertical)
Multipacker system located oblique and rising from the GAT to the GCS
0
10
20
30
40
50
60
70
80
01/04/10
01/05/10
31/05/10
30/06/10
30/07/10
29/08/10
28/09/10
28/10/10
27/11/10
porepressure(bars)
OHZ1522_PRE_01at45,6m(d=6,9m/PM37,8)OHZ1522_PRE_02at41,6m(d=4,5m/PM35,8)OHZ1522_PRE_03at38,7m(d=3,5m/PM34,4)OHZ1522_PRE_04at35,7m(d=3,5m/PM32,9)OHZ1522_PRE_05at31,71m(d=4,9m/PM30,9)PM
side view top view0
10
20
30
40
50
60
15/06/2010
22/06/2010
29/06/2010
06/07/2010
13/07/2010
20/07/2010
27/07/2010
03/08/2010
10/08/2010
17/08/2010
Pressio
n(bars)
AGENCE NATIONALE POUR LA GESTION DES DÉCHETS RADIOACTIFS© Andra
HL-LL waste disposal cells
Micro tunnel of 70 cm in diameter
DRD/MFS/14-0038
AGENCE NATIONALE POUR LA GESTION DES DÉCHETS RADIOACTIFS© Andra© Andra
Step by step approach with demonstration and scientific objectives
test the making up of the cell (head & usable part)Study the behaviour of the cell under isothermal conditiontest the making up of different equipments into the cell (base plate, shield steel plug and closing plate),verify the suitable working of the head insert to absorb the thermal dilation of the sleeve,provide data on the casing behaviour under thermal loading,verify the design of the cell head to limit thermal gradients on the drift wall,study the THM behaviour of the interface between rock and casing and of the surrounding rock.
CAC and TEC experiment :smaller scale experiment on steel casing in boreholes
DRD/MFS/14-0038
AGENCE NATIONALE POUR LA GESTION DES DÉCHETS RADIOACTIFS© Andra© AndraDRD/MFS/14-0038
Andra concept for HL-LL waste disposal cells
Horizontal micro tunnels, about 700 mm in diameter and 100m long, cased with steel sleeves
Usable part used for containers disposal,
Head part (“insert”) 10 m long used for cell sealing
End steel plug (base plate), shield steel plug and closing plate
Laser guided auger drilling machine
Casing pushed in place during drilling by 2 m long elements welded or socketed to each others
Retraction of the machine after excavation
Demonstration program in the URL to test the feasibility of construction and the behaviour of such disposal cells
AGENCE NATIONALE POUR LA GESTION DES DÉCHETS RADIOACTIFS© Andra© Andra
ALC experiment
)) Phase 1 (2009): cell of 20 m length
)) Phase 1 bis (2010): cell of 40 m length
)) Phase 2 (2011): cell of 40 m length withsensors on the sleeve
Insert of 7 m to test emplacement of thehead
)) Phase3.1 (2012): cell of 100 m length
DRD/MFS/14-0038
AGENCE NATIONALE POUR LA GESTION DES DÉCHETS RADIOACTIFS© Andra© Andra
HLW disposal cells
)) Phase 3.2 (2012/2013):
EDZ
Heating dummy packages empty insert
Closed fractures
Delayed phase: closure plugging
Initial phase: easily retrieviable package stage
• Full-sized reproduction of a HLW cell(WP3 of EC project LUCOEX) => THMbehavior
Main objectives :• Test the making up• Verify the design of the cell head to absorb
the thermal dilation of the casing and to limit thermal gradients on the drift wall.
DRD/MFS/14-0038
AGENCE NATIONALE POUR LA GESTION DES DÉCHETS RADIOACTIFS© Andra© Andra
Excavation induced fractures around micro tunnel
DRD/MFS/14-0038
Similar shape of fracture pattern at different size (// H)
HA vault
Fractures model around driftRock bolt
AGENCE NATIONALE POUR LA GESTION DES DÉCHETS RADIOACTIFS© Andra© Andra
HA cell // to H (CAC1601)
Relative humidity in the void Convergence of casing
60
65
70
75
80
85
90
95
100
0 50 100 150 200 250 300 350
Humidité
Relativ
e(%
)
jours
HR à 35 mHR à 25 mHR à 15 mHR à 7 m
Objective (Phase 2)Behavior of the void : water arrival versus time dependant behaviour and closure of the void
Loading of the steel casing
Test of optical fibers method
HM behaviour of the micro tunnel
3
2
1
0
1
2
3
0 50 100 150 200 250 300 350
Convergence(m
m)
days
vertical / 35 m deephorizontal / 35 m deepvertical / 25 m deephorizontal / 25 m deepvertical / 15 m deephorizontal / 15 m deep
DRD/MFS/14-0038
AGENCE NATIONALE POUR LA GESTION DES DÉCHETS RADIOACTIFS© Andra© Andra
P
v
h
t < 60 daysLoading localized in the horizontal direction
60 days < t < 160 daysanisotropic loading
h > v
t > 160 daysDecrease of anisotropic loading
v
h
75
15+
Expriment in borehole with steel casing (1/2)
o steel N80 ( y = 550 MPa)
o Borehole : Ø = 146 mm
o casing : Øout = 143 mm, thickness = 4,5 mm
DRD/MFS/14-0038
AGENCE NATIONALE POUR LA GESTION DES DÉCHETS RADIOACTIFS© Andra© Andra
5 - 15°
CAC1001 : /e 32
CAC1002 : /e 32
CAC1003 : /e 47
Orthoradial deformation at 8 m deep in borehole
400
300
200
100
0
100
200
300
400
0 50 100 150 200
(MPa)
days
CAC1001 (e=4,5mm)CAC1002 (e=4,5mm)CAC1003 (e=3 mm)
y = 550 MPa
Expriment in borehole with steel casing (2/2)
DRD/MFS/14-0038
Remain in elastic domain, no problem of stability of the casingBut it will contribute to corrosion under stress which is a difficulty for the design of the casing
AGENCE NATIONALE POUR LA GESTION DES DÉCHETS RADIOACTIFS© Andra© Andra
HL-LL waste disposal cells
The experiment performed at the URL serve to optimize the concept
In 2009 the reference length in the concept was 40 m and all cell are parallel to H
It was demonstrate that a longer depth could be reached= now reference length = 80 m
It was confirmed that excavation of cell along H is better than h
Elastic deformation in traction have been observed (due to the difference of convergence rate in horizontal and vertical direction) and will contribute to corrosion under stress
Backfill the void in between the casing and rock (concrete with bentonite)A test has been performed in November 2013
DRD/MFS/14-0038
AGENCE NATIONALE POUR LA GESTION DES DÉCHETS RADIOACTIFS© Andra© Andra
Summary (1/2)
Experiments in the MHM URL serve to Demonstrate feasibility of a deep geological repository and upscale data obtained on sample (diffusion/retention, permeability,…) Demonstrate the working of the different conceptOptimize the different conceptsData based to develop/validate model
But you also needFundamental research to assess the physical process in order to develop model to extrapolate data to the lifetime of a repository
Safety calculation to always check if optimization do not decrease the safety At the beginning of the repository construction, final design will be tested in the repository to check in the repository conditions if predicted behavior is observed.
DRD/MFS/14-0038
AGENCE NATIONALE POUR LA GESTION DES DÉCHETS RADIOACTIFS© Andra© Andra
Summary (2/2)
Behavior of the driftTwo major phenomena can be distinguished :
Elastoplastic and damage mechanisms seems to be predominant at short termsDrift ‘s deformations develop as a function of time
During excavation work, fractures network are induced (mainly shear fracture 75%, extensional fracture 25%)The extend of the fracture network depend on the drift orientation versus the in situ stress field and could not be explain by the anisotropy of the stress field
No impact of the method of excavation (BRH versus MAP)Shear fractures (deep in the rock) exhibit low transmissivityWith water uptake, fractures transmissivity decreases drastically
Anisotropic convergence of the drift are observed :anisotropy of convergence develops in two opposite directions in drifts parallel and perpendicular to H major convergence is measured where the fracture zone is located
Differed deformations After one year, deformation rates are in the same velocity range than the one measured on creep test or lower.Most of the differed deformation appears in the fractured zone
DRD/MFS/14-0038
AGENCE NATIONALE POUR LA GESTION DES DÉCHETS RADIOACTIFS© Andra
Thank you for your attention
Danke Ihnen für Ihre Aufmerksamkeit
Merci pour votre attention
DRD/MFS/14-0038
G. Armand, F. Leveau, C. Nussbaum, R. de La Vaissiere, A. Noiret, D. Jaeggi, P. Landrein, C. Righini, 2014, Geometry and Properties of the Excavation-Induced Fractures at the Meuse/Haute-Marne URL Drifts, Rock mechanic and Rock engineering, Volume 47, Issue 1, pp 21-41
G. Armand, A. Noiret, J. Zghondi, D.M. Seyedi,2013, Short- and long-term behaviors of drifts in the Callovo-Oxfordian claystone at the Meuse/Haute-Marne Underground Research Laboratory, Journal of Rock Mechanics and Geotechnical Engineering 5,pp 221–230