LE BARRAGE FAIT PEAU NEUVE - barrages-cfbr.eu · LE BARRAGE FAIT PEAU NEUVE THE CRACKS • 1963:...

02 février 2016

LE BARRAGE FAIT

PEAU NEUVE

1 Context

2 Preliminary studies

3 Numerical Modelling

4 Rehabilitation works

CONTEXT

LE BARRAGE FAIT PEAU NEUVE

HISTORY

1947 – 1951 : Building


THE CRACKS

• 1963: The SCP takes possession of

the bimont Dam

• Only 3 years after Malpasset

disaster

• Numerous cracks observed on the

second plot and on the right bank of

the dam

Cote 329,50 m NGF

Cote 329,50 m NGF


THE CRACKS

• The geology was first suspected.

• Numerous fields of investigations:

➢ Complementary geological studies

➢ Gallery cutted into the rock foundation of the second cantilever

➢ Additionnal monitoring instruments: 2 plumblines, fissurometers,

Topographic survey

➢ Mapping of the cracks network

➢ Several numerical models

A geological cause of the damages was rejected

THE CRACKS

16 cm

14 cm

~ 3 cm

PRELIMINARY

STUDIES


PRELIMINARY STUDIES


PRELIMINARY STUDIES

The investigations showed internal cracks into

the seven cantilevers of the rights banks

G

P1 P2 P3 P4 P5

P6 P7

P8 B A

C D E

F

340

330

325

320

310

300

B1 B3

B2 B4

B43

B42

B5

B6

B10

B7

B9

B12

B17

B14

B15

B11

B22

B21

B26

B18

B19

H

Légende :

Droite verticale jaune : limite de plot

Droite horizontale jaune : courbe de niveau

Zone hachurée blanche : zone de gonflement du béton

Zone avec une bordure blanche : zone d’extension probable de la fissure

de feuilletage

Point orange : fissure (cumul <10)

Point rouge gros : fissure (cumul >10)

Point vert : pas de fissure ou microfissure

B16

B13

B20

B24

B25

B8

B51

B27

B28

B29

B31

B30

305

B32


LAST LABORATORY TEST

• Electron microscope, energy dispersive X-ray spectrometer

Presence of massive secondary ettringite resulting from an internal

sulphate reaction.


LAST LABORATORY TEST

• Test performed during

106 weeks to assess the

residual expansion of

concrete samples taken

into sane concrete and

swelling concrete.

NUMERICAL

MODELLING

10 juin 2010

Barrage de Bimont 17G

P

1P

2

P

3

P

4

P

5

P

6

P

7

P

8

BA

C D EF

340

33

0

32

0

31

0

300

H

Zones de

gonflement

TRACTEBEL

10 juin 2010

18

Barrage de BimontG

P

1P

2

P

3

P

4

P

5

P

6

P

7

P

8

BA

C D EF

340

33

0

32

0

31

0

300

H

Zones de

gonflement

TRACTEBEL

10 juin 2010

19

Barrage de BimontG

P

1P

2

P

3

P

4

P

5

P

6

P

7

P

8

BA

C D EF

340

33

0

32

0

31

0

300

H

Réseau de

fissures

visibles

TRACTEBEL

20

Barrage de BimontG

P

1P

2

P

3

P

4

P

5

P

6

P

7

P

8

BA

C D EF

340

33

0

32

0

31

0

300

H

Downstream View:

Swelling zones

Cracks

Open construction joints

DAM AND FOUNDATION MESHES

2

2

•Isotropic thermal equivalence

•SCAS model (Stress Controlled

Anisotropic Swelling) :

tgg

ig Fi

0iF

gLiF

L

i

gLiF

1

with i=1, 2, 3

If i L (high compression),

if i 0 (tension),

si 0 i L

-1

0

1

2

3

4

5

6

0 5 10 15 20

σi

εi (µm/m/an)

SWELLING MODELISATION

23

STRESS CONTROL ANISOTROPIC

SWELLING LAW (SCAS) WITH

σL= 5 MPa, εGL = 90 10-6M/M/Y

εGL varying from1,4 to 2,7 mm/m

Comparaison des Δz crête de nivellement calculés

0.0

5.0

10.0

15.0

20.0

25.0

30.0

35.0

40.0

1 2 3 4 5 6 7Plots

Δz c

rête

(en

mm

)

Auscultation

Gonf 225 105 90 70

σL = 5 MPa ε = 2700

2700 1400 1400

σL = 4 MPa ε = 2700

2700 1400 1400

σL = 4 MPa ε = 2700

1800 1400 1400

σL = 3.5 MPa ε =

3500 3500 1500 1500

Dérives radiales

-35

-30

-25

-20

-15

-10

-5

0

5

0 2 4 6 8 10 12

Plots

Déri

ves (

en

mm

)

Auscultation

Gonf 225 105 90 70

σL = 5 MPa ε = 2700

2700 1400 1400

σL = 4 MPa ε = 2700

2700 1400 1400

σL = 4 MPa ε = 2700

1800 1400 1400

σL = 3.5 MPa ε =

3500 3500 1500 1500

Dérives tangentielles

-25

-20

-15

-10

-5

0

5

10

0 2 4 6 8 10 12

Plots

Dé

riv

es

(e

n m

m)

Auscultation

Gonf 225 105 90 70

σL = 5 MPa ε = 2700

2700 1400 1400

σL = 4 MPa ε = 2700

2700 1400 1400

σL = 4 MPa ε = 2700

1800 1400 1400

σL = 3.5 MPa ε =

3500 3500 1500 1500

SWELLING MODELISATION

Tangential drift Radial drift

Crest elevation drift

Deformations

DAM PRESENT STATE – RWL= 329

Swelling zones

Open joints

25

Without swelling

With swelling

Downstream face / parement aval

Principal stresses / contraintes principales


2

6

Interpretation


Swelling

zones

Joints opening

Internal

crack

Horizontal

crack

Vertical

crack

2

7

Internal cracking surface


As observed

As simulated

REHABILITATION

WORKS

– Cracks grouting

– Construction joints grouting

– Upstream face watertightning

– RB thrust block reinforcement

– Drainage curtain

REHABILITATION PROJECT

Cracks grouting: why ?

Internal

cracks

« half « dam

US – Hydrostatic

pressure

– Avoid application

of pore pressure

on internal cracks

surface

– allow the arch

stresses to be

transmitted in the

dam body

• Identified risks

– Potential extension of cracks under

grouting pressure

– Possibility to eject the concrete part

between the internal crack and dam

faces due to grouting pressure

–

Cracks grouting


• Technical solutions

– Temporary reinforcement with passive

horizontal anchors

– Systematic inspection of all drillings by

camera

– Cement grouting process bottom up

– Grouting pressures carefully monitored en

reduced surfaces (4 x 4 m)

- Automatic topographic surveillance

Cracks grouting


Cracks grouting : passive anchors implementation


Construction joints grouting


US face watertighting


Drainage curtain in the foundation



PLANNING

4 – Reservoir refilling

2016

2017

2019

2017

2019

1 – Water by-pass implementation

Reinforcement of monitoring system

2 – Reservoir emptying

3 – Rehabilitation works

21/11/2017

Les travaux préparatoires : la dérivation

Galerie de la Campane

Branche de Marseille Nord

vidange

Conduite de dérivation

Transit par la retenue

et les vidanges


PHASE 1

3 nouveaux télépendules, inversés

LA RENOVATION DU DISPOSITIF D’AUSCULTATION

5 téléfissuromètres

7 cellules de pression interstitielle


THANK YOU FOR YOUR

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