A51 : MONESTIER DE CLERMONT VIADUCT
FOUNDATIONS OF MONESTIER VIADUCT • • •
Dominique Quivy Laurent Bastard-Rosset Michel Londez
VINCI Construction France GTM TP Lyon Independent expert Mécasol
MONESTIER DE CLERMONT VIADUCT
MONESTIER DE CLERMONT VIADUCT
PARTNERS
Contracting Authority
Les Autoroutes Rhône-Alpes
Design and built joint
GTM TP Lyon, mandatary
venture
Geotechnical engineering
MECASOL
Civil engineering design office
VINCI Construction B.E.T.
Architect : Jean-Vincent
STRATES
Berlottier
PAYSAGE PLUS
Landscape painter
BAUDIN-CHATEAUNEUF
Structural steel Construction MONESTIER DE CLERMONT VIADUCT
PLANNING
MONESTIER DE CLERMONT VIADUCT
MONESTIER DE CLERMONT VIADUCT
MONESTIER DE CLERMONT VIADUCT
GEOTECHNICAL ENVIRONMENT Michel LONDEZ
MONESTIER DE CLERMONT VIADUCT
Chemin de fer
Geological Cross section
Rock
Moraines
P5
P6
grey clay
Rock Varved clay
vvy
Moraines Rock Clay and blocks
Sliding Area
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Chemin de fer
PIERS SETTING OUT
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SLIDING ZONE
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P3 & P4 FOUNDATIONS CONSTRUCTION Laurent BASTARD-ROSSET
MONESTIER DE CLERMONT VIADUCT
FOUNDATIONS Five different types of foundations : C0 & P1 : Large pits (4 m diameter) P2 : Concrete piles (1,5 m diameter) P3 & P4 : semi-deep Foundations
C0
P1
P2
P3
P4
P5 & P6 : Piles inside circular diaphragm wall P7, P8 & C9 : Spread footing
P5
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P6
P7
P8
C9
P3 & P4 FOUNDATIONS
P3
Bellow P3 and P4, varved clay which is water saturated, is present up to 80m deep. Ground is therefore not stiff enough to carry heavy loads. The design of the foundations is quite unusual : the principle consists in taking off a quantity of clay equivalent to the load brought by the pier itself (weights of the foundation + pier + deck ).
MONESTIER DE CLERMONT VIADUCT
P3 & P4 FOUNDATIONS
raft
22 m 20 m
Steel inclusions
diaphragm wall
P3 FOUNDATION INCLUDES : - a diaphragm wall (20m diameter and 22m deep). - 20m long steel profiles (HEA 300) driven into clay - a 1,50m thick concrete slab, poured above a 1,00m thick gravel layer. - 80cm thick concrete walls stiffening the structure and allowing transfer of pier load to the diaphragm wall and concrete slab. - The inside volume (1700m3) remains empty except during construction of the pier when it is filled with water.
MONESTIER DE CLERMONT VIADUCT
P3 & P4 : DIAPHRAGM WALLS GROUND EXTRACTION
MONESTIER DE CLERMONT VIADUCT
P3 & P4 : DIAPHRAGM WALLS GROUND EXTRACTION
MONESTIER DE CLERMONT VIADUCT
P3 & P4 : DIAPHRAGM WALLS REINFORCEMENT AND CONCRETE
MONESTIER DE CLERMONT VIADUCT
P3 & P4 : STEEL PROFILES DRIVEN INTO CLAY (STAGE 1)
MONESTIER DE CLERMONT VIADUCT
P3 & P4 : CLAY EXCAVATION INSIDE DIAPHRAGM WALLS
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P3 & P4 : FINAL PREPARATION FINAL PREPARATION OF THE GROUND BEFORE GRAVEL LAYING OPERATIONS AND CUTTING BACK OF STEEL PROFILES
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P3 & P4 : STATE OF THE FOUNDATION JUST BEFORE GRAVEL IS LAY DOWN
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P3 & P4 : GRAVEL LAYER AND PIEZOMETER IN PLACE
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P3 & P4 : REINFORCEMENT OF CONCRETE SLAS
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P3 & P4 : STIFFENING STRUCTURE WALLS
MONESTIER DE CLERMONT VIADUCT
P3 & P4 : GENERAL VIEW
MONESTIER DE CLERMONT VIADUCT
SETTLEMENTS CALCULATIONS Michel LONDEZ P3CPT3 -20.000
0.000
20.000
40.000
Cu (kPa)
0 0
50
100
150
200
0.000
- 10
-20.000
P ro f o n d e u r (m )
- 20
- 30
-40.000
- 40
- 50 -60.000
- 60
C (qt/12)
C (qt/10)
Pressiomètre P3S2
¨Pile 3 - Radier à -7m/TN Point sur la paroi
50 Consolidation
Numéro des pas de calcul
40
Mise en place de la charge de service
Ouvrage terminé Vidange de la fouille effectuée 30 Radier Relachemenent nappe 20 Avant clavage+ remplissage
Fin de mise en place du gravier
10
Fin d 'excavation 0 -0,09
-0,07
-0,05
-0,03
-0,01
0,01
Tassements de la paroi (m) P3C1CasA
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P3C1CasB
P3C1CasC
0,03
0,05
THE STUDIES Survey program
P3 to P6 Core borings, CPTU 65 m deep Pressiometric tests Cross hole Pumping test Inclinometres Laboratory tests
MONESTIER DE CLERMONT VIADUCT
MAIN RESULTS
Accross the valley:
South west area: - Rock at 50 m. - Fluvio-glacial permeable till between 40 à 50 m - Gravelly clays below soft and remolded clays
Centre and north of the valley: - Deepening of rock (P2) - Argiles homogeneous clays at the surface, varved below
MONESTIER DE CLERMONT VIADUCT
GEOLOGICAL PROFILE
Chemin de fer
Geological Cross section
Rock Moraines
grey clay
Clay and blocks
varved clay Varved stiffer clay Rock
ClSliding Areay and blocks MONESTIER DE CLERMONT VIADUCT
Rock Rock
PENETRATION TEST FOR P3
MONESTIER DE CLERMONT VIADUCT
CU (KPA) FROM CPTU AND PRESSURMETRES P3CPT3 Cu (kPa)
0 0
50
100
150
- 10
P ro f o n d e u r (m )
- 20
- 30
- 40
- 50
- 60
C (qt/12)
C (qt/10)
Pressiomètre P3S2
MONESTIER DE CLERMONT VIADUCT
200
OCR FOR P3 P3CPT3
1
1,5
2
0
- 10
- 20
- 30
- 40
- 50
- 60
MONESTIER DE CLERMONT VIADUCT
2,5
OCR
3
FOUNDATION OF BEARINGS P3 & P4
The foundations of P3 and P4 include : - a cylindral skirt made of diaphragm wall, 20m diameter and 22 to 26 m deep. - A 1,50m thick concrete slab - Steel inclusions (HEA 300), down to 20m below the slab, - Stiffening walls 80cm thick to tranfert the shaft efforts to the slab and the diaphragm walls An inner volume of 1700m3 above the slab remains empty.
MONESTIER DE CLERMONT VIADUCT
Steel profiles setting out
MONESTIER DE CLERMONT VIADUCT
PARAMETRES OF CALCULATIONS
Strength C’ (KN/M2)
φ’(°)
OCR
Depth (m)
Type of soil
18.5
5
24
σ’0+50 KN/M2
0 - 18
Upper clay
18.5
0
24
σ’0
18 – 37/55
Medium clay
18.5
10
30
37/55 80
Lower clay
Volumetric mass(KN/M3)
1.2 σ’0
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PARAMETRES OF CALCULATIONS
Deformation CASE A
CASE B
CASE C
Triaxial Interpretation
Oedometric Interpretation
Oedometric method
Soil
E50réf (kN/m2)
Eoedréf (kN/m2)
E50réf (kN/m2)
Eoedréf (kN/m2)
Cc/1+e
Cg/1+e
7500
6000
3150
2500
0.12
0.024
Upper clay
7500
6000
3150
2500
0.12
0.024
Medium clay
7500
6000
7500
6000
MONESTIER DE CLERMONT VIADUCT
Hardening Model
Lower Clay
CALCULATION MODEL -20.000
0.000
20.000
0.000
-20.000
-40.000
-60.000
MONESTIER DE CLERMONT VIADUCT
40.000
SEQUENCES OF CALCULATIONS
• Excavation of a mass of soil close to the estimated load brought by the pier • Inclusions to control the soil relaxation , reduce the recompression settlement • Maximum loads during construction ( pre-loading with water) • After final bearings installation, settlements calculations under final loads and surcharges, consolidation. • Acceptable differential settlements between piers: 6 cm.
MONESTIER DE CLERMONT VIADUCT
SETTLEMENTS ESTIMATIONS
Design loads Settlements in mm
Calculation Cases
Soil parametres
Raft construction
Loads without Superstructures + water
Total + service loads + Consolidation
P3
P4
P3
P4
P3
P4
A
Triaxial interpretation
5
6
33
35
21
21
B
Triaxial interpretation*0.42
7
6
62
56
50
38
C
Oedometric model
7
7
50
44
30
35
MONESTIER DE CLERMONT VIADUCT
PARAMETRES OF CALCULATIONS
Deformation CASE A
CASE B
CASE C
Triaxial Interpretation
Oedometric Interpretation
Oedometric method
Soil
E50réf (kN/m2)
Eoedréf (kN/m2)
E50réf (kN/m2)
Eoedréf (kN/m2)
Cc/1+e
Cg/1+ e
7500
6000
3150
2500
0.12
0.024
Upper clay
7500
6000
3150
2500
0.12
0.024
Medium clay
7500
6000
7500
6000
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Hardening Model
Lower Clay
OBSERVATIONS DURING CONSTRUCTION
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OBSERVATIONS DURING CONSTRUCTION
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COMMENTS
• For P3, settlements during construction were close or slightly higher than those estimated with the triaxial interpretation (case A) • Needs for setlements reductions have been estimated necessary • Adaptations of the design have been done: - Preload with water, removed when superstructures have been completed. - Deck level set out 20 mm above designed level to increase the acceptable differencial settlements to 80 mm instead of 60 mm initialy considered in the design. • For P4, the setlements are much lower due to the longer length of the diaphragm wall skirt.
MONESTIER DE CLERMONT VIADUCT
SETTLEMENTS VERSUS TIME
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Comparison between estimations and observations Settlements in mm
End of construction
Estimations Observations
In service
P3
P4
P3
P4
33 to 62
37 to 56
21*
21*
11.5**
13.5**
37
19
•* End of consolidation~ 80 years •** After ~4 years: Consolidation not completed • **To be compared to 80 mm acceptable differential settlements
MONESTIER DE CLERMONT VIADUCT
