Géotechnique des ouvrages souterrains comportements

Géotechnique
Géotechnique des
des ouvrages
ouvrages souterrains
souterrains
comportements
comportements post
post rupture
rupture
Thierry YOU,
CFMR/AFTES 2006
Géotechnique des ouvrages
souterrains
comportements post rupture
Laboratoire
Retours d’expérience
Conclusions
CFMR/AFTES 2006
Augmentation contrainte axiale
D’après Lockner et al. Observations of quasi-Static fault growth from acoustic emissions,
in Fault Mechanics and Transport Properties of Rocks, B. Evans and T.-F. Wong ed., 1992
ESSAI TRIAXIAL LABO SUR ECHANTILLON MARNE
Vitesse de déformation = 2.10-6 s-1
Pression de confinement = 4 MPa
50
45
Contrainte Axiale MPa
40
35
E = 10.1 GPa
30
25
E = 9.3 GPa
20
E = 4.9 GPa
15
10
E = 7.7 GPa
5
0
0
0.005
0.01
0.015
Déformation Axiale
0.02
0.025
SYDNEY
ROCK FALL EXPLANATIONS (20+)
• A large number of explanations were put forward by the parties
involved, many of them with ulterior motives: unsuitable section,
inappropriate and damaging explosive, poor workmanship
(drilling, bolting, etc.), untested rock bolts, too differed bolt
grouting, poor site organisation, unsuitable numerical and
structural models, underdesigned rockbolts, inappropriate bolting
patterns, unsuitable excavation sequence, poor and inefficient
quality control, lack of design methodology (EC7), lack of
monitoring and inspection, unforeseen stress release, random
vertical joints, lack of spot bolt decision on visible instabilities,
inclined defects in sheet facies, too high water pressure imposed
in the fissures, etc.
• At that stage, none of the specified monitoring measures that had
been prepared for design validation (geological joint mapping,
convergence measurement, profile mapping, pull-out test, etc.),
that certainly would have helped as new design basic data, had
been implemented.
• Maintaining roof integrity was crucial for stability, as was
established latter
(You et al. Johannesburg ISRM2003)
SYDNEY - UDEC
DESIGN METHODOLOGY FOR
HYDROCARBON CAVERNS
INFLUENCE OF IN-SITU STRESSES ON LARGE SECTIONS
Top heading and bench 1
INFLUENCE OF IN-SITU STRESSES ON
LARGE SECTIONS
VISAKHAPATNAM
BED egg-shape cross-section
Revised basket-handle cross-section
ARMS,4 - 2006 Singapore
UNDERGROUND STORAGE IN MINED
CAVERN
PRINCIPLES
Stability
Operation
Hydrodynamic
Containment
Neither a Mine, neither a Civil Construction, neither a Laboratory
ARMS,4 - 2006 Singapore
INFLUENCE OF IN-SITU STRESSES ON
LARGE SECTIONS
Basic parameters and model geometry used for the numerical analysis
m id -p illa r
g ro u n d le ve l (y = 0 m )
d o m ain fo r fin e r m e s h in g
h o rizo n ta l fra c tu re
c a ve r n
ARMS,4 - 2006 Singapore
Joint aperture for the rounded shape after product filling
ARMS,4 - 2006 Singapore
32
33
34
35
36
37
Géotechnique des ouvrages
souterrains
comportements post rupture
PREMIÈRES CONCLUSIONS
Le concept est encore un objet de recherche
La définition des modes de rupture n’est pas
toujours aisée
Le phénomène peut aussi être relatif.
CFMR/AFTES 2006