Presentazione di PowerPoint

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• General meeting LAGUNA
• LAGUNA Fréjus site
• Geotechnical feasability
• (Rewiew of WP2 Munich January 26th-27th, 2009)
• March 30th.- April 2nd 2009, Wroclaw

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CURRENT SITUATION GENERAL PLAN
LSM Underground Laboratory Modane
Road tunnel
Railway tunnel
Longitudinal section
gt1500 m rock overburden
6,2 km
6,6 km
12.8 km
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Geotechnical parameters of rock mass

• Unit weight 27 kN/m3
• Elastic modulus 15 GPa
• Poissons ratio 0.2
• Friction angle 35/40 (lower/mean value)
• Peak cohesion 3000 kPa
• Residual cohesion 2000 kPa (short term)
  500-750 kPa (medium term) 200-300
  kPa (long term)
• Plastic strain 0.5 (for reach residual
  cohesion)
• Dilation angle 3

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Main characteristics of calc-schists

• Time-dependent behaviour of rock mass
  (displacements)
• Tendency to wedge instability on roof
• Anisotropy of rock mass properties (effect of
  schistosity)
• Reduction of rock mass strength after failure
• No water circulation in the rock mass (OK for
  cavern stability
• and thermal losses during reservoir operation)

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Cavern design
LENA 221'000 m3
GLACIER 320'000 m3
MEMPHYS 558'000 m3
9 m
17 m
21.9
41.9
19 m
47.5
110 m
70 m
D76 m
D67 m
25 m
D35 m
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Memphys 3D model (FLAC)
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Memphys Displacements Long term
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Memphys Failure zone Long term
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Memphys Analysis of wedge stability
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Large excavations at Frejus - Conclusions

• The construction of the large excavations for
  the 3 detector types of Laguna is feasible at
  Frejus site.
• For Glacier it is possible to built a unique
  large tank. The division into
• 2 smaller tanks can reduce the total
  construction costs of the caverns.
• For Lena it is not necessary to have curved
  walls
• The final lining should be placed at least 2-3
  months after the excavation
• in order to reduce the rock pressure in the
  long term (excavation from
• top to bottom, construction of final lining
  from bottom to top).

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Interaction between tank and rock mass

• The stability of the rock mass during excavation
  is ensured by anchors and reinforced shotcrete
• The definitive cavern is sustained by a concrete
  lining.
• Glacier needs a inner, independent tank.
• The rock loads are supported by the concrete
  lining and will not be
• transferred on the steel tank.
• The water from the rock mass can cause an
  external load on the
• imperious tank (even if apparently the rock
  appears dry). To avoid this
• type of load, it is necessary to design an
  external drainage system.
• The earthquake is not a problem for the steel
  tank, if there is not an
• active fault crossing the cavern (atypical
  situation).

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Location LAGUNA
Safety tunnel
Road tunnel
LAGUNA
Railway tunnel
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LAYOUT (top view)
Access Tunnel
Control room, offices, storage, power
Safety Tunnel
Electronics
Air and water purification
Electronics
Road Tunnel
Electronics
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LAYOUT (side view)
Air and water purification

• Safety Tunnel

Road Tunnel
Electronics
Electronics
Control room, offices, storage, power
Access Tunnel
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LAYOUT
Access Tunnel
Safety Tunnel
Electronics
Air and water purification
Storage
Control room
Offices
Power
Electronics
Cables, piping etc
Electronics