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Design of LargeDesign of Large--sized sized Accelerator TunnelAccelerator Tunnel

SpeakerSpeaker

Takashi Kato, Nikken Sekkei Ltd.,Takashi Kato, Nikken Sekkei Ltd.,

AkinoriAkinori Tamura, Nikken Tamura, Nikken SekkeiSekkei Civil Ltd.Civil Ltd.

2007.6.28

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SPring8, XSPring8, X--FELFEL

33

JJ--PARCPARC

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GHMCGHMC

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ILCILC

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IntroductionIntroduction

Accelerator Facilities / Civil EngineeringAccelerator Facilities / Civil EngineeringKKey points ey points for thefor the design of underground design of underground accelerator tunnel accelerator tunnel Overview of the sOverview of the structural analysis tructural analysis concerning with necessity of Expansion Jointsconcerning with necessity of Expansion Joints

Based on the experience in Based on the experience in JJ--PARCPARC

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2 key2 key--points for the designpoints for the designof undergroundof underground accelerator tunnelsaccelerator tunnels

①① Transformation of the accelerator tunnel Transformation of the accelerator tunnel should be minimalshould be minimal

②② Level of integrity and durability of the tunnel Level of integrity and durability of the tunnel structure should be highstructure should be high

→→ ◆◆stable operation of the acceleratorstable operation of the accelerator

→→ ◆◆very few cracks in the cover concretevery few cracks in the cover concrete

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①①Transformation of the tunnel Transformation of the tunnel is controlled by following factorsis controlled by following factors

Geological features, Situation of groundwaterGeological features, Situation of groundwaterChange of live load to the tunnelChange of live load to the tunnelTemperature change inside the tunnel, Temperature change inside the tunnel, Influence from earthquakeInfluence from earthquakeStructure of the tunnel itselfStructure of the tunnel itself

(Foundation, (Foundation, Expansion jointExpansion joint,, etc.)etc.)

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②② Integrity and durability of the tunnel Integrity and durability of the tunnel is controlled by following factorsis controlled by following factors

＝＝To realize very few cracks in tunnel concreteTo realize very few cracks in tunnel concreteTo use watertight mass concreteTo use watertight mass concreteTo place indispensable quantity of reinforcement To place indispensable quantity of reinforcement accurately in positionaccurately in positionTo perform proper waterproofing workTo perform proper waterproofing workTo take appropriate measures against shrinkage To take appropriate measures against shrinkage of concreteof concreteStructure of the tunnel itself Structure of the tunnel itself (Foundation, (Foundation, Expansion jointExpansion joint,, etc.)etc.)

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JJ--PARC 50GeVPARC 50GeV synchrotron tunnelsynchrotron tunnel

Bird's-eye view of J-PARC 50GeV

Complicated layer

Cross-section of J-PARC 50GeV tunnel

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-300

-200

-100

0

100

200

300

-300 -200 -100 0 100 200 300

Without Expansion joint If provided Expansion Joints

-300

-200

-100

0

100

200

300

-300 -200 -100 0 100 200 300

Analysis model

Expansion JointsExpansion Joints

Expansion joint

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Tem perature of concrete（15℃air supply)

0.00

5.00

10.00

15.00

20.00

25.00

30.00

1 58 115 172 229 286 343 400 457 514 571 628 685 742

Passing tim e（ｈour）

Temperature（℃）

Shut-down (winter)

Condition of structural analysisCondition of structural analysis

(T(Temperature change of tunnel concrete emperature change of tunnel concrete ))

Structural analysis was performed based on the assumption Structural analysis was performed based on the assumption of safe side that the temperature of tunnel concrete change of safe side that the temperature of tunnel concrete change 1212℃℃

12℃

Operation

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Axial force diagram in the case of concrete temperature 1℃ rises

Software of structural analysis3-dimensional ground and structure seismic response analysis system DINAS

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Bending Moment diagram in the case of concrete temperature 1℃ rises

(12℃ changes)

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Maximum displacement to outside direction of the ring tunnel in a curved part is around 4mm

Lap length of the ring tunnel increases around 3mm

Transformation diagram in the case of concrete temperature 1℃ rises

average expansion and contraction rate 1.6×10-7（1/℃）＜linear thermal expansion rate of concrete 1.0×10-5（1/℃）

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SummarySummary

KKey points ey points for thefor the design of the underground design of the underground accelerator tunnelaccelerator tunnel

→→ Transformation should be minimal and level of integrity Transformation should be minimal and level of integrity and durability of the tunnel structure should be highand durability of the tunnel structure should be high

SStructural analysis concerning with necessity of tructural analysis concerning with necessity of Expansion JointsExpansion Joints

→→ TThere will be no incidence of displacement and cracks here will be no incidence of displacement and cracks in the tunnel concrete without expansion jointsin the tunnel concrete without expansion joints

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Thank you very much for your attentionThank you very much for your attention