brito3 presentation

7/18/2019 Brito3 Presentation

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International Seminar on Tunnels and Underground Works

Jos A. Mateus de Brito,[email protected]

Carlos de Oliveira Baio,[email protected]

Antnio C. Ambrsio,[email protected]

TUNNEL DESIGN AND CONSTRUCTION INTUNNEL DESIGN AND CONSTRUCTION INTUNNEL DESIGN AND CONSTRUCTION INTUNNEL DESIGN AND CONSTRUCTION IN

MADEIRA ISLANDMADEIRA ISLANDMADEIRA ISLANDMADEIRA ISLAND

SocorridosSocorridosSocorridosSocorridos pumping station andpumping station andpumping station andpumping station and

water storage tunnelwater storage tunnelwater storage tunnelwater storage tunnel


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MADEIRA ISLAND


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(5,5m wide)(7m wide)

Pumping station

Hydroelectric plant

Stream

Access tunnelStorage tunnel


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Sediment

evacuation channel Main channel

Penstock

Hydroelectric plant

Access tunnel

Pumping station

Storage tunnel

Stream


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12,5 m

26,5

mAccesstunnel

Pumpingstation

Storagetunnel

Temporaryrockfill

Mainchannel

Sedimentevacuation channel

4 pumps (16 mhigh): 40.000 m3

raised in 6h by the

existing penstock

(460m)

Sediment traps

Existingpenstock


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Jul.05


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GEOLOGICAL AND GEOTECHNICALGEOLOGICAL AND GEOTECHNICALGEOLOGICAL AND GEOTECHNICALGEOLOGICAL AND GEOTECHNICAL

CHARACTERISTICSCHARACTERISTICSCHARACTERISTICSCHARACTERISTICS

GEOLOGICAL AND GEOTECHNICALGEOLOGICAL AND GEOTECHNICALGEOLOGICAL AND GEOTECHNICALGEOLOGICAL AND GEOTECHNICAL

CHARACTERISTICSCHARACTERISTICSCHARACTERISTICSCHARACTERISTICS


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Consolidated alluvia

(pumping station roof)

Breccia(side and front walls)

- Laboratory tests:(rock material)

.Uniaxial compression Compressive

strength

Deformabilitymodulus

Poissons ratio

.Unit weight

.Porosity

- Field tests:(rock mass)

.Boreholes (76mm) Lugeon tests Dilatometer tests

.Test pits (penstockalignment)


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CONSTRUCTION METHODCONSTRUCTION METHODCONSTRUCTION METHODCONSTRUCTION METHOD

AND PRIMARY SUPPORT SYSTEMAND PRIMARY SUPPORT SYSTEMAND PRIMARY SUPPORT SYSTEMAND PRIMARY SUPPORT SYSTEM

CONSTRUCTION METHODCONSTRUCTION METHODCONSTRUCTION METHODCONSTRUCTION METHOD

AND PRIMARY SUPPORT SYSTEMAND PRIMARY SUPPORT SYSTEMAND PRIMARY SUPPORT SYSTEMAND PRIMARY SUPPORT SYSTEM


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First forepole umbrella:

Schedule 73mm (12 m)Hill consolidation:shotcrete (10 cm), steel-wire mesh and soil nails


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Hill consolidation and executionof the first forepole umbrella

Jan.05

Feb.05


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Mar.05


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First forepole

umbrella

Pilot tunnelandPrimarysupportexecution

-Roofs primary support:

.Forepole umbrellas(3x12 m) - SCH 73 mm

.Steel ribs HEB200 // 1 m

.Shotcrete reinforcedwith steel fibers (20 cm)

.Steel wire-meshreinforcement (AQ50).


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Apr.05

Mar.05

Pilot tunnel


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Execution of cavernsroof:right side

Execution ofcaverns roof:

left side

Elephant feet(1stlevel)







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Apr.05

May05

Execution of caverns roof(right and left sides)


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Execution of caverns roof:conclusion

Elephant feet(2ndlevel)






Rockbolts(at thebase of the steel ribs)


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Apr.05

May05

Conclusion of cavernsroof execution


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-Wallss primary support:

.Rockbolts: SuperSwellex(6 m) Mesh 1,5 m x 2 m

.Self-drilling anchors (9 m)MAI R38 Mesh 1,5 m x 2 m


Downwards execution ofcaverns walls


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Jun.05


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NUMERICAL MODELLING USING THENUMERICAL MODELLING USING THENUMERICAL MODELLING USING THENUMERICAL MODELLING USING THE

FINITE ELEMENT METHODFINITE ELEMENT METHODFINITE ELEMENT METHODFINITE ELEMENT METHOD

NUMERICAL MODELLING USING THENUMERICAL MODELLING USING THENUMERICAL MODELLING USING THENUMERICAL MODELLING USING THE

FINITE ELEMENT METHODFINITE ELEMENT METHODFINITE ELEMENT METHODFINITE ELEMENT METHOD


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Alluvia:

.E = 1,0 GPa; = 0,38

.= 21 kN/m3

.c = 60 kPa; = 32

Breccia:

.E = 1,5 GPa; = 0,38

. = 22 kN/m3

.c = 80 kPa; = 36


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-3D analysis (using Plaxis):

.Total of142phases

.Mesh with29.000elements

. Rock mass: Elastoplastic (Mohr-Coulomb)

. Forepoles: Linear elastic (solid elements)

. Shotcrete: Linear elastic (plate elements)

. Rockbolts: Linear elastic (geogrid elements)


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Principal stresses Plastic points Vertical displacements


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INSTRUMENTATIONINSTRUMENTATIONINSTRUMENTATIONINSTRUMENTATION

AND OBSERVATIONAND OBSERVATIONAND OBSERVATIONAND OBSERVATION

INSTRUMENTATIONINSTRUMENTATIONINSTRUMENTATIONINSTRUMENTATION

AND OBSERVATIONAND OBSERVATIONAND OBSERVATIONAND OBSERVATION


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-Instrumentation in 6 cross sections;

-For the 2 main cross sections (P2 e P4):.2 inclinometers (average depth of 50 m);.6 vertical extensometers (in 3 holes);.12 horizontal extensometers (in 4 holes).

-For all cross sections:

.5 survey targets on the ground surface;

.Convergence meters (7 reading points in the

roof and 2 points at the sidewalls).

-On the pumping stations front wall:

.5 survey targets placed on the wall (5 levels,

in about 2/3 of the pumping stations height).

-In the hydroelectric plant:

.1 portable seismograph.


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B

6.00

9.00

12.00

1.80

2.002.00

7.80

0.50

0.50

0.50

0.50

0.50

CFI

H

D

E

A

GJ

KLM

NOP

P.V. - E0P.V. - E1P.V. - E2

I1

2.00

5.00

9.75

Galeriapiloto

Alargamento

s

Destroadir.

Destroaesq

.

Rebaixo1

Rebaixo2

Rebaixo3

Rebaixo4

Rebaixo5

Rebaixo6

-10,0

-9,0

-8,0

-7,0

-6,0

-5,0

-4,0

-3,0

-2,0

-1,0

0,0

1,0

Desloc

.verticais-PontoC(mm)

Galeriapiloto

Alargamentos

Destroadir.

Destroaesq.

Rebaixo1

Rebaixo2

Rebaixo3

Rebaixo4

Rebaixo5

Rebaixo6

-10,0

-9,0

-8,0

-7,0

-6,0

-5,0

-4,0

-3,0

-2,0

-1,0

0,0

1,0

Desloc.verticais-PontoB(mm)

VERTICAL EXTENSOMETERS

AT THE ROOFS AXIS

Plaxis 3D

Plaxis 2D

Alert

criteria

Observation(cross section P2)

Observation(cross section P4)

Pumping

stations axis


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REINFORCED CONCRETE LININGREINFORCED CONCRETE LININGREINFORCED CONCRETE LININGREINFORCED CONCRETE LINING

AND INTERNAL STRUCTURESAND INTERNAL STRUCTURESAND INTERNAL STRUCTURESAND INTERNAL STRUCTURES

REINFORCED CONCRETE LININGREINFORCED CONCRETE LININGREINFORCED CONCRETE LININGREINFORCED CONCRETE LINING

AND INTERNAL STRUCTURESAND INTERNAL STRUCTURESAND INTERNAL STRUCTURESAND INTERNAL STRUCTURES


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Pumps (16 m high)

Access

tunnel

Crane

Storagetunnel


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Jun.05

Jul.05

Sept.05


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Mar.06Sept.05


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Mar.06


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CONCLUDING REMARKSCONCLUDING REMARKSCONCLUDING REMARKSCONCLUDING REMARKSCONCLUDING REMARKSCONCLUDING REMARKSCONCLUDING REMARKSCONCLUDING REMARKS


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- The geological / geotechnical characterization included 20 dilatometer tests, very im-portant to determine the geological formations deformability characteristics it wasessential to obtain reliable parameters to the models used in the caverns design;

- The existence of a thick consolidated alluvia deposit around the pumping stationsroof, in all its length, had great importance in the construction methods and to theprimary supports that were considered;

- Important dimensions of the cavern height of 26,5 m and width of 12,5 m;

- The cavern is located at the hills toe justification to a 3D analysis, using the finiteelement method; 2D analysis were also carried out, as well as parametric analysis;

- The existing penstock was always functioning (water supply to Funchal) it had tobe protected to support the temporary rockfill and to allow vehicle passage;

- The instrumentation was defined in order to follow permanently the displacements

evolution, with the results being daily analysed the design predictions revealed agood adjustment to the observed displacements;

- Demanding design and construction schedules and deadlines.

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