Aspects of pressure tunnel lining with special focus on pre-stressed pressure tunnels

HYDRO 2013 – Tunnels and Underground Works

«Aspects of pressure tunnel lining with special focus on pre-stressed pressure tunnels»

byHelmut Wannenmacher,

Michael Bauert and Andreas Heizmann

HYDRO 2013 – Tunnels and Underground Works

2

Background

Rock Hydraulical Conditions

Geological Conditions

EconomicalAspects

HYDRO 2013 – Tunnels and Underground Works

3

Semi-empirical Design Criteria Flow Chart

HYDRO 2013 – Tunnels and Underground Works

4

Design Criteria A:Stability of excavation during operation

• Stability of jointed rock

• Avoidance of degradation of rock mass in contact with water

Design Criteria B:Minimum Principle Stress Criteria• Internal pressure exceeds

rock mass coverage

© Weh

𝑑𝑚 . 𝑟𝑒𝑞 (𝑧 )h𝑚ax

HYDRO 2013 – Tunnels and Underground Works

5

Design Criteria C:Limiting water losses and reach of the seepage flow

• Economic losses in terms of energy caused by water losses

• Dilution of the hydrological regime

• Slope instability on the valley flanks owing to uplift conditions

Design Criteria D:Rock mass permeability / conductivity• Minimize water movements in the

vicinity of the tunnel

© Bauert

HYDRO 2013 – Tunnels and Underground Works

6

Design Criteria E:Deformation characteristics of rock mass

+ε

-p

+p

stress – strain relationship lining

stre

ss –

stra

in

rela

tions

hip

rock

mas

s

(con

solid

ated

)

stress – strain

relationship rock mass

pF(ra)pF(ra)

Increase of stiff

ness

due to consolid

ation gro

uting

strain-ε

stre

ss

strain

compression tension

HYDRO 2013 – Tunnels and Underground Works

7

Decision matrix for lining systems

HYDRO 2013 – Tunnels and Underground Works

8

Historical development of passive pre-stressed concrete linings

KW

En

zin

ge

rbo

de

n 1

96

7

KW

Ka

un

ert

al

19

63

KW

Fra

gn

an

t 19

68P

SW

Dra

ken

sbe

rg 1

98

1

PS

W K

üh

tai 1

97

9

NT

FP

20

13

Lin

tha

l 20

15

UW

ST

B 2

01

4

Lin

tha

l 20

15

OW

DS

T 2

01

3

Bä

ren

we

rk 2

01

4

0

2

4

6

8

10

12

14

16

18

20

0,0 2,0 4,0 6,0 8,0 10,0 12,0 14,0

TE

NS

ILE

RIN

G F

OR

CE

"Z

" [M

N/m

]

SLENDERNESS RATIO "SR" [m/m]

HYDRO 2013 – Tunnels and Underground Works

9

NTFP: Project Information

© Weinhard © Wannenmacher

HYDRO 2013 – Tunnels and Underground Works

10

NTFP: Design Criteria Assessment

Design Criteria NTFP

A : Long Term Stability B : Minimum Principle Stress C : Acceptable Water Losses D : Rock Mass Permeability E : Deformation Characteristics

© Wannenmacher © Perras

HYDRO 2013 – Tunnels and Underground Works

NTFP: Lining and Pre-stressing Concept

HYDRO 2013 – Tunnels and Underground Works

12

Bärenwerk Pressure Tunnel

Salzburg AG. Salzburg AG.

HYDRO 2013 – Tunnels and Underground Works

Design Criteria Bärenwerk

A : Long Term Stability B : Minimum Principle Stress C : Acceptable Water Losses D : Rock Mass Permeability E : Deformation Characteristics

Bärenwerk Pressure Tunnel

© Weh © Weh

HYDRO 2013 – Tunnels and Underground Works

14

Bärenwerk Pressure Tunnel

Shotcrete

Grout Line

Waterproofing

Final Lining

Detail 1

Detail : Excavation

Grout line

Invert segment

Mortar bed

Waterproofing membraneglued on invert segment

Shotcrete

Detail : Pre- Stressing

Grout line

Invert segment

Mortar bed

Waterproofing membraneglued on invert segment

Waterproofing membrane vault

Final lining

Intersectionwaterproofing membraneand grout line

Shotcrete

Waterproofing membranewith overlapR = 1.39m

R=1.80m

Shotcrete

Grout Line

Waterproofing

Final Lining

Detail 1

Detail : Excavation

Grout line

Invert segment

Mortar bed

Waterproofing membraneglued on invert segment

Shotcrete

Detail : Pre- Stressing

Grout line

Invert segment

Mortar bed

Waterproofing membraneglued on invert segment

Waterproofing membrane vault

Final lining

Intersectionwaterproofing membraneand grout line

Shotcrete

Waterproofing membranewith overlapR = 1.39m

R=1.80m

Shotcrete

Grout Line

Waterproofing

Final Lining

Detail 1

Detail : Excavation

Grout line

Invert segment

Mortar bed

Waterproofing membraneglued on invert segment

Shotcrete

Detail : Pre- Stressing

Grout line

Invert segment

Mortar bed

Waterproofing membraneglued on invert segment

Waterproofing membrane vault

Final lining

Intersectionwaterproofing membraneand grout line

Shotcrete

Waterproofing membranewith overlapR = 1.39m

R=1.80m

HYDRO 2013 – Tunnels and Underground Works

15

ContraContraProPro

Intense work preparation Qualified and

Experienced Grouting Operation

Monitoring and Engineeering on site required

Intense work preparation Qualified and

Experienced Grouting Operation

Monitoring and Engineeering on site required

Prooven long-term stability of pre-stressed pressure tunnels

Cost –effective method

Prooven long-term stability of pre-stressed pressure tunnels

Cost –effective method

Summary