EESC/USP

GeotecniaProjeto e

Construode Tneis

Design Methods 1

DESIGN METHODS

Empirical (Geomechanical

Classification)

Semi-Empirical

Observational

Rigorous

EESC/USP

GeotecniaProjeto e

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Design Methods 2

POINTS FOR DESIGN

Support Integrity

Internal Pressure

Ground Mass Load

Hydraulic Jacking

Face and Excavation Stability

Acceptable Settlements

EESC/USP

GeotecniaProjeto e

ConstruoDe Tneis

Design Methods 3

Support Design

Physical integrity

Functionality

Cost (> 30%)

Durability

Speed of water

Cavitation

EESC/USP

GeotecniaProjeto e

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Design Methods 4

Schwartz & Einstein (1980)

Semi-empirical method

1 - T, M from mass-support interaction

(2D Solution)

2 - ld correction due to support delay Ld

3 - ly correction due to ground mass yielding

EESC/USP

GeotecniaProjeto e

ConstruoDe Tneis

Design Methods 5

2*2*0 cos2112

111

2

1akak

pR

T

2cos2112

1 *22ak

pR

M

2cos16511

2

1

1

*2

*0

akak

pR

uE

p

kp

EESC/USP

GeotecniaProjeto e

ConstruoDe Tneis

Design Methods 6

1

1****

***

0FCFC

FCa

65612

16*

**

2

F

Fa

2

2*

1

1

ss

s

AE

ERC

2

23*

1

1

ss

s

IE

ERF

EESC/USP

GeotecniaProjeto e

ConstruoDe Tneis

Design Methods 7

EESC/USP

GeotecniaProjeto e

ConstruoDe Tneis

Design Methods 8

Ground Properties Support Properties Case

Radius R E Eg g h

C* F*

1 10 ft. 15000 psi 0.30 1.94 x 106 pol 0.30 6.0 in. 0.134 484.0

2A 10 5000 0.40 1.94 x 106 0.30 6.0 0.0528 191.0

2B 10 5000 0.30 1.94 x 106 0.30 6.0 0.0447 161.0

3 10 1.5 x 105

0.15 3.0 x 106

0.15 6.0 1.0 4800

4 10 1.5 x 106 0.15 3.0 x 10

6 0.15 6.0 10.0 48000

EESC/USP

GeotecniaProjeto e

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Design Methods 9

EESC/USP

GeotecniaProjeto e

ConstruoDe Tneis

Design Methods 10

R

L

T

T d

RSS

FEd 57,098,0l

EESC/USP

GeotecniaProjeto e

ConstruoDe Tneis

Design Methods 11

f

fd

u

uu 0l

E

RPu If

1

R

Ldd 57,098,0l

R

L

E

RPu dI 57,002,0

10

ss

ss

AE

PRu

22 1 us

EESC/USP

GeotecniaProjeto e

ConstruoDe Tneis

Design Methods 12

Clculo de ly

'

**

s

s

dy

P

P

T

T

ll

EESC/USP

GeotecniaProjeto e

ConstruoDe Tneis

Design Methods 13

R

b

N

NP

Eu

uI2

1

1

'

'1

1

1

1

1

1

2

N

u

uI

NP

NP

NRb

sin

sinN

1

1

sin

cu

1

cos2

21'

EE

1'

(no volume change)

EESC/USP

GeotecniaProjeto e

ConstruoDe Tneis

Design Methods 14

suporte

TT

TT

TT

P

P

yd

s

sy

54,0

33,1.41,0

33,1'

*

*

*

*

ll

l

EESC/USP

GeotecniaProjeto e

ConstruoDe Tneis

Design Methods 15

Fictitious Pressure MethodPanet (1976)

pr =

p0

pr = a.p0 pr = zero

Initial stress acting on

excavation perimeter

Fictitious pressure on

excavation perimeter

Support installation

and elimination of

fictitious pressure

EESC/USP

GeotecniaProjeto e

ConstruoDe Tneis

Design Methods 16

Load Reduction MethodPttler (1990)

p0 Cf = (1-a).p0

Final excavation and

support

Initial stress Support installation,

fictitious load, no initial

stresses

EESC/USP

GeotecniaProjeto e

ConstruoDe Tneis

Design Methods 17

Core Stiffness Reduction MethodSwoboda (1978)

En = Em En =

b.Em

En = zero

Ec reduction

Ec E of excavation zone (core)

Em E of ground mass

EESC/USP

GeotecniaProjeto e

ConstruoDe Tneis

Design Methods 18

Axissymmetric Element

EESC/USP

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Design Methods 19

Axissymmetric Element

EESC/USP

GeotecniaProjeto e

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Mtodos de Projeto 20

3-D Analysis at excavation face

EESC/USP

GeotecniaProjeto e

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Mtodos de Projeto 21

SCHWARTZ & EINSTEIN (1980) support delay Ld

0.0

0.2

0.4

0.6

0.8

1.0

0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4

Ld/R

ld=

(Tn

um

ri

co

)/(T

an

alti

co)

982.0571.0

R

Lddl

Ld=0.75m Ld=2.25mLd=3.25m

EESC/USP

GeotecniaProjeto e

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Mtodos de Projeto 22

Luf = 2.5m

Lance de escavao

Ld = 3.0m

R = 3m

Eixo do tnel

Ls = 1.0m

1 CASO

Lui = 1.5m

Ld = 3.0m

Lui = 0.75m

Luf = 2.25mLs = 1.5m

R = 3m

2 CASO Eixo do tnel

Lance de escavao

Ld = 3.0m

Lui = 0

Luf = 2.0mLs = 2.0m

R = 3m

3 CASO Eixo do tnel

Lance de escavao

PROBLEM WITH SCHWARTZ & EINSTEIN (1980)

EESC/USP

GeotecniaProjeto e

ConstruoDe Tneis

Mtodos de Projeto 23

Ld/R = 1.0

0.0

0.2

0.4

0.6

0.8

1.0

0 1 2 3 4

Z/R

T* Lui/R=0.50

Lui/R=0.25

Lui/R=0.00

~100%

PROBLRM WITH SCHWARTZ & EINSTEIN (1980)

EESC/USP

GeotecniaProjeto e

ConstruoDe Tneis

Mtodos de Projeto 24

Influence of shotcrete age on tunnel support

(Gomes, 1999)

Ld

Lui

LufLs = Le

R

Eixo do tnel

Lance de escavao

Segmento de concreto projetado curado (t > 28dias)

Segmento de concreto projetado novo (t = 1 / Velocidade)

Segmento de concreto projetado fresco (t = 0)

sL

sL

sL

sL

tN

tN

tN

tN

E

ZE

.9.0100

.3

.2.125

.25)1(

5.22

1)(

28

aa

Vt s

1

s

ui

LL

LZN

sL tNt .

EESC/USP

GeotecniaProjeto e

ConstruoDe Tneis

25

Displacement x Advance Rate

-1.1

-0.9

-0.7

-0.5

-0.3

-0.1

-10 -8 -6 -4 -2 0 2 4 6 8 10

Z/R

U*

1 m/dia2 m/dia3 m/dia4 m/dia5 m/dia6 m/dia7 m/dia8 m/dias/ sup. - FLACs/ sup. - PANETEc=const.

EESC/USP

GeotecniaProjeto e

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26

Normal Force x Advance Rate

0.0

0.2

0.4

0.6

0.8

1.0

0 2 4 6 8 10

Z/R

T* 1 m/dia

2 m/dia

3 m/dia

4 m/dia

5 m/dia

6 m/dia

7 m/dia

8 m/dia

Ec=const.