Operational analyses of pressure tunnel

and shaft grouting operationsby Helmut Wannenmacher, Sewerin Sabew and Andreas Heizmann

2

Operational analyses of pressure tunnel and shaft grouting operations

Objective:

an improvement of the lining quality & a defined coupling of the lining and the

rock mass

Basic Principles:

Pressurized grouting introduces a defined filling of a gap/ void and leads to a deformation of the lining and rock mass.

Defined relationship of grouting pressure / grouted volume and deformation

Structural Grouting

3

Grouting targets

Structural grouting targets: deformation rate effective grouting pressure and volume / grout take.

© Wannenmacher/ Krenn 2013

-2.5

-2.0

-1.5

-1.0

-0.5

0.0

08.0

9.20

12 0

6.00

08.0

9.20

12 0

9.00

08.0

9.20

12 1

2.00

08.0

9.20

12 1

5.00

08.0

9.20

12 1

8.00

08.0

9.20

12 2

1.00

09.0

9.20

12 0

0.00

09.0

9.20

12 0

3.00

09.0

9.20

12 0

6.00

09.0

9.20

12 0

9.00

09.0

9.20

12 1

2.00

09.0

9.20

12 1

5.00

09.0

9.20

12 1

8.00

09.0

9.20

12 2

1.00

10.0

9.20

12 0

0.00

radi

al d

efor

mat

ion

[mm

]

date /time

Mobile Deformation Monitoring

Strain Gauge

09.09.2012 20:46

-2.2

8

mm

mm

Date / Time

Ovalisation

Radial deformation

Mobile Monitoring Results due to IG

Start Value due toContact Groutingand Filling Phase

© Wannenmacher/ Krenn 2013

4

High pressure borehole grouting for passive pre-stressed pressure tunnel

100

rela

tive

frequ

ency

 [-]

liter / borehole [l/bh]

5 20 30 40 50 60 70 80 90

100

150

200

300

400

500

600

100

High pressure borehole grouting for passive pre-stressed pressure tunnel G

rout

Vol

. pe

r bay

[l]

5

High pressure borehole grouting for passive pre-stressed pressure tunnel

Volu

me

per

grou

t lin

e [li

ter]

Grout sections

40 80

120

1

2

3

8

4

5 9

6

7 10 11 12

0M

.S. 2

M.S

. 1

Observation:Large deviations in grout take of primary and secondary holesMinor grout take insufficient to wet the circumference of the interface

Borehole grouting system inadeqaute to crack the bonding of the lining/ shotcrete – rock mass interface (shear bond strength of ~ 0.5 MPa )

BH. Volume

Mean rad. deformation [mm]

40

80

120

0

- 0.4

- 0.6

- 0.2

- 1.0

- 0.8

- 0.6

- 1.5

- 2.0

Target deformation [mm]

6

High pressure sleeve hole grouting for passive pre-stressed pressure tunnels

High pressure sleeve hole grouting for passive pre-stressed pressure tunnels

7

High pressure sleeve hole grouting for passive pre-stressed pressure tunnel

Losses due to untight radial joints

Avg. deformation ≈ 0.35 mm 0.35 l/m⩠ 2

Avg. grout take≈ 4 l/m2

Min. grout take to heal imperfections ≈ 3.65 l/m2

8

High pressure sleeve hole grouting for passive pre-stressed pressure tunnels

Grouting pressure @manometer [bar]

Back calculated effective grouting pressure @interface [bar]

9

Low pressure borehole grouting for contact grouting of a shaft

Grout Take < 2l:7%

Grout Take ≥ 2 ≤ 7l: 68%

Grout Take > 7l: 25%

Borehole Volume = 2 Liter

Low pressure borehole grouting for contact grouting of a shaft

10

Low pressure borehole grouting for contact grouting of a shaft

Grouting Flow Test to simulate dense rock mass conditions (kf = 10-7 – 10-11 m/s)

11

Low pressure borehole grouting for contact grouting of a shaft

Grouting Flow Test to simulate dense rock mass conditions (kf = 10-8 – 10-11 m/s)

© Weh 2014

12

40μm= 0.04mm

Low pressure borehole grouting for contact grouting of a shaft

13

High pressure sleeve hole grouting for passive pre-stressed pressure tunnels

Borehole Grouting:Unfavourable orientation for crack initiation for borehole grouting.Local grouting point with a spotwise and local sphere of loading.

Comparision of sleeve hole to borehole grouting for structural grouting

Sleeve Hole Grouting:Favourable orientation for crack initiation for sleeve hole grouting, due to encasing in plastic wrap.Uniform grouting due to defined perforations in the tube a manchette system along the perimeter.Anti Bonding Agent are in favour.

14

The effective pressure acting within the gap of the final lining to rock mass correlates with the induced deformation.

Frictional loss is a system immanent parameter, which varies over time in relation on the filling grade.

Formulation of a grouting criteria for structural grouting

Final remarks on structural grouting

15

Cycle analyses of pressure tunnel grouting analyses

Grouting i.g. is repetitive operation consisting of manipulation & handling work, intrinsic grouting.

The grouting time is considered to certain extent for the execution of parallel works, as installation of packers, etc. …

Cycle analyses of pressure tunnel grouting analyses

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Cycle analyses of pressure tunnel grouting analyses

Übersetzen und erklären

0

200

400

600

800

0 10 20 30 40 50

Häufi

gkei

t

Dauer [min]

VerteilungUmsetzdauer [min]

VerteilungInjektionsdauer [min]

AnnahmeInjektionsdauerKalkulation [min]

AnnahmeUmsetzdauerKalkulation [min]

MW

Um

setz

en

MW

Inje

ktio

nReduktion 74.4%Reduktion 57%

Distribution Additional Works/ Handling Time [min]

Distribution Grouting Time [min]

Calculated Grouting Time [min]

Calculated Time for Additional Works [min]

Reduction 74%Red. 57%

Avg

. Gro

utin

g Ti

me

[min

]

Avg

. Tim

eH

andl

ing

[min

]

17

Thank you for audience !

Operational analyses of pressure tunnel and shaft grouting operations

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