NATM Applications in Singapore Ground · PDF fileGEOCONSULT NATM Applications in Singapore...

GEOCONSULT

NATM Applications in Singapore

Ground Conditions

Dr. Oskar SIGLDr. Oskar SIGL

Geoconsult Asia Singapore

1NATM Workshop 2010

TUCSS Course Singapore; 09 June 2010

Mined TunnelsMined TunnelsSHAFT-BSHAFT-BESCAPE SHAFTESCAPE SHAFT

LINKWAYLINKWAY

CIRCLE LINE (OUTER)CIRCLE LINE (OUTER)

SHAFT-ASHAFT-A

DOWNTOWN LINE (OUTER)

CIRCLE LINE (INNER)

DOWNTOWN LINE (OUTER)

CIRCLE LINE (INNER)

DOWNTOWN LINE (INNER)DOWNTOWN LINE (INNER)

2NATM Workshop 2010

Design Issues

» Understand sequence of works and

Design Issues

» Understand sequence of works and stage the excavation & support application

» At all times maintain stability of the excavation face

» Design should extend into the gconstruction phase

3NATM Workshop 2010

Excavation CycleExcavation Cycle

4NATM Workshop 2010

Cyclic Activities in TunnellingCyclic Activities in Tunnelling

» Activities (excavation, loading, mucking, support i ll i ) f d i i h ifiinstallation) are performed in sequence with specific equipment

» Typical work cycles correspond to defined excavation steps and support systems

» Collapses happen during temporary stages

Drilling

Loading and Blasting

Ventilation

Scaling

Mucking

5NATM Workshop 2010

Support Installation

Typical SequencingTypical Sequencing

6NATM Workshop 2010

Sequencing – C705 DTSS Advance TunnelSequencing – C705 DTSS Advance Tunnel

Top HeadingTop Heading

Bench

InvertInvertBack Fill

• Staged Excavation• Lattice girder, full round

7NATM Workshop 2010

• Shotcrete & wire mesh

Detailing – C705 DTSS Advance Tunnel

Top Heading

Detailing – C705 DTSS Advance Tunnel

p g

Bench

Invert B h8NATM Workshop 2010

Invert Bench

Sequencing - CCL1 C825 Overrun TunnelsSequencing DTSS/T03 TBM Launching chamberSequencing - CCL1 C825 Overrun TunnelsSequencing – DTSS/T03 TBM Launching chamber

Top Heading

Bench

Invert

9NATM Workshop 2010

Sequencing – DTL1 C905Sequencing – DTL1 C905

10NATM Workshop 2010

SequencingSequencing


Excavation Sequencing within the FaceExcavation Sequencing within the Face

FACESUPPORTING

BODYBODY

» Increase immediate Support by reduction of excavation area


Excavation Sequencing within the FaceExcavation Sequencing within the Face


Excavation Sequencing – C704 CP3Excavation Sequencing C704 CP3


Special Equipment – Tunnel ExcavatorSpecial Equipment – Tunnel Excavator


Special Equipment – Tunnel ExcavatorSpecial Equipment – Tunnel Excavator


Face Stability - ForepolingFace Stability - Forepoling

Shape of excavationwithout forepolingwithout forepoling


ForepolingForepoling

» Advance support ahead of excavation face

» Provides support for the free span = unsupported excavation surface = indirect face support

» Needs support element on its own (soil Needs support element on its own (soil and lattice girder)

» Effective only for initial support» Effective only for initial support

» Normally no permanent function at all





Shape of excavationwithout forepolingwithout forepoling

Shape of excavationShape of excavationwith forepoling


ForepolingForepoling

» Forepoling needs support element on its own (otherwise cantilever action)

» One end in soil (adequate rebar length)

» Other end rests on lattice girder (connect rebar to girder)(connect rebar to girder)

» Adequate spacing is an important » Adequate spacing is an important parameter


Face Stability – DTL 1 C905Face Stability – DTL 1 C905

Advance support ahead of excavation faceProvide support for exposed round


Provide support for exposed roundNeeds support (soil and lattice girder)



23

ForepolingForepolingHand drill (auger) with air leg – CCL C825


DTL 1 C905DTL 1 C905Stacked CCL Tunnels= LOWER by NATMy= Upper by TBM

Stacked DTL Tunnelsbelow CCL C&C

Launch Shaft A

Launch Shaft BStacked DTLLaunching chambersLaunching chambers

C&

CC

CL1


25

DTL 1 C905 – Underpassing CCL C&CDTL 1 C905 – Underpassing CCL C&C

RL 103.00

1. D-wall InstallationReclamation-----------------------

RL 80 50 m

2. Excavation and Ring Beam (Concrete)

3. Roof Slab Construction

S C

Kallang Formation

RL 80.50

RL 70.77

46.2

5m 4. Intermediate Slab Construction

5. Base Slab Construction

---------------------------Old Alluvium

TL 56.75

RL 61.257. DTL Outer Tunnel Construction

8 Backfill and Reinstate8. Backfill and Reinstate


26

DTL 1 C905DTL 1 C905Stacked CCL Tunnels= LOWER by NATM= Upper by TBM= Upper by TBM

Launch Shaft A

C&

CC

CL1


27

DTL 1 C905 – NATM with ground treatment

GROUND

DTL 1 C905 – NATM with ground treatment

Promenade StationRL 103.00

LAUNCH SHAFT A

GROUND TREATMENT BY JET GROUTING

RL. 73.34

LOWER CCLNATM TUNNEL

UPPER CCLTBM TUNNEL


28



Pipe Roof – Heavy ForepoliongPipe Roof – Heavy Forepoliong

» Support free span (unsupported length) at the faceat the face

Pi f l d h i th» Pipe roofs are longer and heavier than forepoling and of larger size

» Typically applied in difficult ground and/or for tunnelling with low overburden


Pipe RoofPipe Roof


Pipe Roof – NEL C704 TBM LaunchingPipe Roof – NEL C704 TBM Launching


Pipe Roof – CCL 3 C852 Advance TunnelPipe Roof – CCL 3 C852 Advance Tunnel


Pipe Roof – CCL 4 C855Pipe Roof – CCL 4 C855

Equipment

Drilling Jumbo


Face Support – Face BoltingFace Support – Face Bolting

» addresses sliding and spalling» cut back after each advance» continuous thread


Sequencing with Face BoltingSequencing with Face Bolting


Construction Concepts – Pilot TunnelConstruction Concepts Pilot Tunnel

Orchard Road – C825 Overrun Tunnels


Geotechnical Longitudinal SectionGeotechnical Longitudinal SectionPedestr. Underpass

Potential Faults


Orchard Road – C825 Overrun TunnelsOrchard Road – C825 Overrun Tunnels

Pilot Tunnel Concepts

Istana

Pilot Tunnel Concepts

SB CL

NB CL


Construction Concepts – Pilot TunnelConstruction Concepts Pilot Tunnel#1 Individual Pilot Tunnel

Pilot tunnel required by PS


Construction Concepts – Pilot TunnelConstruction Concepts Pilot Tunnel#2 Pilot Heading


Pilot Heading

Max forces

Pilot Heading


Horizontal Core Drilling ResultsHorizontal Core Drilling Results


Pilot Tunnel – CCL C825Pilot Tunnel – CCL C825Individual Pilot Tunnel


Pilot Tunnel – CCL C825Pilot Tunnel – CCL C825

B ki f Pil t T l d i T h di E ti


Breaking of Pilot Tunnel during Topheading Excavation

Pilot Tunnel – CCL C825Pilot Tunnel – CCL C825

Pilot Tunnel

Pil H di


Pilot Heading

Enlargement to Final Size & ShapeEnlargement to Final Size & Shape


Ventilation Cross TunnelVentilation Cross Tunnel


Ventilation Cross TunnelVentilation Cross Tunnel


Special Application – DTSS Shaft ESpecial Application – DTSS, Shaft E

» 5 Tunnels intersecting the Shaft structure» 5 Tunnels intersecting the Shaft structureDe-aeration Chamber& Back shunt T04

T06

T03


T03

Special Application – DTSS Shaft ESpecial Application – DTSS, Shaft E

» 5 Tunnels intersecting the Shaft structurestructure

Th t l i t f th» The tunnel openings remove most of the Shaft lining

» How to arrive at a reasonable approach for the structural design of temporary shaft lining


Design of Shaft Lining with Tunnel EyesDesign of Shaft Lining with Tunnel Eyes


Design of Shaft Lining with Tunnel EyesDesign of Shaft Lining with Tunnel Eyes


Application – DTSS Shaft EApplication – DTSS Shaft E


DTSS T06 – Shaft/Tunnel R2DTSS T06 – Shaft/Tunnel R2


DTSS T06 – Shaft/Tunnel R2DTSS T06 – Shaft/Tunnel R2

600mm GAS MAIN


DTSS T06/R2 – Influence Lines

Settlement Influence Lines above Crown 17.6.02 to 18.7.02


S-6116 S-6120 S-6122 S-6126 S-6127 S-6129 S-6133 S-6134

- 17.06.02 -

- 24.06.02 -

S-6135 S-6139

0

10

- 600 mm Gas Main -- 01.07.02 -

- 08.07.02 --20

-10

[mm

]

- 15.07.02 -

-40

-30

Settl

emen

ts [

TRENDLINE

-60

-50 17.06.02 24.06.02

01.07.02 08.07.02

15.07.02 trend

-7014.0 19.0 24.0 29.0 34.0 39.0 44.0 49.0 54.0 59.0

Chainage [m]



Settlement Influence Lines above Crown 17.6.02 to 19.8.02


S-6116 S-6120 S-6122 S-6126 S-6127 S-6129 S-6133 S-6134

- 17.06.02 -

- 24.06.02 -

S-6135 S-6139

0

10

- 600 mm Gas Main -- 01.07.02 -

- 08.07.02 --20

-10

[mm

]

- 15.07.02 -

- 22.07.02 -

- 12.08.02 -

- 19.08.02 -

-40

-30

Settl

emen

ts

- 29.07.02 - - 05.08.02 -

-60

-50 17.06.02 24.06.0201.07.02 08.07.0215.07.02 22.07.0229.07.02 05.08.0212.08.02 19.08.02

TRENDLINE

-7014.0 19.0 24.0 29.0 34.0 39.0 44.0 49.0 54.0 59.0

Chainage [m]

trendTRENDLINE


DTSS T06/R2 – Influence LinesSettlement Influence Lines above Crown 19.8.02 to 23.9.02

S 6127 S 6129 S 6133 S 6134 S 6135 S 613910


S-6127 S-6129 S-6133 S-6134 S-6135 S-6139

-10

0

- 600 mm Gas Main -

- 19.08.02 -

-20

[mm

]

TRENDLIN

- 22.07.02 -

- 05 08 02 -

- 12.08.02 -

19.08.02

- 26.08.02 -

-40

-30

Settl

emen

ts [

- 29.07.02 - - 05.08.02 -

- 02.09.02 -

- 09.09.02 -

- 23.09.02 -

-60

-50

S

17.06.02 24.06.0201.07.02 08.07.0215 07 02 22 07 02

- 16.09.02 -

-80

-70

32 0 34 0 36 0 38 0 40 0 42 0 44 0 46 0 48 0 50 0 52 0 54 0 56 0 58 0 60 0 62 0

15.07.02 22.07.0229.07.02 05.08.0212.08.02 19.08.0226.08.02 02.09.0209.09.02 16.09.0223.09.02 trend


32.0 34.0 36.0 38.0 40.0 42.0 44.0 46.0 48.0 50.0 52.0 54.0 56.0 58.0 60.0 62.0

Chainage [m]


Construction Progress


g

S-6116 S-6120 S-6122 S-6126 S-6127 S-6129 S-6133 S-6134 S-6135 S-6139

26 08 02

02.09.02

09.09.02

- 600 mm Gas Main -

12.08.02

19.08.02

26.08.02

29.07.02

05.08.02

Dat

e

Stop of excavation work to seal tunnel

15.07.02

22.07.02

01.07.02

08.07.02

10.0 15.0 20.0 25.0 30.0 35.0 40.0 45.0 50.0 55.0 60.0Chainage [m]


Side GalleriesSide Galleries





»Reduce size of excavation face

»Face stability

»Control of Settlements



»Make sequence only as complicated as necessary

»Avoid additional (structural) complicationscomplications


Side Galleries – Common “Design Trap”Side Galleries – Common Design Trap



Analyses result in largeAnalyses result in large horizontal deformation

L l li d ti fLarge localised section forces (particular issue = shear design)design)

Requirement for horizontal strutting due to the above

Serious construction issueSerious construction issue

Better structure ??



Better structure ??Better structure ??







Thank YouThank You

A d Glü k A fAnd Glück Auf


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