TBM Operation for Tunneling Work (Final).pdf

METHOD STATEMENT

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TBM OPERATION FOR TUNNELING WORK

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CONSTRUCTION OF STAMFORD DIVERSION CANAL CONTRACT 2 – GRANGE ROAD TO RIVER VALLEY ROAD METHOD STATEMENT

TBM OPERATION FOR TUNNELING WORK Revision Status Rev. No.

Date

DESIGNATION

TUNNEL/ PROJECT ENGINEER

Description

DEPUTY TUNNEL MANAGER/ CONSTRUCTION MANAGER

TUNNEL MANAGER

Remarks

PROJECT MANAGER

NAME SIGNATURE DATE

SDC-C2 CONSTRUCTION OF STAMFORD DIVERSION CANAL CONTRACT 2 – GRANGE ROAD TO RIVER VALLEY ROAD

METHOD STATEMENT

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Method of Work 1. 2. 3. 4. 5. 6. 7. 8. 9. 10.

Manpower 1. Organizational/Hierarchy charge.

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Pages:

√ √ √ √ √ √ √

Hazard analysis. Preventive measures. Safe Work Procedures. Permit-to-work system. List of Personal Protective Equipment. Material Safety Data Sheet. First aid/Firefighting equipment. Tool Box Meetings. Reference to CONSTRUCTION REGULATION 10. Public Safety

Remarks

√

Remarks

√

Chart/Person-in

Health and Safety

2 of 117

√ √

Yes N.A.

√ √ √

2. List of manpower. 3. Evidence of Site Safety Induction Training. 4. Evidence of Competency Training (E.g. Trade Cert., Crane Operator’s License etc.).

1. 2. 3. 4. 5. 6. 7. 8. 9.

Rev. No. :

Yes N.A.

Date, time and duration of works. Site Plants/Schematic Diagrams. Preparatory works. Mode of transportation. Actual work/installation/delivery. Use of special equipment/machine. Hoisting operations (including hoisting Inspection/Supervision. Temporary Traffic Diversion/Control. Liaising/Interfacing with other

DOC/SDC/MS/019

Yes N.A. √ √ √ √ √

Remarks

√ √ √ √

√ SDC-C2

CONSTRUCTION OF STAMFORD DIVERSION CANAL CONTRACT 2 – GRANGE ROAD TO RIVER VALLEY ROAD

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Tools and Equipment 1. List of approved tools/equipment. 2. 110 volts for hand-held tools. 3. Relevant statutory certifications (E.g. LM Cert., LG Cert., PE Cert. etc.).

Yes N.A. √ √ √

Remarks

Materials 1. List of approved materials. 2. Schematic diagrams. 3. Data sheet.

Yes N.A. √ √ √

Remarks

Emergency Plan Yes N.A. 1. Emergency evacuation plan. √ 2. Emergency reporting procedures. √ 3. List of essential personnel with contact √ 4. Contingency Plan √

Remarks

refer to Risk Assessment


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Contents 1. Overview 2. Responsibilities 3. Equipments 4. TBM Operation A.

Reference i.

MS Entrance Portal & Ring, 1st Reaction Frame, Backing Concrete

ii.

MS TBM Cradle

iii.

MS Gantry Crane Installation

iv.

Material Submission – TBM Oil and Grease

v.

Material Submission – Foam Agent

B.

Temporary Work i.

Cradle

ii.

Entrance

iii.

Reaction Frame

iv.

Temporary Segment Support

v.

Muck Pit and Tipping Frame

vi.

2nd Reaction Frame

vii.

Single Rail and Double Rail(Y-Switch) for TBM Operation

C.

Ancillary facilities and Equipment i.

Backfill Plant

ii.

Gantry Crane

iii.

Substation

iv.

Cooling Water Tower and Water Silo

v.

Rolling Stock

vi.

1.

Locomotive

2.

Muck Skip

3.

Segment Car

Tunnel Utilities 1.

Rail Sleeper SDC-C2


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Service Pipes and Cable Hanger

3.

Backup Gantry Rail Support and Tunnel Walkway

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Operation i.

Sequence of TBM Operation 1.

2.

Initial Driving A.

Launching the TBM

B.

Umbilical Cable and Hose

C.

Erection of Temporary Segment

D.

Rolling Stock Operation Plan

Main Driving A.

Backup Gantry Setting Plan

B.

Rolling Stock Operation Plan

ii.

Soil Conditioning

iii.

Backfill Grouting

iv.

Segment Ring Building

v.

Cutter Head Intervention

vi.

1.

CHI on Planned Location

2.

Cutter Head Entry

3.

Scope of Work A.

Replacement of Cutting Tools

B.

Inspection of Geological Condition

C.

Re-Launching of TBM after Cutterhead Intervention

TBM Operation for Control the Face Pressure 1.

Face Pressure Information

2.

The Measure of Shallow Overburden

3.

A.

Sink Hole

B.

Blow Out

C.

Heaving

Operation Method A.

Settlement Monitoring

B.

TBM Parameter SDC-C2


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C. E.

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Emergency Response

Maintenance of TBM i.

Joint Plan of High Voltage Cable

ii.

Extension Plan of Ventilation Duct for Tunnel

iii.

Service Pipes

5. Appendices

Appendix A

CNR Lanzou Locomotive Co. Ltd. Company Profile and

Supply

Track Record

Appendix B

Face Pressure North and South alignment

Appendix C

Cutterhead Intervention Location along the tunnels

Appendix D

Geological profile along the tunnels based on GIBR

Appendix E

Summary of key pressure for South and North alignment

Appendix F

Settlement based on the Surfer analysis

Appendix G

Risk Assessment

Appendix H

Safe Work Procedures

Appendix I

Sample of TBM Operation Form TBM Operation Instruction Sheet Cutterhead Entry Backfill Grouting Backfill Grout Testing Record Inspection of Segment Ring Ring Building Protocol Ring Inspection Sheet Muck skip volume record


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1. Overview This method statement (MS) has been prepared to provide the methodology for TBM operation for tunneling work along Grange Road, as part of contract 2 of Stamford Diversion Canal (SDC). The tunnels are to be driven approximately 1,000 meter long using Earth Pressure Balance (EPB) shield with external diameter and internal diameters of 5.3m and 4.5m. The TBM will be launched at launching shaft located Southwest at junction Paterson Hill/Grange Road/Hoot Kiam Road/Irwell Bank Road. The TBM will be received in docking box culvert at Grange Road between Orchard Blvd. and Cuscaden Road.

2. Responsibilities 2.1 Tunnel Manager - Review of Method Statement and all the necessary permits and documents related to construct the tunnel - Coordination with the Project Manager and Construction Managers for all the relevant technical details and specifications. - Consult with SDC C2 RE’s for any discrepancies of the plan and specification, as well as alteration of the planned sequence of work.

2.2 Deputy Tunnel Manager - Ensure that the details on the plan and method statement are properly executed - Liaising with the Tunnel Manager and shift engineers for the work progress and the activities to be carried out. - Ensure that proper personnel are executing the job. SDC-C2 CONSTRUCTION OF STAMFORD DIVERSION CANAL CONTRACT 2 – GRANGE ROAD TO RIVER VALLEY ROAD

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2.3 Project Manager - Liaise with the Tunnel Manager and the Deputy Tunnel Manager regarding actual work progress and the upcoming activities - Determine the potential causes of delays and hindrances - Establish the working schedule of the tunnelling work to be constructed with respect to the baseline schedule of the total project. - Ensure that the Work Permit System is strictly followed. 2.4 Construction Manager - Manage equipment, material, manpower relevant to the job scope - Performs inspection for the facilities needed to execute the work - Assess the current working situation and determine the possible obstruction and the potential factor to cause any delays. 2.5 Shift Engineer - Assist the Tunnel Manager and the Deputy Tunnel Manager for preparation of Working Schedule. - Coordinates with the in charge person for all the necessary paperwork needed to execute the job. - Check the working situation in accordance with method statement specially the elevations and chainages are followed. 2.6 Junior Engineer - Assist the Shift engineer on monitoring of current work activities and the activities to be done. - Preparation of shop drawings and other associated documents. 2.7 Tunnel Foreman - Assist the Engineers for the supervision of the work to be executed - Co-ordinate between the Shift Engineers for tunneling work. - Supervise the Workers in performing their designated tasks 2.8 Safety Coordinator or Safety Supervisor SDC-C2 CONSTRUCTION OF STAMFORD DIVERSION CANAL CONTRACT 2 – GRANGE ROAD TO RIVER VALLEY ROAD

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- Assess all the equipments and items to be used for all the authorities rules and regulation regarding the work scope. - Check the PPEs of all the manpower executing the job and make sure that all the people involved are properly oriented of the nature and the hazards of the upcoming task. 2.9 Riggerman / Signalman / Lifting Supervisor - Ensure that all the proper coordination with their co-workers regarding the lifting works for proper execution. - All three of them should be present in any lifting work. 2.10 Scaffolding Supervisor - Supervision of their respective areas of specialization 2.11 General Workers - Facilitate welding and general works on the instruction of Supervisors, Engineers, and Managers. 2.12 Resident Surveyors/Engineers - Responsible for surveying the elevations and chainages before and after the Tunneling work. 3. Equipments Typical equipments that will required on executing the required jobs are as follows: •

35 ton Gantry Crane, Various capacity of mobile crane

•

Boom lift and lifting gear.

•

Chain Block (if necessary)

•

Air Compressor, Air auger drilling tool, rock drilling tool, Air hose

•

Localized lights

•

Various Cutting Tools(include hand breaker)

•

Ventilation fan, Grout pump, mixer, Water tank, Generator set and packer

•

Disposal Bin for scrap & hardcore


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4. TBM Operation A. i.

MS Entrance Portal & Ring, 1st Reaction Frame, Backing Concrete -

ii.

Reference

DOC/SDC/MS/015

MS TBM Cradle DOC/SDC/MS/017

iii.

MS Gantry Crane Installation DOC/SDC/MS/014

iv.

Material Submission – TBM Oil and Grease DOC/SDC/MAT/004

v.

Material Submission – Foam Agent DOC/SDC/MAT/009 B. Temporary Work i.

Cradle Assembly of the Tunnel Boring Machines (TBMs) is generally done on the TBM cradles located

on the launch shaft before the start of the excavation work. These cradles are usually the platforms that permit the site assembly of the TBMs where the machine will be at the start position. The cradle for this project consists of H beams, stiffener plates, connected by bolts and fillet welds. These steel structures are designed to withstand the heavy loads of the TBM parts during and after assembly, this will be installed on top of the concrete base slab. Please refer to MS DOC/SDC/MS/017 for details.


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Figure 1: The Cradle


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Figure 2: Cradle Elevation View

Figure 3: Cradle Plan View


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Figure 4: Cradle Front View and Details

ii.

Entrance The Tunnel Entrance is designed to support the Tunnel face from possible water seepage and

collapse. The Entrance will serve as the seal of Entrance Portal to prevent ground water flow through the gap between the shaft wall and TBM skin during the break-in on the sheet pile wall line. This will also aid to stabilizing the proper alignment of Tunnel Boring Machine for entering the Tunnel drive. For launch of the Grange Road to Orchard Boulevard junction, the tunnel entrance is located adjacent to the strengthening wall and sheet pile at C2 launching shaft. Chainage for the North tunnel SDC-C2 CONSTRUCTION OF STAMFORD DIVERSION CANAL CONTRACT 2 – GRANGE ROAD TO RIVER VALLEY ROAD

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entrance is from CH-N-1016.62 to CH-N-1013.646 (2.97m width). The South tunnel entrance is from CH-S-1028.2 to CH-S-1025.23 (2.97m width). Please refer to MS DOC/SDC/MS/015 for details.

Figure 5: The Completed Tunnel Entrance

iii.

Reaction Frame The 1st Reaction Frame is designed to resist 16,000 kN of thrust force from Tunnel Boring

Machine during launching and initial driving stage. Reaction frame is considered as essential part of the launch as this will aid to serve as the TBM during first stages of its advance. The calculations for the item are provided by the Design Consultant that is engaged on determining if the components to be used are sufficient enough to withstand the jacking force on the thrust load induced by the TBM. Please refer to MS DOC/SDC/MS/015 for details. SDC-C2 CONSTRUCTION OF STAMFORD DIVERSION CANAL CONTRACT 2 – GRANGE ROAD TO RIVER VALLEY ROAD

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Figure 6: The 1st Reaction Frame

iv.

Temporary Segment Support The Temporary Segment Support is designed primarily to support the TBM during the initial

stage of operation in installing segment ring. The Structure is consists of H-beams 300x300x10x15, and steel plates connected by bolts and nuts. This structure will be installed on each side of the Cradle.


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Figure 7: Temporary Segment Support Plan View


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Figure 8:


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Figure 9:

v.

Muck Pit and Tipping Frame Muck pit is designed to an area suitable for collecting excavated materials during TBM

driving. Muck was removed by means of small muck car and transported to the muck pit ground level. A muck pit of capacity 315m3 was constructed on this project beside the shaft wall at the ground of each tunnel drive. An excavator will be used to load the excavated spoil inside the muck pit onto dump truck for off-site disposal. However, Tipping Frame is a structure that will aid the muck car to dispose the excavated material to the muck pit. This structure is consisting of 450x450 H-beam which is designed to hold the muck car and rotate it for disposal. The following figures show the Plan and details of this structure and the operation procedure. SDC-C2 CONSTRUCTION OF STAMFORD DIVERSION CANAL CONTRACT 2 – GRANGE ROAD TO RIVER VALLEY ROAD

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Figure 10: Muck Pit Plan


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Figure 11: Tipping Frame with 11m3 Muck-skip

Figure 12: Plan and Details of Tipping Frame


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Figure 13: Tipping Frame Fabrication Drawing

The following figures show the procedure during operation;

Figure 14


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Figure 15

Figure 16


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Figure 17

vi.

2nd Reaction Frame The 2nd Reaction Frame is designed to resist 16,000 kN of thrust force from Tunnel Boring

Machine during launching and initial driving stage. Reaction frame is considered as essential part of the launch as this will aid to serve as the TBM during first stages of its advance. As TBM advances to the grouting area, the 2nd Reaction frame will be installed at the rear part of TBM. This is to support the rear assembly of TBM in installing the segment ring. 2nd Reaction Frame will be installed in the following sequence of procedures:


METHOD STATEMENT


Figure 18

Figure 19

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1. Installation of T1 to T7 half Segment

2. Installation of T8 to T9 Temporary Segment TBM advances as approaching the Grouting area


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Figure 20

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3. Installation of 2nd Reaction Frame between T1 to T7 Before advancing to the Grouting area

Figure 21

4. From T10 Initial Driving to the Grouting area Will commenced.


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Figure 22

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5. after the installation of P4 Segment Backfill Grouting on Grout area

Figure 23

6. The temporary Belt conveyor for initial driving Will be installed after the installation of P7 segment


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Figure 24

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nd Reaction Frame will then

7. The Rear part of 2

Removed from T1 to T7 and will be installed in Front

Figure 25

8. T8 to T13 Temporary Segment will then remove.


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Figure 26

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nd Reaction Frame will then installed between T1 and

T6

Figure 27

10. 2nd Reaction Frame will then installed between T7 to T13


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Figure 28

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11. Installation of Locomotive

Figure 29: The 2nd Reaction Frame


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Figure 30

vii.

Single Rail and Double Rail ( Y-Switch ) for TBM Operation Single Rail and double rail with Y-switch are to be used during TBM main driving. Single Rail

will be installed after setting the back-up Gantry. Length of Y-switch should be determined first as conformed to its design. However, the double rail approximately 100m length from tunnel entrance up to the end of back-up Gantry. Construction of these Single and double rail will reduce the cycle for TBM operation in SDC-C2 CONSTRUCTION OF STAMFORD DIVERSION CANAL CONTRACT 2 – GRANGE ROAD TO RIVER VALLEY ROAD

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transporting excavated muck.

Figure 31

Figure 32


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Figure 33

Figure 34: Y-Switch Rail Plan


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Figure 35: Elevation view of Y-Switch Rail

C.

Ancillary Facilities and Equipment

i.

Backfill Plant Backfill Plant is an ancillary facility for injection tail void grouting during TBM driving.

This consists of cement silo, bentonite tank, sodium silicate tank, mixer and etc. for feeding mixed grout to Tunnel Boring Machine. There will be electrical control panel for setting the figure of mix design. Mix design of tail void grouting to be discussed and proposed on next section of this MS for SDC C2 project. Figure 36 is shown the drawing of backfill plant which is to be used at SDC C2 project. SDC-C2 CONSTRUCTION OF STAMFORD DIVERSION CANAL CONTRACT 2 – GRANGE ROAD TO RIVER VALLEY ROAD

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Figure 36: Backfill Plant

ii.

Gantry Crane Gantry Crane is main lifting equipment for TBM tunneling work. The crane is used for

disposal of excavated material, lowering the precast segment to Launching shaft, setting the TBM backup trailers, general lifting work and etc. There will be a lot of activities. The gantry crane for SDC C2 project is manufactured by BD Crane Tech Pte. Ltd., one of the crane manufacturers in Singapore. The capacity is 35 ton of safe load and 60m runway on site. For reference, design drawing is attached as figure 37 and MS Gantry Crane Installation.


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Figure 37: Gantry Crane Design

iii.

Substation Generally, Tunnel Boring Machine needs electric power supply for operation. 11kV high voltage will be connected between Transformer on TBM and Substation. Also substation will be provided low voltage as well for all electrical work on site. The detail will be provided. Please refer to the figure 38 which is the flow chart of electric power on SDC C2 project.


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Figure 38: The flow chart of electric power on SDC C2 for Tunneling work. iv.

Cooling Water Tower and Water Silo Tunnel Boring Machine is required cooling water for cooling down the temperature of hydraulic parts and soil conditioning, grouting work. Water consumption volume (ton) will be about 9,000ton/month. Cooling water will be provided 25℃ ~ 29℃ temperature of water for tunneling work.

v.

Rolling Stock The Rolling Stock is transportation for Tunneling work. This consists of Locomotive, Muck skip, Segment car. The operation method on TBM initial driving or main driving will be discussed on next section of this MS.


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Locomotive For SDC C2 project, the locomotive is manufactured as diesel operation. The dimension is

6,800mm (L) x 1,200mm (W) x 1,850mm (H) with 750mm of rail gauge according to Tunnel dimension and TBM backup trailers dimension. Manufacturer is SCHOMA LOKOMOTIVEN which is one of locomotive manufacturer in Germany. The figure 39 is shown the drawing of locomotive for SDC C2 project.

Figure 39


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Muck Skip The purpose of Muck skip is disposal and transport excavated materials from tunnel to

surface. There are 6 nos. of muck skip which are 1 nos. of 13.5m3 muck skip for TBM initial driving and 5 nos. of 11m3 muck skip for TBM main driving. All muck skip will be equipped spring loaded brake system at each wheels (Called air brake system). The manufacturer is CNR Lanzhou Locomotive Co., Ltd in China. Please refer to the company profile and supply track record as Appendix A. The table. 1 is shown the dimension and specification of muck skip and figure 40, 41 is shown the drawing of muck skip which is to be used for SDC C2 project.

Table. 1 : The specification of Muck skips

Type

3

11m

3

13.5m

Part

Description

Dimension

7,000mm(L) x 1,230mm(W) x 2,100mm(H)

Rail gauge

750mm

Wheel base

3,500mm

Wheel diameter

400mm

Designed speed

25km/h

Braking force

6kN per each wheel

Dimension

7,000mm(L) x 1,600mm(W) x 1,970mm(H)

Rail gauge

750mm

Wheel base

3,500mm

Wheel diameter

400mm

Designed speed

25km/h

Braking force

6kN per each wheel


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Figure 40: 11m3 muck skip


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Figure 41: 13.5m

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3 muck skip

Segment Car

The main purpose of segment car is for transportation of the segment into Tunnel. Also it will be used for transportation of materials, tunnel service pipes and TBM dismantling work. Two (2) segment cars will be used for SDC C2 project. One of segment car is 15ton loading capacity and the other is 30ton loading capacity as considered heavy load such as TBM dismantling in the future. According to PUB (LTA) M&W specification, the segment car is equipped spring loaded brake system at each wheel (Called air brake system). The manufacturer is CNR Lanzhou Locomotive Co., Ltd in China as same with muck skip manufacturer. Please refer to


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Table 2 for further specification. The figure 42 and 43 is shown the drawing of segment car which is to be used for SDC C2 project.

Table. 2 : The specification of Segment car

Type

15 ton

3o ton

Part

Description

Dimension

3,756mm(L) x 1,230mm(W) x 530mm(H)

Rail gauge

750mm

Wheel base

2,000mm

Wheel diameter

400mm

Designed speed

25km/h

Braking force

6kN per each wheel

Dimension

5,756mm(L) x 1,230mm(W) x 530mm(H)

Rail gauge

750mm

Wheel base

2,200mm

Wheel diameter

400mm

Designed speed

25km/h

Braking force

6kN per each wheel


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Figure 42: 15ton Segment Car


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Figure 43: 30ton Segment Car

vi.

Tunnel Utilities Tunnel Utilities consists of rail sleeper, hanger for various cables and pipes, tunnel walkway and TBM backup trailer rail support. Those are supported for tunnel operation. The details are as below. 1. Rail Sleeper The purpose of rail sleeper is to support for Rolling stock operation which is related with tunneling work. Rail sleeper is designed according to rail gauge distance of rolling stock, 38kg/m rail dimension which is standard size in Singapore for SDC C2 project. Furthermore, it is all in one type with TBM backup gantry rail support (Can be used as Tunnel walkway as well.) and hanger SDC-C2


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support of various cables and pipes. The figure 44 ~ 48 are shown the design drawings. This will be fabricated on workshop and to be installed as 1.2m distance on invert of every segment ring. 38kg/m rail specification is attached for reference as figure 49 and 50. PE endorsement drawing for Rail Sleeper will be submitted separately.

Figure 44: Rail Sleeper with Backup Gantry Rail Support in Tunnel.


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Figure 45: Rail Sleeper with Backup Gantry Rail Support Detail


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Figure 46: A part of Rail Sleeper with Backup Gantry Rail Support.

Figure 47: B part of Rail Sleeper with Backup Gantry Rail Support.


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Figure 48: Walkway and Hanger for Cables, Pipes in Tunnel.


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Figure 49: Dimension of 38kg/m Rail


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Figure 50: 38kg/m rail Standard Specification in Singapore.

2. Service Pipes and Cable Hanger For Tunnel Boring Machine (TBM) operation, there are power cable, communication cable and pipe lines. The purpose of hanger in tunnel is support for connection cables and pipes between ancillary facilities and TBM. The List of Service pipes and cables are mentioned below Table 3. Figure 51 is shown the design of hanger for SDC C2.


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Table. 3: List of Service pipes and cables in Tunnel

Cable

Communication Cable (Internet, Survey,

Pipe

1” size for Sodium Silicate (Backfill Grouting)

etc)

Low Voltage Cable

2” size for Grouting (Backfill Grouting)

11kV High Voltage Cable

2” size for Bentonite (Face pressure) 2” size for Cleaning water 4” size for Compressed Air (2 Lines) 4” Cooling Water (2 Lines)(TBM operation) 4” Dewater (TBM operation)


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Figure 51: Hanger for cables and pipes 3.

Backup Gantry Rail Support and Tunnel Walkway

TBM Backup gantries are equipped 4 set of double wheel. It is required to install the rail support for advance with TBM. Also there is required safe walkway for workers, engineers, others in Tunnel. This support is designed for 2 purposes. One is support for Backup gantry rail, other is walkway for tunnel worker after Backup gantry pass from this support. Please refer to the figure 52 which is proposed design for SDC C2 project. PE endorsement drawing will be submitted separately. SDC-C2 CONSTRUCTION OF STAMFORD DIVERSION CANAL CONTRACT 2 – GRANGE ROAD TO RIVER VALLEY ROAD

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Figure 52: Tunnel Walkway


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D. Operation i.

Sequence of TBM Operation

1. Initial Driving This method statement for S-975 HTM EPBM’s for Stamford Diversion Canal Contract 2 covers the safety and efficient operations and procedures that are related to the initial drive for the two bored tunnels (North and South Bounds). Initial Drive is following completion of which will be TBM and back-up rearrangement work. The method statement will also cover the preparation work for Initial Drive, TBM and backup trailer setting, installation of temporary ring, TBM brake out procedure, and EPB TBM initial drive excavation procedure, it has been written in this MS to describe the safe working procedures as well. A. Launching the TBM Preparation work prior for Initial Driving The following items/activities should be ready before launching the S-975 HTM EPBM’s for Stamford Diversion Canal Contract 2 Launching Shaft: Setting up of TBM cradle and TBM Reaction Frame Back-up Trailer installation on shaft Grouting Plant installation 35 Ton Gantry Crane installation, including testing and commission Tunnel Survey system and TBM Guidance System Temporary Ventilation fan installation Installation of services (piping) to TBM Entrance Ring and packing / flapper installed SDC-C2 CONSTRUCTION OF STAMFORD DIVERSION CANAL CONTRACT 2 – GRANGE ROAD TO RIVER VALLEY ROAD

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All relevant documentation and test certificates will have been established All Lifting gear available and certified All crew are well trained for their tasks

TBM Break out Prior to TBM break out, the following items must be prepared; Temporary and permanent rings, including all segment accessories. Grouting plant fully operational with stock of cement, bentonite, sodium silicate, stabilizer etc, with piping connected to the TBM. Compressed air procedures had been finalized and understood by the tunnel team. All necessary training for operator had been done and the operators well trained for their task, the operators including; o

TBM operator

o

Grouting Plant operator

o

Segment erector operator

o

Locomotive operator

TBM parameter for the first 100m TBM excavation procedure including all documentation, quality control, test certificate, etc. All crew had been inducted for tunneling operation. All lifting lugs of TBM had been removed. Welding stopper at TBM body to prevent TBM rolling or toppling during initial breakout. SDC-C2 CONSTRUCTION OF STAMFORD DIVERSION CANAL CONTRACT 2 – GRANGE ROAD TO RIVER VALLEY ROAD

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Emergency procedures and contingency plan in place and understood by all personnel. Emergency equipment materials in place, such as sand nag, wood, steel beam, and water pump, etc. Other necessary preparations for break out.

EPB TBM initial Drive Excavation Procedure EPB TBM initial drive excavation procedure will follow the TBM parameter for the first 100m from Grange road (nearby T218) to River Valley Road (nearby T220). However, the TBM parameters may change depending on the actual ground condition. Other parameters such as jack speed, thrust force, cutter toque, jack selection etc will be instructed by the Tunnel Engineer or Tunnel Manager.

Face pressure and excavated soil volume will be controlled and monitored to prevent over excavation that may result in ground movement or settlement. Face pressure and excavated soil volume will be controlled by the TBM operator and monitored by the Tunnel Engineer. The TBM operator will be following the instruction sheet prepared by the Tunnel Manager. Initially and until it is practicable to set up the conveyor belt system, excavated soil will be removed from the cutter chamber thru the screw conveyor and discharged into a muck skip. The size of the muck skip will be decreased such that at first a full skip can be pushed to the shaft bottom only by the workers. The full muck skip will be transported to the shaft bottom, hoisted up using the 35-ton SDC-C2 CONSTRUCTION OF STAMFORD DIVERSION CANAL CONTRACT 2 – GRANGE ROAD TO RIVER VALLEY ROAD

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Gantry crane or mobile crane and emptied using the tipping frame inside the mucking pit. Backfill grout to fill the annulus between TBM over cutting and segment extrados is batched on the surface and pumped a storage tank at the back up trailer. From the storage tank the backfill grout material (liquid A and B) is pumped to the grout port. Procedure for Backfill grouting will be submitted under MS for Backfill Grouting. TBM guidance system will be using IRIS and checked by Tunnel Surveyor and Tunnel Engineer. TBM alignment will be controlled by the TBM operator. Segment selection (type and key position) will be done by the Tunnel Engineer who will ensure that the segment selected follows the design tunnel alignment and has enough clearance between segment extrados and TBM tail skin. Procedure for segment ring building show under item (iv.) Segment Ring Building of TBM Operation. Tail Seal Grease. When the tail seals have passed over temporary ring No.13, they will be automatically packed with grease by the “on-board” grease pumps. The volume of tail seal grease injected will be limited to a value as required. Initial Grouting sequence. Once grease has been injected and the entrance packing had been adjusted to the extrados of the segmental lining, the TBM will be advancing for the last section of permanent ring No.1. Grout will be injected through the tail skin. During grouting, the grout should also come out via bleed ports also installed in the entrance concrete. The grouting process will continue until grout is flowing out from the pipe located at the crown of the entrance concrete pacing. The volume of the grout used per ring will be recorded and kept in the Backfill Grout Record Sheet. Where flow is SDC-C2 CONSTRUCTION OF STAMFORD DIVERSION CANAL CONTRACT 2 – GRANGE ROAD TO RIVER VALLEY ROAD

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restricted or there is undue pressure build up, the grout injection point will be changed accordingly until all voids are full. Great care will be taken to ensure that the annulus has been completely filled. If any leaks are discovered on striking the entrance packing. It may be deemed necessary to drill and instigate secondary grouting. Ground Conditioning. Initially, we will only be injecting water/foam through the ground conditioning ports. The rate will be adjusted to maintain optimum TBM operation. Once the machine has passed through the sheet pile area, ground conditioning will be injected to suit conditions. Foam may be used to reduce the stickiness. In any case, as the initial drive progresses and ground conditioning agents are in use with regularity, polymer injection will be controlled and monitored. It is actually very difficult to predict ground conditioning parameter in advance of the tunneling work. The dosages and types of materials will be adjusted until they give the soil conditions that are best suited. After completion of the Initial drives and after track and TBM rearrangement works, it will now be possible to bring in a full train compliment of segment trolleys, Locomotive, 11m3 Muck skips. The ventilation ducting and other back-up utilities not previously connected will already be connected to the TBM gantries.


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SUMMARY SEQUENCE OF INITIAL DRIVE;

Figure 53

Sequence 1 » Once the umbilical connected into back-up car and TBM Assembly completed, the Reaction Frame will be installed, T1 to T7 install only half segment.


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Figure 54:

Figure 55:


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Sequence 2,3 » TBM Pushing stop before touched Grouting area (Install T8 & T9), Install 2nd Reaction Frame between T1 to T7. Sequence 4 » From T10 Start Initial Driving into Grout Area. Prior TBM shoving the 2nd Reaction Frame should be endorsed by PE for loading capacity.

From T10

Figure 56:

Sequence 4 » From T10 Start Initial Driving tinto Grout Area. Prior TBM shoving the 2nd Reaction Frame should be endorsed by PE for loading capacity.


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Figure 57:

Sequence 5 » From P4 segment after start Backfill Grouting into Grout area.


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Figure 58:

Sequence 5.1 » After Erection P7 segment Install Temporary Belt Conveyor for Initial Driving.

Figure 59:


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Sequence 6.1 » Removal 2nd Reaction Frame between T1 to T7

Figure 60

Sequence 6.2 » Removal top position segments of the ring 6 nos. of temporary rings will be removed. Access is mainly necessary to lower down and lift up the muckskips, segments and materials.


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Figure 61

Sequence 6.3 » 2nd Reaction Frame Re-Install between T1 to T6

Figure 62


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Sequence 6.4 » 2nd Reaction Frame Install between T7 to T13

Figure 63

Sequence 6.5 » Lower down Locomotive, When 2nd Reaction Frame will be installed. Prior TBM shoving the 2nd Reaction Frame should be endorsed by PE for loading capacity.

B.

•

Umbilical Cable and Hose

Electric Cables A 200 m. long 11 kV trailing cable will be stored on a cable reel on the rear of the TBM back-up

gantry. As the tunneling progress the cable is fed out and hold to the right hand side wall of the tunnel SDC-C2 CONSTRUCTION OF STAMFORD DIVERSION CANAL CONTRACT 2 – GRANGE ROAD TO RIVER VALLEY ROAD

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at knee position with brackets. When the TBM has progressed approximately 200 m; tunneling stops and the trailing cable is disconnected from the cables along the tunnel isolation for high voltage switching. A new cable is run from the previous cable to the rear of the back-up gantry. The trailing cable is recovered, and rolled back onto the cable reel using the air motor, and the ends of the cables are joined using couplers ready for tunneling to recommence.

The Umbilical Line Plan

Figure 64


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Umbilical line has to be connected by prior start TBM excavation; Six (6) no’s. Cutter motor cable should be connected each cutter motor. Umbilical cable and hose are will be disconnect & moving position when dismantle of Temporary Segment and Install 2nd Reaction Frame. Lower down Locomotive and when 2nd Reaction Frame install after Umbilical line should be Reconnection inside permanent ring.

SERVICES LAYOUT •

Intercom line

:

•

Ventilation pipe

:

For ventilation.

•

High voltage line

:

Electricity supply for TBM operations.

•

Low voltage line

:

For lighting inside tunnel.

•

Spare pipe

:

Spare for the case Block.

•

Backfill pipe A

:

Solution A for Backfilling (refer backfill Grouting)

•

Backfill pipe B

:

Solution B for Backfilling (refer backfill grouting

Communication lines.

grouting) •

Cooling Water line

:

TBM cooling system.

•

Air supply line

:

Carry out the air for compressed air

•

Drain water pipe

:

Removal of drain water

•

Rail Sleeper

:

Support Rail for Locomotive or Rolling stocks

•

Backup Gantry Support

•

Pipe Rack

:

Hanging the Pipes

•

Walkway Support

:

Put the walkway plate on it

•

Cable Rack

:

All kinds Cable Hanging

:

Support Rail for moving Backup Trailers


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C. Erection of Temporary Segment

Temporary Ring Installation (Ring No.1)

Figure 65:

1. As pre decided that first key on the top (i.e. Key position K, right lead 40 look up or overhang) place the segment on the feeder with the help of 35T Gantry crane. 2. Preparatory arrangement before ring build, weld 2 or more as per site requirement Nos. 65x65mm square bar in TBM tail shield square bar use to give the clearance from tail skin. 3. Mark the centre of TBM by survey team on the tail skin with respect to the thrust frame to prevent the excessive roll of the ring. 4. Start to place the segment with help of erector correct positioning of the first plate A2, with respect to survey centre line marked on the tail skin. It would be braced on the tail skin with the help of four number stiffener plates 200×340x 20 and dowel bar (2 back of the segment +2 front of the segment), stiffener numbers may be change as per the site requirements. SDC-C2 CONSTRUCTION OF STAMFORD DIVERSION CANAL CONTRACT 2 – GRANGE ROAD TO RIVER VALLEY ROAD

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5. Install segment A3 adjacent to A1 with dowel bar circumferentially. For making clearance between the segment and the tail skin would use wooden wedge. 6. In similar manner install A1 adjacent to A2. 7. Install segment C it with adjacent segment A1, support it with erector till L- bar (200x340x 20) weld to the skin at the overhang edge. 8. In similar fashion as erected the segment A2, erect segment C it with adjacent segment B, support it with erector till L-bar weld to the skin at the edge. 9. Check the gap between segment A2 and segment C, and then insert the key segment. 10. After completion of the ring check the bolts tightness and then cut off the stiffeners. 11. Fill the tail seal grease with manual/mechanical mechanical to the three rows of wire brush. 12. Weld some stopper to the TBM outer shield with the cradle. 13. Before pushing of the complete ring no1 to thrust frame see all around the ring there should not be any obstruction, then apply one jacks per segment at least (at the most jacks) .which would just touch the front edge of the ring . Cut the stiffeners one by one. Then apply the trust (hydraulic pressure adjustment to the lower side of pressure would be done in consultation with HK team) slowly and uniformly to ring against to the thrust frame. Continue with the next ring building.

D. Rolling Stock Operation Plan Rolling Stock is the general term covering all non powered rails mounted equipment use in the tunnel, including muck cars, man rider, segment transport cars, material transport flatcars, etc.


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The scope of this method Statement is to describe the methodology operation of the locomotive train and Rolling stock within the tunnel and shaft. These rolling stock / locomotive are equipment for use as transportation for all tunnel related materials aligns the bored tunnel. The Procedures are outline to ensure the loco operations within the bored tunnel and shaft bottom are well carried out in a safe way manner.

Figure 66


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2. Man Driving

Establishment of Construction Plan Sub Station

Design, Fabrication and Delivery of Shield Machine

Construction of Launching Shaft

Preparation of Initial Drive

Erection of Back up Facilities above ground Setting up Platform & Back Truss for Thrust Force Erection of Shield Machine, Site Testing & Commisioning

Ground Improvement Initial Drive

Erection of Temporary Segments

Preparation of Main Drive

Dismentle Temporary Segments and Back truss

Relaunch all Rolling Stocks, ventillation…. etc into the Tunnels Main Drive Reinstall Raised Platform, Rails

Break Through (Docking)

Dismantle Shield Machine & Backup system

Cross Passage

In-situ Lining (SCL)

Casting of 1st Stage Concrete

Dismantle rails…etc & cleaning


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Excavation (TBM Advance) The cutter head rotation speed and direction is set by the TBM Operator considering the following: • The TBM Operator selects the rotation of the cutter head as either clockwise or counter clockwise as required for the actual roll status of the machine; • The cutter head speed is increased from zero using the control knob and is adjusted if required, dependant on ground conditions and cutter head torque. Generally speed between 1.0 and 2.5 revolutions per minute (rpm) will be used in soft ground and maximum speed (4.3 rpm) will be used in rock conditions and slow speed in mix face; • To change the head direction once started, the cutter head will first be stopped. • The thrust rams are powered in four groups and in order to activate the thrust rams: Each group can be driven at different pressures to facilitate steering without overloading the segmental lining; • Steering can be achieved by applying greater pressure on particular group of thrust rams; and • Each full stroke is nominally 1200 mm. however the rams will be extended in the range 600 - 1800 mm. to allow the key to be installed for the 1200 mm. • Face pressure and excavated soil volume will be controlled and monitored by Tunnel Engineer. TBM Operator will follow the “TBM Operation Instruction Sheet given by Tunnel Engineer; • The calculation of “Face Pressure” will submit separately. However, face pressure applied may differ depend on the actual ground condition, which is decided by Tunnel Manager; and • Excavated soil volume will be controlled and compared to the theoretical soil volume and statistical mean of excavated soil volume. • The TBM Operator will advance the TBM within the guidelines of the “TBM Operation Instruction Sheet for maximum advance rate, thrust, and contact force and machine torque. It is important for settlement control that the TBM advance rate does not exceed the backfill grouting rate. • As the stroke proceeds the TBM Operator will monitor the discharged estimated excavation volume SDC-C2 CONSTRUCTION OF STAMFORD DIVERSION CANAL CONTRACT 2 – GRANGE ROAD TO RIVER VALLEY ROAD

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from bulk scanner or muck skip counting, face pressure, the grout intake, grout pressure and the actual and predicted positions are calculated using the IRIS and details provided on the monitor in the Operator‘s cabin. • Once the TBM has completed the advance and with the thrust cylinder pumps still running, the advance and cutter head rotation is stopped and control passed over to the Erector Operator. • The displaceable main drive allows accurate loading on the cutter head and face to be determined (contact force). If the cutter head strikes an obstruction, the main bearing is protected by hydraulic interlocks. A face inspection would be carried out in the event of an obstruction being encountered. A. Backup Gantry Setting Plan Backup Gantry Setting plan is the safety and efficient operations and procedures that are related to the Main drive for the two bored tunnels (North and South Bounds). Initial Drive is following setting Backup Gantry near the cut & cover tunnel and surface of available area. When S-975 HTM EPBM’s TBM machine reaches approximately 96m which will be TBM and back-up need to rearrangement work from entrance to Cutter Head. Approximately 96m all of Backup Gantry (6 no’s) can set tunnel inside. The method statement will also cover the preparation work for Main Drive Backup trailer setting. The main worksite and staging area for the tunneling back-up facilities on the ground will be located near the cut and cover tunnel, utilizing the area to set-up equipment/machineries, plants, and staging areas for the tunneling works as here under described as follows;

Figure 67


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Figure 68

Figure 69


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Figure 70

B. Rolling Stock Operation Plan Rolling Stock is the general term covering all non powered rails mounted equipment use in the tunnel, including muck cars, man rider, segment transport cars, material transport flatcars, etc. The scope of this method Statement is to describe the methodology operation of the locomotive train and Rolling stock within the tunnel and shaft. These rolling stock / locomotive are equipment for use as transportation for all tunnel related materials aligns the bored tunnel. The Procedures are outline to ensure the loco operations within the bored tunnel and shaft bottom are well carried out in a safe way manner.


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Figure 71

ii.

Soil Conditioning The soil conditioning agent will be injected to cutter face, excavation chamber and screw

conveyor as well. The injection rate will be controlled subject to ground condition in order to stabilize the face pressure and to improve the fluidity and water tightness. In order to maintain a stable chamber pressure, excavated material should be a homogenous mix of coarse and fine particles, improving overall plasticity of the material. Required physical properties of an excavated material are achieved through conditioning it with foam, polymer, bentonite or simply water, creating a paste like consistency. Proportions of foam constituents are selected depending on actual type and gradation of excavated material as well as expected ground pressure. Additional benefits of ground conditioning include reduced water permeability of conditioned ground as well as reduced stickiness and clogging of the materials, facilitating efficient mining. Appendix B shows the Face pressure for North and South alignment.

During mining the following should be monitored and adjustments made as required. •

TBM parameters; i.e. Face pressure, thrust speed, cutter torque and thrust force

•

TBM position

•

Excavated material flow and condition

•

Volume of excavated materials

•

Grout pressure and volume SDC-C2


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Overall TBM Behaviour

Soil condition Foam agent (MAK Foam) : Please refer the Material Submission ~ DOC/SDC/MAT/009

iii.

Backfill Grouting Generally, Backfill Grouting is main activity for TBM tunneling work. Basic principle of TBM tunneling work is shown the drawing as figure ( 72 ).

Figure 72

As shown figure 72 , Backfill grout will be injected through grouting injection port in TBM tail skin. The purpose of backfill grouting is filling the gap between TBM O.D (ø5, 290mm) and Segment O.D (ø5, 000mm). SDC-C2 CONSTRUCTION OF STAMFORD DIVERSION CANAL CONTRACT 2 – GRANGE ROAD TO RIVER VALLEY ROAD

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For getting sufficient strength of grout, high quality of grout materials are to be used for SDC C2 project and compressive strength test will be carried out on site once a day. Material submission of grout materials will be submitted after trial mix under PUB/CPG supervision. The requirement for backfill grout mix is as follows. Bleeding

<5%

Gel Time(After mixing with accelerator

4~15 sec

Before the next shove commence

>50kPa as M&W Specification 16.2.13

29 days compressive strength

>2MPa as M&W Specification 16.2.13

The proposal mix design for grout material is shown as figure Table 4. Test report will be submitted separately.

Table 4:

Mix Design for Backfill Grout.


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The minimum, maximum and Grouting pressure will be submitted on TBM instruction sheet by Tunnel Manager. iv. Segment Ring Building One complete ring consisting of six (6) number segments is transported to the TBM by the train, stacked in pairs on segment car. Hydraulic lifting arms on the segment handler will lift the segments from the segment car in pairs and position on the segment handler. The vacuum pad crane will then be used to lift the top segment in each pair and arrange them individually in the segment handling area. The segments can be selected in any order required for the ring build sequence. The segments will be delivered and stacking should be in manner as shown in Figure 73.

Figure 73

SDC-C2


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The temporary will be lowered down to the launch shaft by using 35-ton gantry crane or mobile crane and proprietary lifting device. The segment will then be transported to the segment feeder device. Refer to figure (74 and 75).

b)

The reaction frame will be marked with the correct internal and external diameter of the ring. By using wedges and jacks in addition to the roundness retainer, the correct shape and level of the rings can be ensured. Once in position, angle bar or other proprietary steel section will be welded to shove frame to keep the ring in position. Holes may be burnt in the shove frame in positions that tally with the bolt pockets of the segments. Bolts can then be used to secure the ring. This will be confirmed at site if appropriate or not.

c)

Tail seal grease will be applied manually at the TBM tail seal brush.

d)

A total 13 no’s of temporary rings will be installed for each of Bounds tunnels.

e)

For the temporary rings, segment that has minor non-conformances will be used; these segments are able to be used for TBM launching purpose – i.e. the segments are structurally sound. They may or may not be coated. Gasket or packing will not be installed for temporary rings.

f)

For the permanent rings, only accepted segments will be used complete with coating, EDPM gasket and packing; these segments prior to use should have been checked and accepted.

g)

The temporary rings will be lowered down to the shaft onto a segment car by using the 35 ton gantry crane or mobile crane and certified lifting device. The segments are unloading to the segment feeder where it available and brought into the segment erection area. The ring will be installed inside the TBM by using the TBM erector.

h)

The ring level and roll will be checked; and during erection, the segment will be secured to prevent rolling and other movement. The segment will be drilled into the joint of the 2 segment into steel plate to prevent moving when retracting the rams.

i)

Once ring erection is completed, the ring will be pushed slowly toward the reaction frame by thrust SDC-C2


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jacks. C-channels will be welded at the reaction frame as support and guide during pushing the segment to the reaction frame. j)

Once the ring is in position, wire rope with turnbuckle will be put around the segment extrados to secure its shape during TBM excavation. TBM turnbuckle will be used remove any slack in the wire rope.

k)

The process will be repeated until all temporary rings are constructed. During each shove for ring outside the ground, Tunnel Supervisor / Engineer will observe the ring condition, support, TBM position and attitude with respect to tunnel eye opening; TBM will be closely monitored especially when the tail skin passes beyond the end of cradle.

l)

Every temporary ring will be checked as to the level and chainage to ensure the correct positioning of the first permanent ring. The following figures show the sequence of Ring Building:

Initial Driving

Main Driving

Figure 74 SDC-C2 CONSTRUCTION OF STAMFORD DIVERSION CANAL CONTRACT 2 – GRANGE ROAD TO RIVER VALLEY ROAD

METHOD STATEMENT


Initial Driving

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Main Driving

Figure 75

Figure 76

1. The 1st Ring segment Installation The

segment

will

be

transported

by

segment car.


METHOD STATEMENT


2. The 1st Ring segment Installation

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Figure 77

The segment will lift using dowel pin.

st Ring segment Installation

3. The 1

Figure 78

The segment will be set to its position

4. The 1st Ring segment Installation

Figure 79

The dowel pin will be inserted to the dowel socket.


METHOD STATEMENT


5. The 2nd Ring segment Installation The

dowel

pin

will

served

as

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Figure 80

the

connection of each segment

6. The 2nd Ring segment Installation

Figure 81

The segment will be pushed by Thrust jack to connect and tightened.

7. The cycle of installation will continue by

Figure 82

inserting dowel pin into dowel socket for the next segment ring


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Figure 83

Figure 84

Figure 85: The Completed Ring Segment


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Cutter Head Intervention 1. CHI on Planned Location The Stamford Diversion Canal Contract 2 has two alignments, the North and South alignment.

The Tunnels are to be driven approximately 1,000 m long using Earth Pressure Balance (EPB) shield with external diameter and internal diameters of 5.3m and 4.5m. Cutter head interventions will be planned in advance whenever possible to ensure that the cutter head is located in stable ground conditions in order to enable the entry of personnel. Planned interventions are generally intended for inspections of the cutter head prior to tunneling beneath critical structures such as roads and buildings along the route to see the actual ground condition as well as through difficult ground conditions; planned replacement of cutting tools, or for removal of obstruction inside the cutter head chamber. The cutter head / cutting wheel are part of the TBM. Inspecting the cutter head / cutting wheel and its excavation tools is therefore necessary to prevent major damage on the cutter head / cutter wheel. Appendix C shows the Planned Cutterhead Interventions.

Table 5 : Planned Interventions for the South Alignment drive

No.

Chainage (m)

Nearest borehole

Distance from nearest building (m)

Pressure, half face (bar)

Pressure, full face (bar)

1

105.0

BH4-2d

23

0.75

1.00

2

284.5

BH4-2a

35

0.96

1.21

3

425

BH4-3g

27

0.84

1.09

4

556

NBH-12

24

0.83

1.08

5

720

BH4-3a

11

0.57

0.82

6

872

NBH-6

53

0.48

0.73

Comments Access shaft 2 Maintenance shaft Access shaft 4


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Table 6 : Planned Interventions for the North Alignment drive

No.

Chainage (m)

Nearest borehole

Distance from nearest building (m)

Pressure, half face (bar)

Pressure, full face (bar)

1

90.0

BH4-2d

15.8

0.73

0.98

2

228.5

NBH-16

12.5

1.04

1.29

3

375

BH4-2c

15

0.86

1.1

4

471

NBH-13

15.5

0.81

1.06

5

591.4

NBH-11

11

0.82

1.07

6

690.0

BH4-3a

14

0.59

0.84

7

815

NBH-7

47

0.51

0.76

Comments Access shaft 1

Maintenance shaft Access shaft 3

2. Cutter Head Entry In the event where TBM advancement is becoming unexpectedly difficult such as cutter head torque increase/decrease or thrust force increase with low advance and penetration rates, and if the wear detectors mounted on the cutter head indicate that the cutting tools are worn down, the unplanned Intervention are required. TBM may encounter obstructions such as construction waste, boulders or piles, etc. The Unplanned Intervention will be required a Cutter Head Entry permit to be accomplished by the project concerned personnel. 3. Scope of Work There are possibilities that man-made obstructions could be encountered during tunneling fill material. These obstructions may include construction waste, abandoned road pavement layer and shallow foundations. The obstruction may become trapped on the cutter head or damage to cutter head. Removing the obstructions or change the cutting tools covers the scope of work of Cutter head Intervention. SDC-C2 CONSTRUCTION OF STAMFORD DIVERSION CANAL CONTRACT 2 – GRANGE ROAD TO RIVER VALLEY ROAD

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A. Replacement of Cutting Tools During TBM operation, the cutting tools of TBM Cutter head will be monitored as to different circumstances. Replacement of cutting tools may be necessary when the wear detectors mounted on the cutter head indicates that the cutting tools need to be replaced. The TBM will be stopping on the stoppage location defined in Cutter head Intervention Plan or as the case may be to Unplanned Intervention. The ground condition will be checked by competent person before the replacement of cutting tools.

B. Inspection of Geological Condition Anticipated ground conditions for tunneling have been assessed based on the GIBR. The tunneling will be encountering the weathered granite G(VI). Mixed soil conditions, consisting of a mixed face of the G(VI) and fill layer are anticipated locally on all drives. Table 7 : General ground conditions anticipated along the route of the SDC tunnel, North Alignment, based on the GIBR.

Chainge from

Chainage to

(m)

(m)

Anticipated Ground Conditions at Tunnel Face

N-0

N-50

G(VI)<0.5D cover to Fill layer

N-50

N-160

0.5D
N-160

N-330

G(VI)>1D cover to Fill layer

N-330

N-710

0.5D
N-710

N-1018


Table 8 : General ground conditions anticipated along the route of the SDC tunnel, South Alignment, based on the GIBR.


METHOD STATEMENT


Chainge from

Chainage to

(m)

(m)

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Anticipated Ground Conditions at Tunnel Face

S-0

S-50


S-50

S-160

0.5D
S-160

S-340

G(VI)>1D cover to Fill layer

S-340

S-730

0.5D
S-730

S-1029


A variable thickness of fill soils is shown above the tunnel in the GIBR. According to the tables, the G(VI) that is just over the tunnel crown or could be present over the face locally is shown in some areas of Chainage 600, 700, and 900. Those chainages are represented by borehole BH4-3c, BH4-3d, and BH4-3e for chainage 600, 770, and 900, respectively. However, site investigation report of BH43e provides>3m cover of G(VI) over the tunnel crown that is different with what is shown on the soil profile drawings. The long section of GIBR soil profile is attached in Appendix D. C. Re – launching the TBM after cutter head intervention Once the Cutter head Intervention work has completed, TBM will be advancing slowly and fill-up soil in the chamber and the air will be discharged slowly for balancing the face pressure. vi.

TBM Operation for Control the Face Pressure Controlling the face pressures to the limits will depend on the skill of the operator and the

effectiveness with which the soil conditioning is adjusted to suit the varying conditions along the alignment. 1. Face Pressure Information The ground losses can be controlled by applying the sufficient face pressure, injection of the thick bentonite slurry using system installed on the TBM, simultaneous tail void grouting suing the system installed on the TBM. With the use of the slurry injection system and good control of tail void grouting the volume of the ground loss can be reduced significantly. The value of the volume loss also depends on the workmanship. Appendix E and Appendix F shows the summary of Face Pressure SDC-C2 CONSTRUCTION OF STAMFORD DIVERSION CANAL CONTRACT 2 – GRANGE ROAD TO RIVER VALLEY ROAD

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information. 2. The measure of Shallow Overburden The recommended face pressure for the residual soil of Bukit Timah Granite is 0.4 to 0.6 of the total overburden pressure. It could be reduce to free air when undrained shear strength is reach to 100 kPa at the depth of the 20m below ground surface. This face pressure is only for the case of the full face of the residual soil of Bukit Timah Granite. A. Sink Hole Sink Hole occurs when the excavated volume of soil is bigger than the calculated design volume. This occurs in unstable ground condition such as sand, gravel, sandy soil of low viscous force.

Figure 86


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TBM Drive

1. If excavated Muck

TBM Operator must follow TBM Operation

Maintenance Face Pressure

Instruction Sheet

•

Torque

•

R.P.M.

•

Thrust Force

•

Thrust Speed

volume is bigger inform the Engineer in charge 2. If possible Sinkhole is found: •

Inform

TBM

operator

Continue Drive

•

Inform

Tunnel

Manager Finish Drive

1. If excavated Muck volume is bigger inform the Engineer in charge

Segment

2. If possible Sinkhole is

Erection

found: •

Inform

TBM

operator Preparation TBM Drive

•

Inform

Tunnel

Manager

The Flow Chart illustrates that during Tunnel operation, the TBM operator must carefully followed the TBM instruction sheet. The parameters that should be checked are the following: 1. Torque 2. R.P.M. 3. Trust Jack Force 4. Thrust Speed 5. Face Pressure Excavated Muck volume must be monitored, in the event that the muck volume is bigger than the calculated volume the TBM operator must inform the Engineer and watchman to check the surface condition to prepare for necessary safety procedures if possible Sinkhole is found. SDC-C2 CONSTRUCTION OF STAMFORD DIVERSION CANAL CONTRACT 2 – GRANGE ROAD TO RIVER VALLEY ROAD

METHOD STATEMENT


B.

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Blow out

Blow out occurs when the pressure at the crown exceeds the total overburden pressure, the ground may rapture leading to a blow out of the compressed air. This causes a severe risk to the safety of those working in the compressed air and to the public at the surface. For this project the residual soil and fill material will be encountered with same permeability at the face and above the tunnel crown the risk of heave due to compressed air is impossible. However, the risk of the pressure blow-out for both semi and open modes are investigated. The factor of safety against blow-out was checked for the case where the excavation chamber is emptied to invert level. The factor of safety is less than 1.2 for the chainages below. Therefore full emptied of the chamber is not recommended and the cutterhead intervention should be performed in the semi-EPB mode. Table 9 : The locations where the full face intervention is not recommended

Tunnel North Bound

From N-10.0 to N-30.0; and From N-730.0 to N-990.0

South Bound

From S-10.0 to S-30.0; and From S-800.0 to S-980.0

Figure 87


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•

Torque should be maintained in any geological condition.

•

R.P.M. should be maintained for each ground condition, when approaching weak ground R.P.M. is 1-1.5.

•

Initial & Main Driving R.P.M. is 1-3.5.

•

If R.P.M. is increases or decreases, ground relaxation should increased.

•

R.P.M. must be checked for each ground condition.

•

Thrust jack force should be control to maintain Face pressure.


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Thrust force can be increased, in case of high Torque.

•

Thrust speed should be increased, when Thrust force is high.

•

Face Pressure should be inspected when decreases gradually

95 of 117

C. Heaving The pressure required to cause unacceptable ground heave is effectively the pressure required to lift the overburden block of ground. This pressure is equal to the in-situ stress at the tunnel level plus a value based on the strength of the ground loss. If the maximum face pressure is kept at or below the total vertical overburden pressure, there should be no risk of excessive heave in ground surface during construction of the tunnel. For the below locations the minimum grout pressure to ensure effective grouting was greater than the pressure required to heave the ground surface. To avoid the excessive heave, the maximum grout pressure was reduced to 85% of the total overburden plus the pressure needed to overcome the shear strength of the ground

considering a factor of safety of 1.2.

Table 10 : Chainage of shallow depth tunnels with risk of excessive heave due to high grout pressure Tunnel

Chainage

North Bound

From N-10.0 to N-160.0; and From N-340.0 to N-1008.0

South Bound

From S-10.0 to S-160.0; and From S-350.0 to S-1019.0


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Figure 88


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•

Torque should be maintained in any geological condition.

•

R.P.M. should be maintained for each ground condition. When approaching weak ground, docking R.P.M. should only at 1-1.5.

•

Initial and Main Driving R.P.M. 1-3.5.

•

Thrust force should be maintained for Face Pressure.

•

Thrust force can be increased, in case of high Torque.


METHOD STATEMENT

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•

Thrust speed can be decreased when Torque reaches high.

•

Face Pressure should be inspected when gradually increases.

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3. Operation Method The operation methods are preliminary based on existing soil investigation. The Operation method includes the following:

Part

Description

Target Face Pressure

All the time

Controlling

TBM advance rate, B/F Grouting

Monitoring (24 Hrs.)

TBM Parameter, Surface

Visual check

Muck Condition, Volume

2nd Grouting

Immediately (After pass through)

Proper usage for soil condition

Foam, Polymer, Bentonite

A. Settlement Monitoring The target volume loss figures of calculations are shown in Table below:

Tunnel

Chainage

Volume Losss

From

To

North Alignment

0+000

1+018

0.7%

South Alignment

0+000

1+029

0.7%

These target volume loss figures have been used as a basis for the rate and grouting pressure calculations. However, these calculations are for short term settlement when tunneling EPB mode only. There are number of potential causes of settlement which are not directly related to the face pressure used and which therefore cannot be directly controlled with the face pressure. These include: 1. Consolidation settlement due to dissipation of excess pore pressures generated during tunneling, leakage into the tunnel or bleeding of the tail void grout. SDC-C2 CONSTRUCTION OF STAMFORD DIVERSION CANAL CONTRACT 2 – GRANGE ROAD TO RIVER VALLEY ROAD

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2. Settlement associated with interventions. 3. Settlement due to boulders, pieces of rock or other obstructions being trapped in or rolled around the cutter head, and causing damage to the ground in and above the face of the tunnel. 4. The construction of the cross-passage, maintenance shaft, and access shaft. Settlements due to these causes are excluded from the calculated target volume loss, and will be additive to the volume loss. While these potential sources of additional settlement are not directly related to the face pressure used, in most case (excluding leakage into the tunnel and bleeding of the grout) the use of the calculated target face pressure will help to minimize the risk of and/ or magnitude of settlement due to these potential additional sources. Appendix G shows the Settlement based on Surfer analysis.

B. TBM Parameter The parameters that must be observed for TBM operation are the following: •

Torque

•

R.P.M.

•

Thrust Jack Force

•

Thrust Speed

C. Emergency Response In the event that it is necessary to contact Emergency Services to report on emergency, the person is to follow the instructions on the Emergency Reporting Instructions. These instructions are to be posted at the surface and tunnels. All accidents/incidents are to be reported to the Project Manager of TS and LTA. SDC-C2 CONSTRUCTION OF STAMFORD DIVERSION CANAL CONTRACT 2 – GRANGE ROAD TO RIVER VALLEY ROAD

METHOD STATEMENT


•

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The internal telephone network provides the primary means of communication in an emergency.

•

Telephones are maintained at the surface and tunnel underground.

•

Emergency response from underground is achieved by the provision of emergency lines direct to telephones in the main office area.

•

A person appointed as a Tunnel Safety Supervisor will be in attendance on the tunnel at all times.


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E. Maintenance of TBM i.

Joint Plan of High Voltage Cable A 200 m. long 11 kV trailing cable will be stored on a cable reel on the rear of the TBM back-up

gantry. As the tunneling progress the cable is fed out and hold to the right hand side wall of the tunnel at knee position with brackets. When the TBM has progressed approximately 200 m, tunneling stops and the trailing cable is disconnected from the cables along the tunnel, isolation for high voltage switching and a new cable is run from the previous cable to the rear of the back-up gantry. The trailing cable is recovered, and rolled back onto the cable reel using the air motor, and the ends of the cables are joined using couplers ready for tunneling to recommence.

ii.

Extension Plan of Ventilation Duct for Tunnel While excavation is stopped during the ring build cycle or even Excavation time. It is possible

to extend exchange the ventilation duct canister. All materials and equipment is stored on the TBM backup gantry, having been transported to the TBM on flat car pushed by locomotive. Typically delivered and installed during maintenance shift. For ventilation within tunnel, forced-air supply method will be used; that provides fresh air into tunnel with ventilation pump installed on the ground above the vertical pit (launch Shaft). It shall be noted that the below computations and analyses for the ventilation system shown hereunder are for sample computation for one tunnel only.


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A) Installed FAN Specification

Flux

Q = 200m3/min

Wind Pressure

p = 200mmAq

Model

: Blower Type, TFB-22M, 3550rpm, 44KW

Operation Type

: Both automatic and manual

Duct in tunnel

: 1 row of Ventilation tube (Φ1000mm)

B) Calculation of Necessary Volume of Ventilation

Necessary Volume of Ventilation per 1 worker in tunnel = 3 m3/min

Q = 15 * 3m3/min = 45 m3/min

In-addition, the usage of diesel locomotive will require an additional air circulation of another 25% of the normal ventilation requirement.

i.e; the flow rate required

= 45 x 1.25 = 56.25 m3 / min


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But the effect of diesel locomotive won’t be disturbing the workers at the TBM, as the air circulation will be as shown below and locomotive will be working at the rear part of the backup system; refer to below sketch. Since the locomotive will be located at the rear part of the backup system throughout the operation, the outward flow of air will remove the effect of smoke away from the working area at the TBM.

Figure 89

Calculation of Necessary Wind Volume of Fan

m

m

= β * (L/100)

m

: Wind Loss Ratio,

β

: Wind Loss Coefficient=0.015,

L

: Duct Length=1000m

Qf

: Necessary Wind Volume of Fan,

Q

: Necessary Volume of Ventilation =45 m3/min)

= 0.015 * (1100/100)

= 0.165


METHOD STATEMENT


Qf

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= Q/(1-m) = 45 m3/min ÷ (1-0.165) = 53.89 m3/min

Calculation of Necessary Wind Pressure of Fan

ν

: Wind Velocity in Tunnel m/sec

Q

: Necessary Volume of Ventilation =45 m3/min

r

: Duct Radius=0.5m,

h

: Loss due to Duct Pressure =mmAg

λ

: Duct Friction Coefficient=0.025,

L

: Duct Length=1100m

γ

: Air Gravity=1.2kg/m3

g

: Acceleration of Gravity=9.8m/sec²

hf

: Necessary Wind Pressure of Fan mmAg

m

: Wind Loss Ratio =0.294

ν

= Q / (15 * π * r²) = 45/ (15 * π *0.5²) = 3.82 m/sec SDC-C2


METHOD STATEMENT


h

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= (λ * L * ν² * γ) / (r * g) = (0.025 * 1100 * 3.82² * 1.2) / (0.5*9.8) = 98.28 mmAg

hf

= h/(1-m) = 98.28/(1 - 0.165) = 105.11 mmAq

∴

200mmAq > 105.11 mmAq - - - - - O.K

Ventilation System Details

However, there should be some emergency ventilation during man to access the front of the shield machine; the ventilation system used will be the same as for the temporary shaft: a)

Multi-gas detection meters will be installed at intervals.

b)

Oxygen mask & cylinder harness – will be kept in adequate numbers as stand -by for

emergency rescue. c)

Ventilator blower (compressor or motor) located topside as shown in Figure 90.

d)

Ventilating blow tubes – canvas/plastic foldable circular tubes of about 800mm diameter.

It is

connected to the ventilator blowers on ground level, and run down vertically to the shaft base. e)

The ventilation system will be in continuous operation in the launch shaft & tunnel. The installation of duct shown in Figure 90.


METHOD STATEMENT


Ventilator

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Ø800mm

Figure 90: Vent Duct placement

iii. Service Pipes While excavation is stopped during the ring build cycle. It is possible to extend service pipes, rails, electric cable and exchange the ventilation duct canister. All materials and equipment is stored on the TBM backup gantry, having been transported to the TBM on flat car pushed by locomotive. Services, other than pipes and rail, are typically delivered and installed during maintenance shift. It is intended that pipe joints will be staggered to minimize the number of service changes at a particular time. Services are extended by shutting the nearest valves either side of the pipe to be extended carefully bleeding of the air or water by slowly opening the bleed valve on the end of the back-up gantry/ hoses, then disconnecting the hose and inserting a new pipe. The rail track can be laid using the overhead crane at the front of the first back-up gantry. The rail will be installed to a standard to minimize maintenance and risk of the derailments. Rail gauge 750mm. and tolerance is -3mm. to +15 mm. SDC-C2 CONSTRUCTION OF STAMFORD DIVERSION CANAL CONTRACT 2 – GRANGE ROAD TO RIVER VALLEY ROAD

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APPENDIX A

CNR LANZHOU LOCOMOTIVE CO.LTD. COMPANY PROFILE AND SUPPLY TRACK RECORD


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APPENDIX B

FACE PRESSURE NORTH AND SOUTH ALIGNMENT


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APPENDIX C

CUTTERHEAD INTERVENTION LOCATION ALONG THE TUNNELS


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APPENDIX D

GEOLOGICAL PROFILE ALONG THE TUNNELS BASED ON GIBR


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APPENDIX E

SUMMARY OF KEY PRESSURE FOR SOUTH AND NORTH ALIGNMENT


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APPENDIX F

SETTLEMENT BASED ON THE SURFER ANALYSIS


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APPENDIX G

RISK ASSESSMENT


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APPENDIX H

SAFE WORK PROCEDURES


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APPENDIX I

SAMPLE OF TBM OPERATION FORM TBM Operation Instruction Sheet Cutterhead Entry Backfill Grouting Backfill Grout Testing Record Inspection of Segment Ring Ring Building Protocol Ring Inspection Sheet Muck Skip Volume Record


TBM Operation for Tunneling Work (Final).pdf

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