151567785 01 tunnel boring machine tbm specifications

8/20/2019 151567785 01 Tunnel Boring Machine Tbm Specifications

1/32

PART VIII - MATERIAL AND WORKMANSHIP SPECIFICATIONTUNNEL BORING MACHINE (TBM) SPECIFICATIONS

i

CONTENTSPage No

MNW/TBM/

1. INTRODUCTION..............................................................................................................................1

1.1 Definitions .................................................................................................................................1

2. GENERAL........................................................................................................................................ 2

2.1 TBM Selection Criteria..............................................................................................................2

3. CLOSED FACE MACHINES ...........................................................................................................3

3.1 General ..................................................................................................................................... 3 3.2 Cutterhead and Cutters ............................................................................................................4 3.3 Cutterhead Drive.......................................................................................................................5 3.4 Shield Body, Propulsion and Tailskin ....................................................................................... 6 3.5 Compressed Air Provision ........................................................................................................8 3.6 Probing and Ground Treatment................................................................................................9 3.7 Erector ....................................................................................................................................10

4. PARTICULAR REQUIREMENTS FOR SLURRY MACHINES .....................................................10

4.1 General ...................................................................................................................................10 4.2 Slurry Circulation ....................................................................................................................11 4.3 Slurry Treatment Plant............................................................................................................13

5. PARTICULAR REQUIREMENTS FOR EPB MACHINES ............................................................16

5.1 General ...................................................................................................................................16 5.2 Screw Conveyor .....................................................................................................................16 5.3 Soil Conditioning.....................................................................................................................17

6. BACKUP SLEDGES......................................................................................................................17

6.1 General Requirements............................................................................................................17

7. ALIGNMENT CONTROL ...............................................................................................................18

7.1 General ...................................................................................................................................18 7.2 TBM Guidance Control ...........................................................................................................18

8. ELECTRICAL SPECIFICATION....................................................................................................19

8.1 General Requirements............................................................................................................19 8.2 Controls and Instrumentation..................................................................................................20

9. SAFETY .........................................................................................................................................21

9.1 Regulations.............................................................................................................................21 9.2 Work in Compressed Air.........................................................................................................21 9.3 Fire Prevention .......................................................................................................................22 9.4 Environmental Monitoring .......................................................................................................22 9.5 General Requirements............................................................................................................23

10. MANUFACTURING & COMMISSIONING.....................................................................................23

10.1 General ...................................................................................................................................23

11. TBM OPERATION & USE .............................................................................................................24

11.1 General ...................................................................................................................................24 11.2 Assembly and Erection ...........................................................................................................24 11.3 Operation and Maintenance ...................................................................................................24 11.4 Primary Grouting.....................................................................................................................26 11.5 Secondary Grouting................................................................................................................27


2/32


ii

11.6 TBM Dismantling ....................................................................................................................27

12. DOCUMENTATION .......................................................................................................................28

12.1 At Proposal Stage...................................................................................................................28 12.2 After Award of Contract ..........................................................................................................28

12.3 Manufacturing Progress Report..............................................................................................30 12.4 After Commencement of Tunnelling .......................................................................................30


3/32


268831MC/North-South Transmission Cable Tunnel – Contract NS2 MNW/TBM /1

1. INTRODUCTION

1.1 Definitions

1.1.1 “Shield” is defined as a tunnelling machine comprising a cylinder of metal that isforced forward through the ground and which protects those working within it whoare excavating the ground at the leading edge. The tunnel lining, if made ofsegments, will be erected in the tail of the shield within the “tail skin”. The shieldwill house thrust rams at the periphery which force the shield forward by jackingfrom the last completed ring of segments. A means of excavation is mountedwithin the shield or alternatively excavation may be by hand tools.

1.1.2 “Semi mechanised tunnelling machine” means a shield equipped with excavatingmachinery (road header, boom excavator, or bucket excavator) which isindependent or semi-independent from the shield and which will allow access to

the face without entry into a separate chamber.

1.1.3 “TBM” (Tunnel Boring Machine) is a machine comprising excavating machinerywhich excavates the full tunnel profile. A TBM may be mounted within a shield –a shielded TBM, or may not have the protection of a shield (e.g. in hard rock), -an un-shielded TBM.

1.1.4 “A closed face TBM” consists of a shielded TBM where the cutterhead can rotatewithin an enclosed chamber, which can be pressurised to provide support to theground and hydrostatic pressure encountered. This is a pressurised closed facemachine. If the chamber is not pressurised but allowed to remain at atmosphericpressure it is an unpressurised closed face machine.

1.1.5 “An open face TBM” is defined as a shielded TBM where there is no pressurechamber or bulkhead and the material is loaded onto a conveyor at atmosphericpressure.

1.1.6 “Slurry TBM” is a closed face TBM used in pressurised mode where the pressuremedium is a slurry, usually bentonite, which is used to carry the excavatedmaterial from the face and is cleaned and re-circulated.

1.1.7 “EPB TBM” is a closed face TBM used in pressurised mode where the pressuremedium is made up from the ground excavated together with conditioning fluidswhich are added as the material is excavated. The conditioning fluid may befoam, polymer, bentonite or water. The pressure is maintained by releasing the

excavated material slowly through a screw conveyor at a rate consistent with theTBM advance.

1.1.8 “Commissioning” refers to the first 200 metres of tunnel construction during whichthe equipment is first tested under load and all the operating systems andinstrumentation can be tuned and set up correctly.


4/32



2. GENERAL

2.1 TBM Selection Criteria

2.1.1 The Contractor’s proposed TBMs must be able to control ground movements,including both settlement and heave, under all foreseeable circumstances withinthe geological conditions anticipated, as described in the Contract documents,including mixed face conditions, and thus negate any risk to buildings and otherstructures in the vicinity of the tunnel alignment.

2.1.2 The Contractor shall carry out the works using the same type of machinesubmitted at Tender stage and shall not be permitted to use any other type ofmachine or supplier than those proposed in his Tender, unless accepted by theEngineer.

2.1.3 The design of the TBM shall be based on inter alia, consideration of the geology

anticipated, the ground and groundwater conditions, the alignment anddimensions of the tunnel, and the stability of face and surrounding ground duringexcavation and prior to placement of the permanent support, minimising groundloss and consolidation settlement whilst maintaining programmed advance ratesthroughout the length of the drive. A detailed description of the ground conditionscan be found in the Geotechnical Interpretative Baseline Report (GIBR). TheGIBR shall be studied for full details of the anticipated geology and hydrogeologyalong the alignment.

2.1.4 The Contractor shall demonstrate that his proposed TBM and backup / supplyand spoil removal systems can achieve the advance rates required to meet theprogramme dates.

2.1.5 The TBM(s), including all components used, and all associated plant shall besupplied brand new. The Contractor shall be fully responsible for the selection,design and supply of the TBM’s and all ancillary equipment used, notwithstandingany of the requirements stated in this specification which shall be suitable for theconditions anticipated.

2.1.6 The TBM shall be manufactured in units of convenient size, suitable for erectionon site and for dismantling under the site conditions of this Contract. All of themain components and any single item weighing in excess of 10 tonnes shall havetheir weight in metric tonnes clearly marked on them prior to shipping.

2.1.7 The Contractor shall include in his TBM design submission, calculations to showthat the TBM will be able to negotiate the tight horizontal and vertical tunnelalignment with sufficient clearance between the TBM tailskin and the extrados ofthe tunnel lining rings to allow the TBM to turn through all curves on thealignment without causing damage to the tunnel lining rings.

2.1.8 The TBM shall be designed to construct a suitable precast concrete lining, whoseinternal diameter shall be 6.0 metres, 300mm thick and suitable for the geology


5/32



and depths of tunnel anticipated. The Contractor shall consider all constructiontolerances in the design.

2.1.9 Notwithstanding requirements stated elsewhere, it shall be entirely the

Contractor’s responsibility to select and procure the tunnelling equipment that issuited for the conditions and will meet schedule and performance and safetyrequirements.

2.1.10 The Contractor shall fully acquaint himself with the anticipated geologicalconditions. The proposed TBM shall be capable of overcoming all anticipatedconditions while maintaining the required advance rates and face pressures forcontrol of settlement. Considerations shall be given, but not limited to thefollowing:a) Mixed face conditions;b) Blockages;c) Abrasivity;d) Core stones; and

e) Any other conditions that may affect the programme.

3. CLOSED FACE MACHINES

3.1 General

3.1.1 The TBM’s shall be designed and manufactured in conformity with therequirements of the Standards listed in Clause 9.1.1.

3.1.2 The machine shall have the capability to handle, break up as required and

remove boulders / blocks through the spoil discharge system, whether it is acrusher and slurry discharge or a screw conveyor, or any other spoil dischargesystem without causing blockages to the system.

3.1.3 All closed face machines shall be designed to maintain pressure on theexcavated ground at all times during the process of excavation at programmedrates and during any period when changing cutters, carrying out any repairs,during probing, during segment installation and when idle for extended periods.

3.1.4 The machine shall be able to balance the total overburden pressure, includinghydrostatic pressure, and this applied face pressure shall be capable of beingvaried as the overburden pressure changes. Face pressure shall be maintained

at ±0.1 bar of the required set pressure.

3.1.5 A suitable, dewatering system shall be installed in the shield and ring build areato ensure that any seepage from the face can be controlled. This should pump toholding tanks near the rear of the backup from where it can be pumped out of thetunnel.


6/32



3.2 Cutterhead and Cutters

3.2.1 The cutterhead shall be capable of bi-directional rotation, clockwise oranticlockwise, and shall only be able to excavate the ground whilst the hydraulic

rams are being actuated. The design shall ensure that the cutterhead can beretracted back from the unexcavated ground to minimise the risk of thecutterhead jamming and to facilitate maintenance. Such rearward movementshall not require rearward movement of the tail shield.

3.2.2 The cutterhead shall incorporate a full face of 19 inch single disc cutters,arranged with a maximum spacing of 85 mm. These shall be extra heavy dutygrade (long life) cutters (utilizing cutting rings with a minimum hardness ofRockwell Rc 55) where Granite (GI – III) is encountered. They shall be backloading type capable of being changed from within the cutterhead.

At least 2 gauge roller discs cutting on the same outer most cutting path be

provided to minimise the chance of TBM getting stuck in the rock due to reducedcutting diameter. In addition a measuring device be provided on the TBM todetect the amount of overcut to minimise the risk of TBM getting stuck in rock.

3.2.3 The tip of all disc cutters, at its limiting wear criteria shall lead any soft groundtools fitted by at least 40 mm and the offset ahead of the main cutter headstructure shall be sufficient to allow the excavated material to move freely awayfrom the face without becoming trapped between the face and the surroundingcutter head structure.

3.2.4 A high degree of cutter wear is likely on the TBMs. The TBM should be designedto facilitate the swift changing of cutting tools. In his submission the Contractorshould state how he will minimise this down time and highlight any features he

will incorporate on his TBM to facilitate this, detailing typical expected changetimes for gauge, face and centre cutters.

3.2.5 Wear is to be expected to the surface of the cutter head structure, as well as thebuckets or scrapers. These should be extensively protected with abrasionresisting material (s), which shall have hardness greater than that of the freesilica within the granite matrix. In mechanical terms the hardness shall be equalor greater than that provided by good quality disc cutters (approx Rockwell Rc 55minimum).

3.2.6 A system to detect wear to cutting tools, muck collecting bucket and the maincutter head structure shall be incorporated. A minimum of six wear detectors shall

be provided providing indication in the operators control panel.

3.2.7 The TBM manufacturer is required to carry out a demonstration of the changingof the cutting tools during factory trials. He should simulate how the cutting toolswill be changed in the tunnel by transferring the cutting tools to the material lockand through into the cutter head chamber. Cutters from the centre, middle andperiphery of the cutter head should be removed and exchanged with thosetransported in. The removed cutters are to be transported out. The manufacturershall not use any equipment or working platforms that are not part of the TBMsupply. A full report (written in English and including photographs) is to besubmitted to the Engineer within one month of the demonstration.


7/32



3.2.8 The cutterhead shall incorporate suitable open area to facilitate muck flow.These openings shall be capable of being closed, hydraulically or by manualpositioning of plates in fitted brackets, for safety reasons during interventions in

unstable ground conditions.

3.2.9 Notwithstanding the requirement of clause 3.2.8, openings in the cutterhead shallbe suitable to allow satisfactory access for face inspections, cutterheadmaintenance and occasional manual removal of excavated materials.

3.2.10 Grizzly bars, or other means, shall be provided to prevent boulders of a sizewhich cannot be handled by the spoil disposal system, entering the excavationchamber.

3.2.11 The cutterhead shall have a series of paddles or stirrer bars protruding fromeither the rear face of the cutter-head or from the front face of the shield

bulkhead, or both, that are designed and located to prevent excavated materialplugging within the cutter chamber.

3.3 Cutterhead Drive

3.3.1 The cutterhead shall be driven by a variable speed electric or electro-hydraulicsystem of sufficient power to excavate the anticipated rock and mixed faceconditions at the required rate. A torque/speed curve for the system shall beprovided. The system shall include a facility for starting ‘off load’ prior toaddressing the excavated face. Continual monitoring of cutting torque valuesand main drive motor temperatures shall be provided with interlinks to preset

initial warnings and second stage limit shutdown.

3.3.2 A rapid response torque limiting device shall be installed which shall act toprevent damage to the drive transmission should a cutterhead lockup occur.

3.3.3 The cutterhead drive source and transmission components shall be robust andcapable of completing the contract drive lengths without major overhaul. Themain bearing shall have a design L10 life of 10,000 hours.

3.3.4 The TBM structure shall be so designed so as to allow for the replacement of thecutterhead main bearing and seal assembly from within the tunnel.

3.3.5 The cutterhead main bearing shall be lubricated from a well proven centralisedlubrication system. Strategic sampling points shall be provided to monitorlubricant flows, pressures and quality.

3.3.6 The cutterhead main bearing shall be protected and enclosed by a robust andproven multi-stage seal and labyrinth capable of ensuring internal lubricantintegrity whilst protecting against the ingress of water and excavated fines at themaximum pressure to be encountered which is anticipated to be in excess of 6bar. The system shall be safeguarded against overheating and lack of lubricant.


8/32



3.3.7 The cutterhead shall be fitted with a low speed interlocked inching device capableof rotating the cutterhead under fine control to obtain accurate positioning for thepurpose of face inspection, cutter tool maintenance or probing.

3.4 Shield Body, Propulsion and Tailskin

3.4.1 The circumferential profile of the shield of any TBM supplied by the Contractorshall be built to a tolerance that ensures the tunnel linings can be built to withinthe specified construction tolerance. It shall also be strong enough to avoiddistortion under operational loads during driving and suitable for building thetunnel linings. The design shall take into account, amongst other things, the type,density, gradation, strength and abrasivity of the ground.

3.4.2 The machine shall be fitted with a pressure bulkhead capable of withstanding the

maximum total overburden pressure (including hydrostatic pressure, not less than6 bar), plus an adequate safety margin throughout the life cycle of the TBM withsufficient wear protection to the acceptance of the Engineer.

3.4.3 A minimum of 6 pressure sensors shall be located on the pressure bulkhead (twoat the crown, two at machine axis level and two at the invert) to monitor andrecord the face pressure. Replacement of pressure sensors shall be possiblefrom the rear of the bulkhead without reducing the face pressure. All sensorsshall be calibrated in accordance with the manufacturer’s recommendations.

3.4.4 Recessed into the forward face of the pressure bulkhead shall be an adequatequantity of service penetrations for electricity, water, high pressure air,dewatering or any other facility including spare penetrations, that may be

required that can be manually operated by maintenance personnel who may bein front of the pressure bulkhead. The recesses shall have a cover to ensure theingress of tunnel spoil does not occur. All services shall be suitably designed foruse during compressed air works.

3.4.5 The TBM shall be articulated to allow for steering along the specified alignment.Articulation joints shall be provided with a sealing arrangement capable ofwithstanding the full hydrostatic head and full overburden pressure. Seals shallbe protected from damage caused by ingress of material during the activation ofthe shield articulation. Articulation rams shall be fitted with a mechanism to resisttorque resistance.

3.4.6 At each articulation joint there shall be a sufficient number of lubrication injectionpoints to the external portion of the shield structure. A non return valve shall beconnected to each injection point to arrest the flow of material from outside theshield.

3.4.7 The TBM shall include a series of ports in the shield skin to facilitate thelubrication of the shield/ground interface around the entire periphery of the shield.The distribution system should be located as near to the cutterhead as practicaland should be fitted with non-return valves to prevent ingress of ground.


9/32



3.4.8 The TBM shall be equipped with thrust rams of sufficient capacity to advance themachine through all materials encountered at full hydrostatic pressure at a ratecommensurate with the progress rate required by the programme.

3.4.9 Thrust cylinders shall be arranged such that individual rams can be operatedindependently during ring building, or in groups for the purpose of steering theshield. The hydraulic pressure shall be independently variable in each group fromthe operator console.

3.4.10 Rams shall be fitted with shoes made from hardwood, polyurethane or similarmaterial and so arranged that the line of action is through the middle third of thesegment. The shoes shall be dimensioned such that the bearing load does notexceed that permissible for the segments.

3.4.11 The tailskin shall be fitted with a minimum of three rows of wire brush tail seals,but preferably four rows in view of the high water head, to prevent the ingress of

water and/or grout between the tailskin and tunnel lining. The tail seal assemblyshall be capable of withstanding the full hydrostatic head and exclude the ingressof any grout being injected. At least two rows of the wire brush tail seal elementsshall be replaceable from within the shield without exposing the ground during thedrive. An effective tail seal greasing system shall be provided to lubricate the tailseals continuously from an automatic variable flow and pressure system.

3.4.12 Grout excluder plates shall be fitted to the outer end of the tailskin to preventgrout migration along the shield towards the face.

3.4.13 The machine shall be designed to enable the void behind the segments to be

grouted continuously and completely from the shield as it is propelled forwardthrough grout ports incorporated within the tailskin. These shall not be mountedexternally on the machine.

3.4.14 There shall be at least one set of grout ports in each quadrant of the tailskincircumference, preferably located at or close to the tunnel shoulder and kneelevels. The machine shall have the facility and the capacity to inject groutsimultaneously through at least one grout port in each quadrant.

3.4.15 The grout injection ports should be suitable for the injection of two componentgrouts, and the design in each quadrant should incorporate facilities for flushingthe ports and mechanical cleaning. In addition, its design should enable the grout

pipes to any individual port to be cleaned or replaced from within the shield in theevent of a blockage without impairing the performance or preventing the use ofany other grout port.

3.4.16 Spare ports should be incorporated to ensure that at least one grout port in eachquadrant of the shield shall be operational and available for grouting at all timesduring shield advancement.

3.4.17 Grout pressure and flow rates shall be maintained at all times whilst the shield isadvancing. Pressure shall be measured at the point of injection. The TBM shall


10/32



incorporate automatic systems for monitoring, controlling and recording thevolume and pressure of the grout being delivered to the tail void.

3.4.18 The machine shall have an anti-roll device details of which shall be accepted by

the Engineer prior to the commencement of tunnelling works.

3.4.19 The machine design shall permit removal back to the launch shaft of the machinefrom within the shield, which may be left in place at the completion of the tunneldrive.

3.5 Compressed Air Provision

3.5.1 Cutterhead interventions will be necessary on a regular basis for the purpose ofcutterhead inspection and maintenance and for cutter changing. Some of theseinterventions may be in conditions where the hydrostatic water head above the

crown of the TBM is above 40 metres. In view of the fact that current regulationslimit the use of compressed air to 3.5 bar, the Contractor shall submit his methodof statement for the Engineer review and acceptance prior to such interventionbeing carried out. The method of statement may include any, or a combination ofthe following:1. Ensuring that the TBM stops in an area of treated ground2. Complete or partial treatment of the ground to minimise ground water flow

combined with lower compressed air pressures3. Application to the Commissioner for Workplace Safety and Health for

exemption in order to utilise pressures higher than 3.5 bar4. Only partial emptying of the face to reduce the air pressure required5. Allowing minimal seepage from the face to facilitate the use of lower

pressures. This would require pumping capability within the TBM

6. In extreme situations saturation diving techniques may be required forprolonged entries at higher pressures.

To facilitate any or all of these techniques the TBM should include the followingfeatures.

• Airlocks – see clauses 3.5.2. to 3.5.5.

• Probing and drilling arrangements – see clauses 3.6.1 to 3.6.4.

• Provision for adequate platforms in the cutterhead chamber – see clause3.2.7.

• Provision for adequate pumping and dewatering from the TBM – see clause3.1.5.

3.5.2 All airlocks shall conform to BS EN 12110:2002 or equivalent internationalstandard. See also requirements of clause 9.2 below.

3.5.3 The TBM shall incorporate a twin air-lock each with two compartments for manaccess to the cutterhead and face, with the main compartment sized for at least 3persons. The air lock should be designed to suit the maximum interventionpressure, consistent with the alignment and depth selected by thecontractor. The contractor should state in his offer the pressure for which theairlock will be designed. If this pressure is in excess of 6 bars, the requirementsof Clause 3.5.6 will apply. The inner compartment shall be able to accommodate


11/32



a 1.8-metre long stretcher and two attendants. Doors shall be capable of beingopened without manipulation of the stretcher and patient.

3.5.4 The airlocks shall be fitted with all the necessary provisions to enable

decompression using oxygen or mixed gas mixtures (e.g. Heliox, Nitrox or Trimix)to be employed. Refer to the documents mentioned in Clause 9.2.3.

3.5.5 A material lock shall also be provided independently of the personnel air locksand this shall be located at a convenient point above horizontal axis for thetransport of maintenance tools and disc cutters etc. into the pressure chamber.

3.5.6 If the Contractor includes saturation diving techniques as one of his contingencyproposals for interventions or access to the cutterhead when tunnelling at thedeep level, the air lock should be manufactured with an outer flange around theaccess door opening to enable a “Transfer under Pressure (TUP) Shuttle” tocouple safely to the lock and allow transfer of personnel at pressure. If suchprocedures are considered possible, a fully detailed method statement, following

the principles laid down in the document listed in Clause 9.2.4 is to be agreedwith the Engineer.

3.6 Probing and Ground Treatment

3.6.1 The machine shall be designed for and equipped with a supplemental groundstabilisation system. The machine shall be designed to allow forward drillingthrough the cutterhead and shield for the purpose of probing ground conditions tocarry out ground treatment to the face and surrounding ground. The proposedsystem shall comprise of regularly spaced grout sleeve pipes built into the shieldskin for grouting the ground ahead of the tunnel axis. They shall be fitted with

suitable valves and located such that there is space for the use of blow outpreventers. This system shall comprise a minimum of 16 No regularly spacedgrout sleeve pipes built into the shield skin for grouting the ground ahead of thetunnel face. They shall be inclined at an angle of approx 5º from the tunnel axisand be fitted with suitable valves and located such that there is space for the useof blow out preventers.

3.6.2 In addition provision for drilling straight ahead through the bulkhead andcutterhead shall be provided.

3.6.3 These access ports may be used for ground stabilisation around or ahead of theTBM or for probe drilling. The capability to recover 38mm rock cores should beprovided.

3.6.4 Ground stabilisation ahead of the TBM is considered an important tool in view ofthe depth of the tunnel and the geological conditions. A minimum of two drillingmachines capable of probing or drilling for ground treatment shall be providedeither on the TBM or close behind on the back up gantries. They should becapable of drilling a minimum of 50 metres ahead of the face and kept in workingorder at all times. The drilling/grouting equipment shall be permanently mountedin the machine and be operational within 2 hours of any requirement to drill/grout.


12/32



3.7 Erector

3.7.1 The machine shall be equipped with a tunnel lining erector system capable ofplacing each lining segment safely into its final position along the periphery of the

ring being erected. The erector and the tail skin / seal configuration shall bearranged such that damaged segments are capable of being removed from anassembled ring within the first 500mm of the TBM advance.

3.7.2 The erector shall be controlled from a radio controlled pendant such that theoperator has a clear unobstructed view of all of the plant that he is operating at alltimes. During ring building the controls for the shield rams shall be transferredfrom the TBM operator cabin to this pendant.

3.7.3 The erector shall be provided with the facility to lower the segment from top deadcentre to bottom dead centre location, for safety, in the event of mains powerfailure whilst ring erection is in progress.

3.7.4 Ladders and platforms fitted with toe boards and safety harness connectionsshall be provided to enable operatives to reach bolt connection holes. Platformsshall be fitted with appropriate safety systems to prevent collision with theerector.

3.7.5 The segment erector and segment feeder shall be fitted with audible and visualalarms that activate prior to movement.

3.7.6 If a vacuum type lifting pad is proposed, design calculation shall assume 80%vacuum for all vacuum devices. Mechanical shear pins shall be incorporated intothe design. In the event of power failure, the vacuum system shall be able to

hold the heaviest segment for 20 minutes.

4. PARTICULAR REQUIREMENTS FOR SLURRY MACHINES

4.1 General

4.1.1 Slurry TBM’s operating in fractured and weathered rock may suffer from excessblockages within the cutter head and in the pipework. The contractor shouldprovide a method statement of how such blockages will be minimised andcleared when they do occur.

4.1.2 Slurry inlet pipes shall be arranged to enable jetting near the invert to preventsettling of material and to act in conjunction with the stirrer bars mentioned in3.2.11 to minimise blockages.

4.1.3 Control of face pressure in the slurry should be within ± 0.1 bar at all times. Anyfluctuation in pressure beyond this limit shall initiate an audible and visual alarmin the TBM operator’s cabin and both the Contractors’ tunnel office at the surfaceand the Engineer’s office. The slurry seal in the slurry chamber shall have a


13/32



structure capable of withstanding a slurry pressure that is at least three (3) timesthe maximum planned face pressure.

4.1.4 The Contractor shall ensure that the spoil transportation system and other

support services to the TBMs have sufficient capacity to ensure that the proposedTBM tunnelling rates can be maintained in all the anticipated ground conditions toachieve the programme key dates and meet the Schedule of Timing.

4.1.5 Experience show efficient slurry discharge reduces blockages in the cutter headchamber increasing efficiency and reducing unplanned interventions. TheContractor is advised to pay special attention to the routing of the slurrytransportation pipe work to reduce unnecessary bends through the TBM.Location of primary pumps and crushers should be selected to improve theefficiency.

4.1.6 The positions at which the slurry feed and, discharge pipes are mounted on thebulkhead shall be determined in consideration of the slurry flow within the slurry

chamber and discharge of the excavated soil. Slurry discharge pipes shall beprovided in two or more locations as a precaution against blockage.

4.1.7 An agitator shall be attached at the bottom of the slurry chamber to prevent soilfrom settling while not excavating.

4.2 Slurry Circulation

4.2.1 Design of the slurry circulation and control system should take into account, interalia, properties of the excavated material and the properties of the required slurryto be pumped to the TBM. Flows, velocities and consequent pipe sizes and

slurry densities shall be designed to maintain suspension and minimisesettlement whilst minimising abrasion and power consumption. The Contractorshall supply calculations supporting his design.

4.2.2 Slurry pipework on the TBM shall be arranged to optimise the slurry flow throughthe excavation chamber, and to minimise clogging at the discharge entrance.Provision shall be made to break up balls of clay or other fine materials beforethey enter the discharge pipes.

4.2.3 The TBM shall be capable of preventing any over pressurisation of slurry in thecutter head chamber by automatically cutting off the slurry feed and initiating apressure release valve to restore the pressure to that specified.

4.2.4 It is anticipated that some large pieces of rock may enter the cutterheadchamber. The Contractor shall indicate how these would be dealt with. A rockcrusher shall be incorporated into the circuit in order to break down largeboulders and assist their passage through the pipes and pumps.

4.2.5 The rock crusher shall have sufficient capacity to crush any boulders, withoutimpeding the advance of the machine. It shall be arranged so that it can berepaired and maintained during the drive.


14/32



4.2.6 The slurry circulation circuit must incorporate a bypass close to the TBM so thatsteady circulation can be established before the slurry is allowed to enter theTBM. Bypass lines on the surface and at the shaft bottom shall also be includedin the circuit.

4.2.7 Facilities to reverse circulate the slurry flow in the pipework close to the TBMshall be included in order to assist the clearing of blockages. Alternative slurrysupply pipes to the cutterhead chamber shall be fitted including jetting nozzles, toenable blockages and clogging to be minimised and mixing of spoil in thechamber to be optimised.

4.2.8 Slurry pipes shall extend as the TBM and backup system advance. It is foreseenthat this is by means of telescopic pipes or flexible hoses situated at the rear endof the backup system. Adequate means of supporting and operating these,including the storage of additional pipe lengths and the placement of gate valvesat regular intervals shall be provided.

4.2.9 High vibrations and movement of discharge pipes shall be avoided. The pipesshall be anchored sufficiently to avoid the risk of rupture.

4.2.10 Booster pumps shall be installed along the tunnel at suitable locations to ensureoptimum slurry flow rate. A minimum of one spare booster pump for each tunneltogether with all associated valves and controls shall be kept at site.

4.2.11 Pipes shall be installed without loss of pressure in the face and with the minimumloss of slurry into the tunnel. A means of collecting and disposing of all slurryspilled during the pipe extensions shall be provided.

4.2.12 Pipe work shall wherever possible be laid in straight runs to minimise friction

losses and wear. Where bends are unavoidable, these shall be heavilyreinforced to provide extra wear protection, and be easily replaceable. Pipe workshould be thick walled and have its thickness checked regularly by the contractor,who should also periodically rotate straight lengths of pipe.

4.2.13 Wear due to abrasion in the discharge pipe and components is expected to behigh. Abrasion resistant materials should be used wherever practicable. All pipe joints shall be of the raised flange “S-type” so there is no reduction in wallthickness along the length of the pipe. Recessed flange “G-type” pipe joints shallnot be used.

4.2.14 Flow meters and density meters shall be provided on both supply and discharge

pipelines to enable the total quantity (flow rate and density) of solids excavated tobe monitored and recorded continuously while the TBM is cutting at the face.

4.2.15 The machine design shall make provision for the crusher to be checked at thestart of each shift and cleaned where appropriate.

4.2.16 The slurry feed and discharge pipes shall be controlled so that the flow volumeand pressure can be adjusted before and after cutting, to ensure the stability ofthe face.


15/32



4.2.17 The slurry transportation system shall include a facility that links the slurrypressure sensors and the slurry feed and discharge pump, to allow a constantslurry pressure to be maintained at the cutting face. There shall be a facility thatautomatically adjusts the pressure when fluctuations in the slurry pressure at the

cutting face are detected.

4.2.18 Gate valves shall be installed at regular intervals along both the feed anddischarge slurry pipes.

4.2.19 The pressure control system shall be relayed to a monitor on the surface forcontinuous monitoring. Provision shall be made to enable pressure to be adjustedfrom the surface at times when the machine is not operating.

4.3 Slurry Treatment Plant

4.3.1 The Slurry Treatment Plant (STP) is deemed an integral part of the slurry TBMdesign. The Contractor shall include in his TBM design submission full details ofhis proposed STP, together with details of the slurry pumps and pipelines.

4.3.2 The slurry treatment plant (STP) and its support system shall be designed byspecialists with experience in the operation of this type of equipment and thedesign shall be endorsed by the TBM manufacturer. The design shall clearlydemonstrate:

a) Operation and control of the slurry treatment plant in conjunction with theTBM as one complete system;

b) Consideration of the planned efficiency of separation of each stage (e.g.primary, secondary, fines) of the separation process and the particle sizegrade separation at each stage to suit the anticipated ground conditions.This shall be specified in terms of weight of dry material processed perhour and the plant operational efficiency, which shall be based on pastexperience and not be taken as 100%;

c) The ability to provide slurry at the required density for circulation to theTBM;

d) Compliance of the STP with the statutory requirements for noise andvibration.

4.3.3 The STP shall have sufficient capacity for all stages of treatment to match theprogrammed advance rates for all the TBMs excavating through the mostonerous anticipated ground conditions without causing any delays to theadvancing TBMs. The plant shall be designed to facilitate routine maintenancewithout requiring TBM advance to halt and shall be capable of being expanded toincrease operational capacity should the need arise. Such expansion or anyadditions or modifications to the STP shall be approved by the STP supplier andaccepted by the Engineer.


16/32



4.3.4 Slurry treatment is required to have sufficient holding tank capacity to meet therequirements for each TBM. This capacity includes sufficient capacity for slurry /water being treated before discharge into the public drains as well as sufficientcapacity for holding of fresh hydrated bentonite. For avoidance of doubt, holding

and mixing tanks shall be separate.

4.3.5 The STP shall be monitored and controlled from a central control cabin whichshall as a minimum have a direct telephone line to the TBM control cabin for thesole use of the TBM operator and STP plant operator. The STP central controlcabin shall be connected to the TBM slurry circuit monitoring system with asuitable display acceptable to the Engineer. The STP operator shall be capableof controlling all aspects of the work from within the control cabin including thetransportation and treatment of the slurry.

4.3.6 All STP main components shall be monitored real time with visualization and dataacquisition in the STP control room and the Engineer’s office. Information to be

monitored and recorded is, inter alia,

• Flows into and through the separation plant (t/hr)

• Weight (t) and volume of solids removed (m3)

• Volumes of fresh slurry added to the system (m3)• Volumes of slurry transferred to secondary treatment (m3)

• Amount of flocculent used

• Weight of solids and water recovered from secondary treatment andremoved (t)

• Levels of active and storage tanks (m)• Density of slurry in the active tank (t/m3)

The system shall produce a printed report to be submitted to the Engineer daily.

4.3.7 It is envisaged that one central control room for monitoring both the TBMoperating parameters and the STP parameters will be established in theContractor’s office. This will allow for the proper control and integration of the two(2) critical systems.

4.3.8 The STP shall be suitably designed with testing points so that-routine testing atvarious stages of separation can be safely and easily carried out with minimumtime.

4.3.9 A test laboratory shall be included as part of the surface installation. This shallhave equipment for measuring density, and sand content of slurries, apparentand plastic viscosities, together with the yield point of slurries, gel strengths, pHlevels, filter cake formation, fissure penetration and other routine slurry tests.

4.3.10 Slurry supplied to the TBM from the treatment plant shall have a density to suitthe prevailing ground conditions being excavated. The density of the slurrysupplied to the TBM shall never be greater than 1.15 and the STP should havecapacity to remove sufficient material to ensure that this density can be


17/32



maintained without impairing the advance rate of the TBM in all groundconditions.

4.3.11 The transportation of the discharged spoil away from the work site shall be by

means that prevents spillage in either fluid or solid form. The Contractor shallassess the traffic conditions and the impact to the existing transportation system.Measurement of the amount of spoil shall be carried out by the Contractor.

4.3.12 Slurry and other water discharged from the works shall be passed throughfiltering facilities before being discharged. Any filtered water that is dischargedinto water courses or sewers shall be in accordance with the relevant SingaporeRegulations and Standards.

4.3.13 Noise from STP operation and spoil removal activities may be excessive and cancause inconvenience to residents in nearby buildings. The Contractor shallcomply with the NEA regulation on noise control (refer to General Specification).If necessary, the Contractor shall provide full acoustic enclosures/barriers overand around STP and muck-pit areas to contain the noise and preventdisturbance.

4.3.14 The STP shall be suitably designed and operated in a manner to ensure that aslurry density appropriate to the prevailing ground conditions is continuouslysupplied to each TBM. The TBM operator shall be provided with a CCTV link toenable him to observe the STP primary screens for the effects of variation in TBMpenetration and cutter head speeds and to ensure maximum primary screenseparation.

4.3.15 The STP and TBM monitoring systems are to be compatible to allow the overallcontrol of slurry volume in the active circuit for each TBM. The real time volume is

to be displayed on the STP visualization, data logged and linked to an alarm tobe activated if the volume varies by more than a predetermined value agreed withthe Engineer.

4.3.16 Materials separated at primary, secondary and final stages of separation are tobe segregated prior to removal from site in bins to facilitate identification of achange in ground conditions.

4.3.17 Slurry feed and discharge density shall be monitored as near to the TBM cutterhead as possible as well as at all appropriate separation stages of the STP.


18/32



5. PARTICULAR REQUIREMENTS FOR EPB MACHINES

5.1 General

5.1.1 The EPB TBM’s shall be equipped with a rotary joint to supply soil conditioningmaterials to the cutterhead, a screw conveyor and a belt conveyor for muckdisposal.

5.1.2 Belt conveyors shall be fitted with scrapers and be suitable for wet, abrasive andsticky material. Conveyor belting shall be heavy duty, suitable for undergrounduse and made from materials which reduce the fire risk and toxic fume risk

5.1.3 The conveyor belt shall incorporate an automatic material weighing system tomeasure the weight of material excavated on a continuous basis. Thisinformation to be recorded in the TBM data logging system.

5.2 Screw Conveyor

5.2.1 The screw conveyor shall be of a sufficient length to allow for adequate pressuredissipation along its length whilst maintaining an effective plug to balance theground and ground water pressures that will be encountered.

5.2.2 Calculations with supporting analysis shall be provided with the final designsubmission to demonstrate that the capacity, power and length of the screwconveyor is sufficient.

5.2.3 The discharge of the screw conveyor shall be installed with a closing mechanism

that can withstand a pressure of at least 25% greater than the maximumexpected head of water. It shall be fitted with an accumulator which automaticallycloses the gate in the event of a power failure or when the face pressure fallsbelow a pre-set value.

5.2.4 The screw conveyor shall be capable of being withdrawn and a water tightguillotine gate closed on the bulkhead to allow maintenance without loss of facepressure.

5.2.5 To protect against excessive abrasion, replaceable abrasion resistant wear partsshall be fitted at the entrance to the screw conveyor casing and on the tips of thefirst three pitches of flights.

5.2.6 The screw casing shall be fitted with injection points for conditioning agents andwith earth pressure monitoring cells.


19/32



5.3 Soil Conditioning

5.3.1 The machine shall be equipped with a suitable soil conditioning system tocondition the material as it is excavated. It should be capable of supplying

bentonite, foam and polymers to the cutterhead and to the bulkhead and screwconveyor during excavation.

5.3.2 There shall be a sufficient number of injection ports in the cutterhead, spacedproportionately to the swept area, to inject the additives. Each port shall have itsown individual feed line through a rotary coupler, and fed from independent foamgeneration units. Provisions should be included for clearing or replacing anyblocked lines and/or ports from inside the TBM.

5.3.3 The operation and control of the soil conditioning plant shall be from within theTBM operator panel and volumes and pressures of additives injected shall bemonitored and recorded.

5.3.4 The calculations and detailed design of the soil conditioning system shall beprovided during the design stage of the TBM supply.

6. BACKUP SLEDGES

6.1 General Requirements

6.1.1 A high degree of wear is to be expected for the material transport system. Allcomponents designed to transport the excavated material shall be manufactured

to provide an abrasion resistant surface to minimise replacement and / ormaintenance.

6.1.2 The towing load in the connection between the TBM and the trailing backup shallbe continuously monitored. When the tow force exceeds 110% of the maximumdesigned tow force an audible/visual alarm shall be activated in the TBMoperator’s cabin. When the towing load reaches 120% of the designed tow forcethe thrust ram pump shall be deactivated automatically to prevent the TBM fromadvancing further.

6.1.3 A physical barrier shall also be located at the last TBM trailer to separate andprotect the workers in the shield from moving railway equipment. The barriershould be in position at all times and be raised manually by the loco driver whena train wishes to enter the TBM backup.

6.1.4 Adequate facilities shall be provided for the extension of all services to the TBMat the rear end of the last trailer.

6.1.5 Design of the backup trailers shall allow for them to be removed at the end of thedrive by withdrawing back along the constructed tunnel.

6.1.6 There shall be a clear and unimpeded means of egress along the full length ofthe back up at all times from the erector to the tunnel walkway.


20/32



7. ALIGNMENT CONTROL

7.1 General

7.1.1 For general survey requirements for tunnelling works refer to M&W Specification.

7.2 TBM Guidance Control

7.2.1 A suitable and proven guidance system shall be installed on the TBM to providethe necessary survey data and lining erection information for accurate control andsteering of the machine.

7.2.2 A tunnel machine guidance system is mandatory. The machine shall not advancewithout a fully operational guidance system.

7.2.3 The guidance system shall produce a comprehensive real time read out of thecurrent shield position and attitude and of the predicted position at a set distanceahead. The system shall incorporate a laser theodolite, distomat and thenecessary laser target, mounting beam etc. which shall form an integral part ofthe TBM. Monitoring information from the TBM guidance system shall be visiblein the TBM operators control cabin and in the in the Engineers office on thesurface. All data is to be recorded digitally for submittal to the Engineer both as ahard and electronic copy.

7.2.4 Prior to the commencement of tunnelling and then throughout the tunnel drive theContractor shall establish and implement survey and alignment controlprocedures. During each shift the Contractor shall survey the position of the

tunnelling machine and verify the guidance system readout is correct.

7.2.5 The fully integrated system shall comprise at least, measuring equipment,software, PC and display. The design tunnel alignment entered into the systemshall be password protected. The display shall be updated every few secondsand provide the operator with the necessary graphical and numerical information.The system shall compute the precise machine position and offsets from the“Design Tunnel Alignment (DTA)”. The following information shall be displayed:a) Cumulative ring number from start of drive;b) Chainage;c) Pitch and roll;d) Look up (plumb to DTA);

e) Lead (square to DTA);f) Line and level;g) Prediction of shield position at 10 meters ahead of current position;h) Articulation angle (where applicable).

The guidance system shall be capable of determining the 3D coordinatedposition of the tunnel machine from the proven survey control in the tunnel to anaccuracy of ±2mm. All guidance system parameters, input, output and reportsshall be made available to the Engineer in softcopy format (e.g. Excel or similar).


21/32



8. ELECTRICAL SPECIFICATION


8.1.1 Electrical equipment shall conform to the following standards

• BS 6164:2001 Code of Practice for safety in tunnelling in the constructionindustry.

• BS EN 12336:2005 Tunnelling machines. Shield machines, thrust boringmachines, auger boring machines, lining erection equipment. Safetyrequirements.

• 1989 Electricity at Work Regulations taking into account Mines Regulationssection where applicable.

• The BS 7671: 2008 IEE Wiring Regulations – Regulations for ElectricalInstallations, 17th Edition

• BS 5304:2005 Safety of Machinery.

• BS 7430: 1998. Earthing.

• BS EN 60204:2006 Electrical Equipment for industrial M/Cs.

• BS 7375: 2010 Distribution of Electricity on Construction sites.

• Other relevant BS Standards for equipment, workmanship and testing

• Singapore Standards CP5 and CP16 as appropriate

• Workplace Safety and Health (Construction) Regulations 2007, Part V,Electrical Safety

8.1.2 All cable shall be LSOH type. PVC cables shall not be permitted.

8.1.3 Pilot and earth monitoring of power supply cables shall be required.

8.1.4 All backup trailers shall be securely bonded together with an earth link whichshall not be smaller than the largest current carrying conductor.

8.1.5 Power factor correction equipment shall be installed to ensure a minimum PF of0.9 lagging.

8.1.6 All electrical enclosures shall be protected to IP55 as defined in BS EN 60529.Where this is not practical, for example in the case of power transformers, a lowerIP rating may be used provided the enclosure is in turn contained within apressurised cabinet providing adequate additional protection.

8.1.7 Gland entry to enclosures shall be bottom entry. Where this is impractical andside entry is used, a water cover must be fitted. Top entry shall not be permitted.


22/32



8.2 Controls and Instrumentation

8.2.1 The machine shall be equipped with an air-conditioned control cabin. Themonitoring and control instrumentation shall be grouped in suitable panels within

the control cabin. The cabin shall be smoke/fire proof.

8.2.2 The criteria that shall be monitored and available for the TBM operator to accessin the control cabin shall include, but not be limited to, the following data. It shallalso be available on the data logging system.

a) Start and finish time of the excavation stroke;b) Start and finish time of the ring erector operation;c) Shield position and attitude for each ring;d) Stroke number, chainage and guidance system’s predicted of the next ten

strokes after each build;e) Rate of advance of TBM and stroke average rate of advance;f) Numbers of thrust cylinders, location and pressures used during the stroke;

g) Extensometer readings of thrust cylinders at the start and end of the stroke;h) Articulation cylinder position at the start and the end of the excavation stroke

(articulation angle);i) Amount of TBM roll at start and end of the excavation stroke; j) Cutting direction, rotation speed, and pressure/torque of cutterhead;k) Main bearing axial force;l) Main bearing lubrication temperature monitored at exit point if re-circulatory

oil, or thermocouple against bearing if grease lubricated;m) Electrical current consumed by each TBM motor;n) All earth pressure sensor readings throughout the excavation stroke for cutter

chamber;o) Volume and pressure of grout injected per stroke (pressure shall be

measured at the point of injection. Pressure and volume shall be monitored

and recorded to an accuracy of not less than two decimal places);p) Quantity of tail grease consumed per shift;q) Gas detector sensor readings and alarm activation system;

For EPB Machines

a) Volume, rate of addition, type and location of soil conditioning added per ringand the cumulative amount per shift with the concentration value;

b) Speed and torque of screw conveyor ;c) Earth Pressure in the screw conveyor;d) Volume and mass of material on the belt ;

For Slurry Machinesa) Display and adjustment of the slurry pressure at the cutting face;b) Display and adjustment of the feed slurry pressure;c) Display and adjustment of the feed, and discharge slurry flow volume;d) Display of the feed and discharge slurry density;e) Volume of materials excavated per ring of advance;f) Display of feed and discharge slurry pump operating conditions;g) Volume of slurry leakage when the machine is stationery.


23/32



8.2.3 The data logger shall be linked to a colour monitor display in the Engineer’soffice. Each machine shall have its own dedicated colour monitor. The datalogger shall display and record information in real time and shall have the facilityto store all accumulated data from the tunnel drive and to read and display past

data. All data loggers and ancillary equipment shall be provided by andmaintained fully operational throughout the drive by the Contractor. Each datalogger computer shall be connected to a colour printer. The Contractor shallprovide all necessary peripherals and consumables necessary for the display andprintouts. The display monitor(s) and printer(s) shall be sited in the Engineer’soffice. All data loggers and ancillary equipment shall be fully operational at alltimes and shall, be maintained by the Contractor.

The information on the data logger, which is available to the Engineer’s Officesystem, shall be made available on a secured website for Engineer monitoringpurposes.

8.2.4 The machine shall be equipped with acceptable device or devices from which the

weight and volume of material excavated can be monitored and recordedautomatically in real time. These shall be located where they are least affected byvibration, roll and tunnel curvature. The device shall be synchronized with theexcavation cycle such that it is only activated when the TBM is excavating. Themeasured quantity shall be displayed in the control cabin and in the Engineer’soffice, both on a ring by ring basis and as a rolling 10 ring average. An audibleand visual alarm shall be incorporated in the control cabin which shall beactivated if the measured volume exceeds a pre-determined quantity related tomachine advance.

9. SAFETY

9.1 Regulations

9.1.1 The design and manufacture of the TBM and back-up systems shall makeadequate provision for the safety of the workmen and the application of safemethods of tunnelling and shall comply with all relevant British, European and/orSingapore Standards and Codes of Practice relating to safety including, but notlimited to:-

a. BS 6164: 2001 Code of Practice for Safety in Tunnelling in the ConstructionIndustry;

b. BS EN 12336: 2005 Tunnelling Machines - Safety Requirements;

c. BS EN 12110: 2002 Tunnelling Machines-Air Locks-Safety Requirements.

9.2 Work in Compressed Air

9.2.1 It is envisaged that the TBM personnel will work in compressed air conditionsduring cutter head intervention. Working in compressed air poses occupationalhealth and safety risks. Only competent personnel shall be permitted to workunder compressed. In addition, the “Workplace Safety and Health Guidelines for


24/32



Compressed Air Works”, 2010, published by the Workplace Safety and HealthCouncil shall apply.

9.2.2 See also the requirements of Clause 3.5.

9.2.3 For working in Compressed Air the following documents and guidelines should befollowed:

a. The Work in Compressed Air Regulations 1996(UK);

b. HSE L96 A Guide to the Working in Compressed Air regulations (1996) (UK);

c. An addendum to "A guide to the Work in Compressed Air Regulations 1996"giving “Guidance on OXYGEN DECOMPRESSION and the use of BreathingMixtures other than Compressed Natural Air in the Working Chamber”.

d. Workplace Safety and Health (Construction) Regulation 2007

9.2.4 In addition to the above, for working in pressures above 3.5 bar, the following

document is currently being prepared jointly by International TunnellingAssociation and the British Tunnelling Society

• ‘Guidelines for Good Working Practice in High Pressure Compressed Air’

This should be available by the end of 2011 and shall be followed as appropriate.

9.3 Fire Prevention

9.3.1 Provision shall be made throughout the length of the TBM and back-upequipment for the detection and suppression of fires. This shall include

• Automatic fire detection to sound an alarm in the TBM operators cabin

and on the back up• Manually operated sprinkler system for foam or powder over high risk

areas such as hydraulic power packs;

• Automatic operation of inert gas suppression to electrical cabinets;• Hand held extinguishers provided with colour coded covers in suitable

locations;• The provision of a water curtain sited at the trailing end of the TBM

backup.

9.3.2 The fire prevention system shall be maintained in an efficient operating conditionat all times.

9.4 Environmental Monitoring

9.4.1 All TBMs shall be equipped with gas monitoring sensors, which shall be locatedat appropriate locations along the TBM including the screw conveyor dischargeon EPB machines, slurry pipe extension area on Slurry TBM’s, the TBM bulkheadand the ring building area on all machines. All sensors shall be connected to anaudible/visual alarm system located throughout the tunnel and at the surface.The sensors should detect potentially hazardous gases including but not limitedto oxygen deficiency, methane, carbon dioxide and carbon monoxide. In addition


25/32



the gases NOx and H2S should also be monitored if it is considered there is a riskof them being present.

9.4.2 The alarm shall automatically activate at gas levels exceeding the permissible

exposure levels as defined in the Workplace Safety and Health (Construction)Regulations 2007 and BS 6164: 2001 Code of Practice for Safety in Tunnelling inthe Construction Industry.


9.5.1 The Contractor shall use synthetic hydrochloric fire resistant (type HFDU) fluidson all systems of the machine and back-up equipment so as to minimise the riskof an oil fire.

9.5.2 Sufficient, non slip foot steps and safety harness attaching points adjacent to alllocations in the cutterhead where cutter changing may occur shall be provided toensure personnel are adequately protected. Either a mechanical device tosupport the mass of any cutter assembly greater than 30 kg, or attachmentpoints, for personnel to connect hand operated lifting devices shall be provided.

9.5.3 The material used for any conveyor belting used shall be non-combustible andlow smoke emission type.

9.5.4 All moving machinery installed on the TBM shall be appropriately guarded. Guarddesign should allow for routine maintenance requirements. Audible/visualmovement warning signals shall be installed together with an emergency stopsystem at locations to be agreed with the Engineer. The conveyor beltemergency isolation system shall include pull-wire interruption along the entirelength and on both sides of the belt.

9.5.5 The Contractor’s support services shall be compatible with the design of theTBMs (Contractor shall obtain the endorsement of machine supplier), its intendedspoil handling system and the ring erecting system to ensure that work can becarried out efficiently and safely.

10. MANUFACTURING & COMMISSIONING

10.1 General

10.1.1 Before the machine is dispatched to the tunnelling site, it shall be completelyassembled in the manufacturer’s factory with all necessary equipment installedso that it is in working order for inspection and checking by the Engineer. Samplesegments shall be available to demonstrate the segment erection procedure. Theassembled TBM shall be tested and commissioned before shipment to site.

10.1.2 The Contractor shall supply all necessary information to the Engineer, including aprogramme of manufacture and testing, to enable him to inspect the machine at


26/32



the manufacturer’s factory to ensure that the design and manufacture are inaccordance with the specification and to enable him to observe the factory tests.The Contractor will be given one week notice of any visits required and he shallensure that suitable English speaking technical staff from either the Contractor or

his TBM supplier are available to accompany the Engineer and hisrepresentatives.

10.1.3 A complete list of spare parts, wear items and consumables shall beestablished for the TBM and be submitted to the Engineer prior to Testing of theTBM in the factory.

11. TBM OPERATION & USE

11.1 General

11.1.1 The Contractor’s support services shall be compatible with the design of theTBMs, its intended spoil handling system and the ring erection system to ensurethat the work can be carried out efficiently and safely.

11.2 Assembly and Erection

11.2.1 When delivered to site the machine shall be erected in the launch chamber orstart shaft to the required grade and line, and to maximum tolerances of ± 6 mmin external diameter and ± 20 mm in external circumference or as specified by themanufacturer.

11.2.2 Details of the TBM erection and procedures for launching the TBM from theunderground launch chamber shall be provided to the Engineer.

11.2.3 The design of the TBM and thrust frame together with the support frame for thetemporary shove rings shall be carried out by a Professional Engineer (PE)registered with the Professional Engineers Board and shall be submitted to theEngineer for acceptance. The TBM cradle, thrust frame and support frame for thetemporary shove rings shall be inspected and endorsed by the PE prior to loadingand unloading.

11.2.4 A detailed method statement shall be submitted for acceptance prior to the

installation and removal of the TBM cradle, thrust frame and the support frame forthe temporary shove rings.

11.3 Operation and Maintenance

11.3.1 The Contractor shall operate and maintain the machine to the satisfaction of theEngineer and in accordance with the manufacturer’s recommended operatingand maintenance instructions.


27/32



11.3.2 The Contractor shall store on site critical replacement parts and maintenancematerials, to ensure that the TBM is not delayed waiting for delivery ofcomponents. The Contractor should submit to the Engineer a list of such

components that will be stored on site, and these should include (but not belimited to) such items as

a) Sufficient complete sets of discs, picks, cutters and scrapersb) Nonstandard hydraulic rams, hydraulic hoses and componentsc) One spare PLC card for each electronic componentd) Other electrical consumable componentse) One full set of tail seal brushesf) One full set of earth/fluid pressure sensorsg) Spare impellors and casings for slurry pumps (for slurry TBM)h) Screens and cyclone spigots for STP(for slurry TBM)i) Conveyor belting, rollers, bearings and bolts (for EPB TBM) j) Wear components for Screw conveyor(for EPB TBM)

11.3.3 The TBM operators and the Contractor’s chief mechanic(s) shall be trained andcertified by the TBM manufacturer prior to the start up of the machine.

11.3.4 The Contractor shall provide, during the TBM assembly and the first 200m ofexcavation for each TBM, a team of three specialists for each working shift fromthe TBM / backup equipment Supplier(s). These three specialists shall beexperienced in TBM shield operation (1 person), electrical (includingProgrammable Logic Controller (PLC)) (1 person) and mechanical/hydraulic (1person) systems for the TBM / backup equipment. These specialists shall providetechnical assistance and training to all tunnelling and supervisory staff. The threespecialists shall be present onsite throughout the above work and additional

specialists shall be provided on a shift basis as necessary. The Contractor shallsubmit the CVs (endorsed by the machine Supplier) of all TBM specialists to theEngineer for acceptance 60 days before TBM start-up operations.

11.3.5 A technical representative from the machine manufacturer knowledgeable in the,operation and maintenance of the TBM shall remain on site with the Contractor’sstaff at the construction site for the whole duration of the tunnelling works. Thisperson shall attend any meeting related to the TBM, the associated equipmentand its performance.

11.3.6 During the tunnelling operation, the Contractor shall provide and maintain CCTV

(closed circuit television) systems with at least three (3) cameras placedstrategically within each tunnel drive at ring build, shaft bottom and muck pit areaor at other locations indicated by the Engineer. Each CCTV system shall belinked to colour monitors sited in the Engineer’s office and the cameras shallmove forward with the TBM.

11.3.7 STP operators and the Contractor’s chief mechanic(s) shall be trained andcertified by the STP manufacturer prior to the start of tunnelling. A technicalrepresentative from the STP manufacturer competent in the assembly, operation,maintenance and repair of the STP shall form part of Contractor’s staff at theconstruction site for the whole duration of the tunnelling works.


28/32



11.3.8 For a period of three (3) months prior to tunnelling, through to completion oftunnelling, the Contractor is to retain the services of a “mud” engineer orconsultant for the purposes of designing and where necessary modifying the Key

Performance Indicators (KPI) for the active slurry in all ground conditions. Thisperson is to have a minimum of 5 years relevant experience and be acceptable tothe Engineer. The “mud” engineer is to be available to attend meetings with theEngineer’s staff on site as required.

11.3.9 Three (3) months prior to the commencement of tunnelling the Contractor is toprovide the KPI for the active slurry in all foreseeable ground types and indicatewhere on the alignment these KPI’s are to be applied. These KPI’s are to addressas a minimum, Density, Marsh Funnel Viscosity, Plastic Viscosity, Fluid Loss, PHetc.

11.3.10 From these KPI’s specific hold points are to be derived for the commencement ofexcavation, suspension of excavation and commencement of manned

intervention. The “mud” engineer along with the Contractor’s QP(D) responsibleis to endorse these KPI’s and hold points.

11.3.11 The performance of the KPI’s themselves are to be monitored throughout theproject through the daily and regular site tunnel meetings If it is deemednecessary the KPI’s may be revised by the Contractor to the acceptance of theEngineer.

11.4 Primary Grouting

11.4.1 The primary grouting system shall be able to provide continuous, complete

backfill grouting of the annulus between the concrete segments and excavatedsurface when the TBM is operated in closed mode. The TBM shall continuouslygrout the tail void, as the TBM advances, through the tail shield using pipes orchannels embedded within the tail shield. A redundant pipe shall be provided ateach location for use in the event that the first pipe becomes blocked. Thegrouting system shall include a means for washing out grout residue betweeneach advance.

11.4.2 A method statement for the proposed grouting method and sequence should bepresented to the Engineer for approval before the commencement of tunnelling.

11.4.3 The Contractor shall ensure that grouting pressures do not result in ground heaveor overstress or distortion of lining or distortion or damage to gaskets or damageto other structures.

11.4.4 The Contractor shall use a two-component grout system, which will be batchedon the surface and then pumped down to the TBM. A retarding admixture shall beadded to the grout at the batching plant and then an accelerating admixtureadded and mixed at the point of injection through the tailskin grout ports.


29/32



11.4.5 The amount of grout used and the grouting pressure shall be recorded, and if thequantity falls short of that required to fill the space, further investigation andgrouting shall be carried out.

11.5 Secondary Grouting

11.5.1 Secondary grouting is the regrouting of lining and shall be completed as soon aspracticable but within 14 days of the primary grouting or when the face hasadvanced 50 m from the location of primary grouting whichever first occurs.Secondary grouting shall be at a pressure consistent with filling all voids but shallnot exceed the design pressures.

11.5.2 Secondary grouting shall be undertaken in selected rings by means of carefullyremoving grout plugs from the tunnel lining and drilling a hole, through a blow outpreventer, to the back of the existing grout and injecting grout to the design

pressure.

11.5.3 Upon completion of secondary grouting, threaded grout plugs shall be fullytightened into the lining. The grout plug fitted with a hydrophilic “O” ring shall becapable of withstanding full hydrostatic pressure.

11.5.4 Complete records shall be kept of all pressures and volumes of grout injectedduring the secondary grouting and submitted to the Engineer on a weekly basis.

11.6 TBM Dismantling

11.6.1 On completion of the drive, the machine shall be dismantled and removed fromthe tunnel.

11.6.2 The machine design shall permit dismantling of the structure of the machinewithin the shield skin, which may be left in place at the completion of the tunneldrive, and then transported back along the tunnel to the launch shaft for removal.Component dimensions should therefore be of a size compatible with suchprocess.

11.6.3 The Contractor shall submit a method statement explaining his proposals for thedismantling and removing the TBM and back up gantries.

11.6.4 If the shield skin is abandoned on completion of the tunnel drive a segmental orcast in-situ lining which complies fully with the requirements of the Specificationshall be constructed within the shield skin after removal of all mechanical parts.


30/32



12. DOCUMENTATION

12.1 At Proposal Stage

12.1.1 The Contractor shall submit with his tender (in a proposal document), details ofthe intended machine type, including specification and schematic drawings andname not more than three preferred machine suppliers. These details shouldinclude a description on his selection criteria with regard to soil and rock typesalong the tunnel drives and their characteristics, control of ground movement /settlement, groundwater pressures, calculations to demonstrate how TBM and itsassociated plants will achieve the required advance rates for different types ofgeology encountered, how interventions will be achieved and any otherconsiderations.

12.1.2 The Contractor shall submit details to demonstrate that his chosen TBM supplierhas the required experience, track record and capacity to design and fabricate

the TBMs to the Contractor’s programme.

12.1.3 The Contractor shall also supply with his tender a list of non-conformities,identifying any aspect of his proposed TBM which fails to comply with therequirements of this Specification, and provide a justification for such non-compliance.

12.1.4 In his submission, the Contractor shall provide evidence of two projects wherethe Contractor’s proposed type of TBM has been used in similar groundconditions as those likely to be encountered in the Works, detailed advance ratesachieved and ground settlements or settlement related incidents records.

12.2 After Award of Contract

12.2.1 As soon as possible after award of contract, the contractor shall confirm the TBMmanufacturer and shall make a joint presentation to the Engineer providingdetails of the TBM design, layout and specification prior to fabrication.

12.2.2 The Contractor shall, within 2 months of the Commencement Date, provide theEngineer with the following documentation:

i. Programme of manufacture, to include TBM design, procurement,manufacture, inspection, factory testing, transport, site erection andcommissioning and initial trial excavation periods;

ii. Drawings and technical data (draft) of the TBM and all major equipmentgroups;

iii. Spare parts listings, to include strategic items, estimated delivery times andstorage requirements;

iv. Emergency plans for gas incidents, fire incidents and water inundation;


31/32



v. Proposals demonstrating how the bearing will be changed from within thetunnel;

vi. Proposed manning levels;

vii. TBM launch and dismantling proposals.

The Contractor shall provide details of the TBM design for the Engineer’s reviewand acceptance. The manufacture of the TBM shall not commence until theEngineer has approved the design. The approval of the Engineer does not relievethe Contractor of any of his duties under the Contract.

12.2.3 Within three (3) months after the Contract award the Contractor shall providemanufacturers specifications for each type and size of separation plant and adraft STP operation manual which shall be specific to the plant proposed at site,and design calculations for the slurry circulation system.

12.2.4 During the design stage of the TBM supply, the Contractor shall provide draftmethod statements of how interventions will be achieved for the purposes ofcutter changing and cutterhead maintenance. Such Method Statements shouldbe finalised before commencement of tunnelling.

12.2.5 Three (3) months prior to commencement of tunnelling the Contractor is to submitto the Engineer for acceptance his method statement for the maintenance andrefurbishment of all cutter tools. The method statement is to detail as a minimumworkshop requirements, cutter disc refurbishment procedure, cutter disc hubwear limitations, limiting number of refurbishments for cutter disc hubs, cuttertypes for varying ground, cutter tolerance for replacement / reuse. The methodstatement is to be endorsed by the TBM supplier / cutter supplier.

12.2.6 The Contractor shall provide a scheme for

151567785 01 tunnel boring machine tbm specifications

Documents