Anabeeb Pipeline Division

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1.0 Purpose

Micro-tunneling is a technique for installing non-man entry size pipeline using a steerable remote control pipejacking technique, introduced to facilitate construction of underground utilities, e.g. pipeline, electric cables, telecommunication ducts, sewers etc., in circumstances where disruption to the services and local environments should be minimized.

2.0 Definition

Pipe pushed through the ground using high performance hydraulic equipment with minimum disturbance to the sub-strata for the pipes dia from 20" and above using steerable head remote controlled, which guarantees a high level of accuracy.

3.0 Responsibilities

3.1 The Division Manager is responsible for ensuring the integrity of the process in accordance with contract requirements.

3.2 The Field Supervisor is responsible for Safety and process operations to an acceptable level.

3.3 The Q.C. Coordinator shall verify the production activities on a spot check basis (depending upon the contract).

3.4 The Safety Officer is responsible for verifying that Safety requirements are being met, on a spot check basis (depending upon the contract).

4.0 Description Of Microtunnelling Method Statement

4.1 Thrust & Reception Pits

For this project the thrust and reception pit will be constructed on either side of the two designated obstacles - a road in one case and existing utilities in the other.

The thrust pit dimensions: 19.5 m long x 9 m wide x depth to suit (approx. 0.25 m below pipe invert) for 12 m long pipes.

Sheet piling and / or dewatering and excavation works will be executedwhere required depending on soil conditions, depth of the pits and requirement of the Client.

On completion of the thrust pit excavation, a concrete blinding layer is cast to correct level or gradient for the sole purpose of setting up equipment in a clean and safe environment.

Survey points are then transferred from the datum points and fixed points set in the compacted base slab for easy reference.

Anabeeb Pipeline Division

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The Micro-tunneling rig will be set up in the launch pit on the level concrete pad. A double skinned, steel wall will be installed against the rear wall of the pit to withstand the pipe’s thrusting force.

The reception pit is a receiving pit created to recover the steering head and equipment. This is excavated at termination point. The reception pit dimensions: 5 m long x 9 m wide x depth to suit.

The integrity of the pits during Microtunnelling will be verified and control measures will also be taken.

4.2 Technical Method Statement - Microtunnelling

4.2.1. General

The Herrenknecht Microtunnelling system AVN coming from Germany but used all over the world includes all equipmentsnecessary to drive non-man entry tunnels by the pipejacking method.

The system is designed for tunneling, without the use of ground improvement process such as compressed air, ground treatment or freezing in water bearing grounds with a head of up to 15 meters of ground water.

4.2.2 For this project Microtunnelling consists of a remote controlled approx. 87 inch tunneling shield to excavate a bore into which the 84” OD, 12 m section steel pipe is installed.

The minimum cover recommended is 4 m and the minimum horizontal clearance from other utilities at crossings shall be minimum 1.5 m. The minimum distance recommended from the edge of the obstacle (road in the case of this project) to the edge of the pits (thrust & reception) is 10 m.

The pipe is connected to the back of the micro-tunneling shieldwith a pipe carrier frame to maintain the pipe at intended alignment followed by a push block to develop a uniform distribution of jacking pressure around the end of the pipe.

As the shield excavates the borehole, it is pushed forward by a set of hydraulic jacks positioned within a frame in the thrust pit. Further pipes are positioned onto the frame, connected to the pipe string and then jacked forward. This process continues until the tunneling machine arrives at the reception shaft where it is disconnected/cut from the pipe string and retrieved, leaving behind a length of installed pipe which is 30 to 135 meters(approx.) each for this project.

Anabeeb Pipeline Division

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The only excavation required from the surface is for thrust and reception pits.

Excavation is carried out by the tunneling shield and there are a range of cutting heads which can be used, depend on the soil type and ground water levels. The heads may be fitted with blades for soft soil, picks for hard soil/soft rock and disc cutters for hard rock. Once excavated, the soil can be removed either by vacuum or mechanical auger, as slurry or by compaction around the product pipeline bore. In the first of these systems, vacuum pressure is used to suck the material away from the tunneling face, back to tanks on the surface. Alternatively, a flight of augers running, through the newly installed pipeline can be used, in this system the soil is collected in a skip and lifted out of the drive shaft. The auger system is preferred for short drives since the removal rate is considerable faster than other systems.

4.2.3 Cutting Head

The mixed/rock cutting head is used for this project. The cutting wheel is equipped with carbide tipped tools to cut the entire face of the tunnel. Excavated material passes through openings in the cutting wheel into the crushing/mixing chamber.

Here, the conical crusher reduces the materials to a size suitable for conveying to the surface super sucker by pump. Water is injected through nozzles in crushing/mixing chamber to assist mixing without blockage.

The cutting wheel is driven by hydraulic motors located within the cutting head assembly, thus excavating and crushing power is not dependent upon distance from the launch shaft as with auger driven equipment.

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The cutting head assembly consists of two sections, which are articulated to allow movement of up to approx. 3.5 degrees in any direction to enable precise steering of the thrust. To customize the cutting head to the carrier pipe a back up pipe piece 2.5 m long must be used.

In the slurry removal system, water or bentonite may be used to convert the soil into slurry at the cutting face. The slurry which is water based is then pumped to the surface along the pipe within the product pipeline. The soil is then collected in a processing plant where it is removed and the slurry recycled back to the cutting face. The slurry system can be used to control external groundwater by balancing the slurry pressure so that it offsets the ground water pressure. The slurry system is usually more suitable for long drive lengths, especially in granular soil and where there is ground water.

The control container is equipped with a slurry flow meter which helps the operator to calculate the volume of excavated material. Excess suction of excavated materials results in ground/road settlement. This can be avoided by closely monitoring the slurry flow meter and controlling the suction.

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The ground conditions will have large effect on the choice of Microtunnelling system for a particular situation, as they will determine the type of machine to be used, the cutting head, the soil removal system and the jacking forces required.

Microtunnelling machines can be steered to ensure the correct line and level of the product pipeline. The accuracy of the bore is normally determined using laser guidance control systems. The machines are operated from a control cabin at the surface.

4.2.4 Length of Thrust

Depending upon machine size, thrusts of up to 100m between launch and reception shafts are easily achieved. Thrusts of 160 m have already been successfully completed by Anabeeb.

Limitations are reached by jacking pipe strength and laser resolution, thus reducing accuracy over longer distance.

The standard machine package includes 100m, of the hydraulic hoses, electric cable and slurry pipes.

4.2.5 Control/Power pack Module

The control/power pack module is housed within an ISO standard freight container providing rapid relocation from shaft to shaft.

The container may also be used with AVT type machines using auger material transport, if so required at a later date.

4.2.6 Guidance System

The HERRENKNECHT ELS guidance system has been developed specifically for use with these Microtunnelling systems. This consists of a target box and a laser unit.

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A target location is hermetically sealed within the cutting head for the impinging laser beam to define the exact position of the machine. An encoder is located in the launch shaft to provide continuous measurement of the length of thrust.

Via the main processor, the actual position of the cutting head is calculated and displayed graphically on a color monitor built into the control panel. A complete record of the thrust is stored in the processor and a printout is available at any time during the thrust via the printer provided in the control/power pack module

Calibration of the tunnel machine and other associated equipments will be conducted after the set-up of the spread and just before start of tunneling. Contractor and Client if required can witness and certify the process.

Failure/breakdowns of all tunneling equipments will be rectified by Anabeeb Mechanics/technicians who will be present at site/base station during tunneling operations.

4.3 MANPOWER (Not limited to)

Manpower & Equipment mobilization will depend on the site conditions; the lists below are provided as typical and may need later adjustment.

Management & Manpower No.

1. Division Manager Pipeline : 1 Part Time2. Microtunnelling Operations Manager : 1 Part Time3. Supervisor/ Microtunnelling Operator : 14. Miners / Labours : 45. Mechanic : 16. Welder : 17. Electrician : 1 8. Heavy Duty Driver : As Required

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4.4 Plant & Equipment (Not limited to):

1. Jacking Rig 1200 x 1300 x 1300 : 1 2. Mixed cutting head : 13. Back-up pipe : 14. Control container : 15. Bentonite pump/mixer : 16. Process water feed system : 17. Sediment separator : 18. Flatbed Truck : As required9. Low bed Truck : As required10. Mercedes lorry/boom truck : As required11. Water tank 13m3/separation tank : 112. Workshop Container : 113. Office Container : 114. Generator : 115. Thrust pit construction materials : As required16. Bentonite : As required17. Compressor 450 cfm : 118. Jack Hammer : 219. Safety Barriers & Signs : As required

4.5 Insertion of spacers and grout

For project where insertion of spacers and grouting of the annulus is required, the below mentioned procedure is followed.

On every Carrier Pipe one or more spacers with maximum distance of 3 mtrs will be installed, these spacers allow the pipes to be in a straight line. The spacers are mounted on the Carrier Pipe to push inside the Sleeve pipe, as required.

Once the spacers and carrier pipe have been inserted, both ends of the sleeve pipe are closed with steel plates and both the Carrier Pipe ends pass through the steel plate.

The Carrier pipe if required is filled with water to ensure the cooling during grouting and to guard the pipes integrity.

The holes will be made at both ends of the sleeve pipe of 4” to grout and at the other end to pass the air, the grout is pumped through in the sleeve pipe using the pump.

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This pumping process will continue until the sleeve pipe is full. The sleeve pipe will be full when the grout flows through the other end (hole) of the pipe.

A rough calculation will be performed prior to beginning the operation to determine the approximate volume of grout required to fill the sleeve pipe. This volume will then be compared to the actual amount to ensure that the sleeve pipe is full.

The water (if filled) is removed from the Carrier pipes.

5 SAFETY

5.1 GENERAL

ANABEEB personnel are supplied with Personal Protective Equipment (PPE):

General PPE supplied are, overalls, safety shoes or boots and helmet. Other protection such as safety glasses/goggles, gloves, ear plugs, safety belt/harness, masks are supplied appropriate for the task being performed.

5.2 WORKMANSHIP STANDARD

Selected work force shall be used for each process based on knowledge, skill and experience.

5.3 SIGN AND SAFETY BARRICADES

During thrust boring appropriate signs and safety barricades (soft/hard) will be positioned so required, to prevent inadvertent access.

Anabeeb Pipeline Division

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5.4 PERMITS

To prevent any job delays, all necessary permits and ID’s have to be available before commencing any mobilization/works:

Entrance permits for all personnel + vehicles on the working site. Cold & Hot permit. Confined space entry permit. Permit for 24 hours operation.

Field Supervisor shall carefully study the required permits available in order to control the situation as mentioned in the permit complying with the actual safety. Should there be doubts; advice must be obtained from the person or authority that has granted the permits.

6. QUALITY

6.1 GENERAL

All the works will be executed according to ANABEEB’s quality system ISO 9002 and the quality standards as set by the Client.

6.2 REPORTING

Daily progress reports, detailing plant, equipment and occurrences are to be signed daily by ANABEEB and contractor representatives, as per ANABEEB’s Procedures and or contractor's demands.

After finalizing each boring, a job completion certificate will be produced indicating the installed length according to the contract specifications, which will become the acceptance for invoicing.

Anabeeb Pipeline Division

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6.3 TYPICAL ORGANIZATION CHART

PLD(QA/QC)

PLDHSE

OFFICER

LABOURERS

MECHANIC WELDER OPERATOR DRIVER

PLDSUPERVISOR

PLDOPERATIONS

MANAGER

PLDPROJECT

CORDINATOR

PLDESTIMATOR

PLDPROCURMENTCORDINATOR

DIVISION MANAGER