Method Statement for Pipe Jacking Using an Automatic Tunneling Machine

Method Statement for Pipe Jacking Using an Automatic Tunneling Machine

The purpose of this method statement is to outline the sequence of casing pipe installation using Pipe Jacking and Herrenknecht Automatic Tunneling Machines with Slurry Material Removal (AVN machines).

Soil Investigation

A soil sample must be collected and submitted to an authorized laboratory for testing in order to determine whether pipe jacking is viable. Trial pits are very important for determining the uniformity, extent, groundwater table, and soil composition.

The Engineer’s interpretation of the Soil Investigation report, as well as any assumptions made, must be provided.

Existing Utilities Identification and Location

Before beginning any work, utilities must be located. All current utilities must be made visible.

The coordinates and levels of the utilities must be recorded, and a shop drawing of the current utilities and proposed pipe jacking pipeline must be created. It will subsequently be submitted to the appropriate authorities in order to get the necessary NOC(s).

Responsibilities

Project Manager

Project supervisor

Engineer in QA/QC

Site Engineer

Officer in charge of safety

Materials

The material must be purchased in accordance with the project specifications.

Smooth-walled casing pipe having a minimum yield strength of 36,000 psi (ASTM A1011).

Carrier pipes should meet local regulations.

Grout

Dielectric material

Plant and Equipment

• Setup of pipe jacking
• Jackhammer and air compressor
• Dewatering Pump with hydraulic pump and jack
• Thrust ring, spacer block, jacking shield, and guide rail are all included.
• Excavator Generator
• a wheeled bogey connected to an air wich
• Tipping truck

Workforce Requirements

• Personnel with excavation experience
• Pipefitter
• Operator
• Mason
• Carpenter
• General Laborer

PPE Checklist

Gloves and overalls with the company logo
Safety vest with reflective stripes
Helmets and protective shoes
Goggles for safety

Requirements of the HSE

All Personal Protective Equipment used by the workforce will be chosen and managed based on the results of the risk assessment.

All personnel involved in the work shall be provided with adequate information, instruction, and training on the wearing and usage of Personal Protective Equipment.

Only experienced individuals are allowed to work in the jacking pit and excavation area.
During operation, clean working conditions inside the jacking operation area must be maintained, as well as the removal of spoil, debris, and other materials.

Good ventilation must be provided for individuals working inside the casing pipe and performing excavation.

Around the works, good housekeeping must be maintained.

Adequate barricades, warning lights, or signage to protect traffic in the operation’s near vicinity.

In heavy winds, where control of the element may be lost, no attempt shall be made.

In the case of accidents on site or near-misses, the occurrence will be immediately reported to the Safety Officer, and all appropriate arrangements will be made.

Following the completion of the work, no soil or material shall be allowed.

Method Statement for Pipe Jacking

Preparatory Work

Before, during, and after pipe jacking operations, road surface levels along the pipe jacking route shall be taken 10mm on each side every 2m in collaboration with the Surveyor.

The launch and reception pits must be constructed. Pit sizes are determined by pipe diameter, jacking pipe length, and site conditions, and must comply with manufacturer recommendations. Please see the Technical Data Sheet for more information.

To provide a reaction against which to jack, a thrust wall must be constructed.

In poor ground, pilling or other special arrangements must be made to increase the reaction.

A concrete wall must be cast at the tunnel’s mouth to prevent soil collapse and smooth pipe jacking.

Jacking of Pipes

Hydraulic jacks driven by a diesel-powered hydraulic power pack shall be mounted on a support frame against the thrust wall and parallel to the line and gradient.

Banksman shall operate the hydraulic jack on instruction from the pit bottom.

A thrust ring must be installed between the steel pipe and the jacks to disperse the jacking force onto the pipe and keep it from buckling.

The leading edge of the first pipe shall be contoured to suit the soil condition, i.e. a hood shall be utilized on soft ground.

Using an air compressor and a jackhammer, excavate the soil at the face.

If water is encountered during excavation, a dewatering system of sufficient capacity must be maintained to remove water continuously, keeping the excavation free of water, and while the backfilling operation is underway.

The excavated soil is loaded into a muck skip on a wheeled bogie, which is manually pushed into the pipe and dragged out to the pit by an air winch located between the jacks.

As the excavation in the reception pit continues, the pipe will be jacked forward.

When the pipe has been pushed to the end of the jack’s stroke, the jack will be retracted and a spacer block will be placed between the jack and thrust ring. The jacking will then resume.

This procedure must be repeated until the pipe is completely pushed in.

The next pipe should be welded into place at the pit bottom, and the operation should be continued until the drive reaches the reception end.

During the pipe jacking process, the surveyor must check the line and levels on a regular basis.

Daily activity logs must be maintained on-site for all of the above activities, and they must include:

• Casing pipe advancement’s start and end times.
• The total length of casing pipe that has been installed.
• The maximum jacking force applied during casing pipe section installation, including forces required to restart jacking after system shutdown. Each dissembled ground condition mined has a general description.
• Readings from the settlement monitoring system.

Installing Carrier Pipe

Following the installation of the casing pipe, the carrier pipe must be laid to line and level.

Spiders clamped to the pipe or flat bars welded over the steel sleeve must support the carrier pipe.

Once all of the carrier pipes are securely fastened and checked, a breather pipe will be installed at the soffit.

Then, at the end of the steel pipe, concrete/block work head walls must be constructed.

Grouting

Prior to grouting, the carrier pipe should be filled with water and, in the case of uPVC, circulated to avoid hydration heat damage.

The annulus between the carrier pipe and the sleeve must be filled with 1000kg/m3 foam concrete.

Continuous foam concreting is required until the sleeve is entirely filled.

Design of Grout Mix:

SRC: 432 kg

1214 kilogram sand dunes

Water (360 kilograms)

3 liters of superplasticizer

Slump: Collapse

Backfilling

Backfilling will begin after all relevant authorities have completed and approved inspections.

According to specifications, the thrust and receiving pit must be backfilled layer by layer.

Following the completion of backfilling, the original condition of the ground must be restored.

Herrenknecht Automatic Tunneling Machine with Slurry Material Removal Technical Data Sheet (AVN machines).

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