Pipe Jacking
An introduction to pipe jacking prepared by the
Pipe Jacking Association
Steven Cowell - Introduction
J. Murphy & Sons Ltd.
Estimating Manager - Tunnelling
26 years in the tunnelling industry
Design, project delivery, planning & estimating roles
Pipe Jacking Experience
Hand excavation, road-header & back-hoe shields
Open, EPB & slurry TBM’s
Dewatering, ground treatment & compressed air
Diameters from 1.0 to 2.5m
Drive lengths to in excess of 500m
Agenda
Introduction to pipe jacking and micro-tunnelling
Excavation methods and machine technology
Drive lengths and diameters
Jacking loads
Jacking pipe materials
Guidance and controls
Site investigation and ground conditions
Comparison with open trench and segmental tunnels – H&S, environmental and
technical benefits
PJA research
Some Murphy pipe jacking examples
What Is Pipe-jacking?
The PJA definition
“Pipe jacking is a technique for installing underground pipelines, ducts
and culverts. Powerful hydraulic jacks are used to push specially designed
pipes through the ground behind a shield at the same time as excavation is
taking place with the shield.”
Pipe
diameters 0.45m to 2.4m commonly available in the UK
Larger
The
diameters regularly used overseas
term micro-tunnelling is used for the diameters 0.45m to
1m
Jacks in excess of 1km in length undertaken in the UK
Typical Construction Sequence
Sink launch shaft, using
whichever method is
appropriate to the ground
conditions.
Sink reception shaft, using
whichever method is
appropriate to the ground
conditions.
Install jacking rig
Set up system, control
container, separation plant
and pumps.
Launch TBM and
commence drive.
Complete drive and recover
TBM from reception shaft.
Common Applications
Sewerage and potable water construction
Gas and water utilities
Industrial pipelines (e.g. oil, chemical etc)
Electricity and telecoms utilities
Pedestrian subways
Excavation Methods & Machine Technology
Then - The good (bad!) old days:
Manual excavation & loading
Common up to early1990’s
Health & safety issues
HAVS
Manual
handling
Occupational health
Now - Very limited manual excavation
Max. drive length 100m at >1.2m i.d.
Max. 2 drives or 150m in one project
Must seek HSE guidance
Strict controls put in place
Excavation Methods & Machine Technology
Machines are available for pipe jacking in the majority of ground conditions
Backhoe Excavator
Road-header
Earth Pressure Balancing TBM
Open Face TBM
Slurry TBM
Machine Technology
Backhoe Excavator
For competent and stable ground conditions
E.g. clay, dry / stable sands
Suitable above water table / in dry ground
However, can be used in conjunction with
dewatering
Machine Technology
Open face cutter booms (road-header)
For strong cohesive soils and weak to
moderately strong rocks
Operated above water table
However, can be used in conjunction with
dewatering
Machine Technology
Tunnel Boring Machines (TBM) - Open face
For stable face conditions, including competent rock.
Various cutting heads available to suit a broad range
of ground conditions
Suitable above water table / in dry ground
Can be used in conjunction with dewatering
Spoil removed via a conveyor belt or auger
Machine Technology
Earth Pressure Balance (EPM) TBM
For less competent ground conditions
Can be used in saturated ground
Most suitable for cohesive soils
E.g. clays, silts, etc.
Excavation controlled by continuous
flight auger
Additives for face / spoil conditioning
Machine Technology
Slurry TBM
For less competent ground conditions
Can be used in saturated ground with high pressure
Most suitable in granular soils
E.g. sands, gravels, cobbles
Excavation controlled by slurry system
Microtunnelling Systems
Fully guided machines
Controlled from surface
1m i.d. and below
Non man entry
Similar to larger diameter
pipe jacking machines
Two options:
Pressurised slurry
Screw auger
Drive Lengths and Diameters - HSE Recommendations
Jacking Loads - Capacity
Ultimate jacking load dependent upon:
Pipe load capacity
Jacking wall / restraint capacity
Diameter, length & weight of pipes
Ground & groundwater conditions
Excavation method & control
Cycle times / working patterns
Alignment control
Maintaining annulus
Lubrication
Main jacking station capacity
Intermediate jacking stations (number /
capacity)
Jacking Loads - Reduction & Control
Good practice should include:
Correct choice of excavation method
Open,
EPB, slurry
Control of groundwater
Dewatering,
Good alignment control & correction
1º
= 50 to 90% reduction in pipe capacity
Maintenance of cut annulus
Cut
diameter, TBM / shield over-cut
Good lubrication
Injection
ground treatment
points, Bentonite, water & polymers
Correct choice of intermediate jacking stations
Number
required, capacity & position
Jacking Pipe Materials
Concrete jacking pipes
BS EN 1916
Clay pipes:
BS EN 296-7 & BS EN 12899: 2000
Steel pipes
GRP pipes
Guidance & Control
Continuous & real-time
Normally laser guidance
Maintains accuracy
Line, level & attitude
Permits remote operation
“Smart” targets
Camera targets
Giro compass (curves etc.)
Site Investigation
Ground Conditions
Comparison with Open Trench
Comparison with Open Trench
Pipe jacking
Comparison with Open Trench / Segmental Tunnelling
Technical
Comparison with Open Trench
Minimal surface disruption and
reinstatement
Fewer utility diversions
Comparison with Segmental Tunnelling
Inherent strength of pipeline
Smooth internal finish
No secondary lining
Less joints
Watertight
Control of settlement
Comparison with Open Trench / Segmental Tunnelling
Health & Safety
Comparison with Open Trench
Utility disruption minimised
Public interface reduced
Comparison with Segmental Tunnelling
Reduced labour requirement
Reduced installation time
Reduced manual handling
Non man entry where possible
Comparison with Open Trench
Environmental
Avoid damage to services
Reduced disruption
Maintains highway integrity
Carbon footprint
90% fewer vehicle movements
Less spoil
Less quarried material
Carbon Footprint & PJA Calculator
The PJA has worked with the North American Society of Trenchless
Technology (NASTTBC) which is at an advanced stage of developing a carbon
calculator for trenchless technology
The carbon cost of traffic disruption has been studied by the Centre for the
Advancement of Trenchless Technologies (CATT) and at the Department of
Civil Engineering at the University of Waterloo, Ontario
Subsequently NASTTBC developed a carbon calculator tool through the
University of British Columbia
A combination of the reduction of traffic and trenchless construction outputs
resulted in carbon reductions in excess of 90% compared to open trench
construction.
The PJA has developed a UK tailored product and incorporated TRL/Halcrow
traffic data developed for NRSWA impact studies carried out for UKWIR
The “Carbon Calculator” tool is available from the PJA website
90% Reduction in Carbon Emissions
“When compared to open trench
excavation pipe jacking can
reduce construction related CO2
emissions by 90%.”
PJA & University Research
Two decades of research
Oxford, Cambridge and Newcastle Universities
involved
Supported by water companies and the EPSRC
Research both laboratory and site based
Research Projects
Laboratory testing of model jacked pipes
Field testing of performance of pipes
Finite element analysis of concrete jacking pipes
Full scale testing of concrete pipes
Soil conditioning and lubrication materials
Field testing of soil conditioning and lubrication methods
Slurry management (spoil disposal medium)
Guide to Best Practice
Soils investigation
Excavation systems
Temporary and permanent works
Jacking lengths and friction forces
Best installation practice
Worked examples and checklists
Additional Applications
Box Sections
Subways
Roadways
Other uses
jacked arches
bridge slide
foundations
Pipe-jacking Examples
Preston 7 UIDs - Direct Pipe Installation
Client: United Utilities
Ground Condition: Silts, sands, clays, cobbles
Dimensions of Drive: 2 drives x 1.5m i.d. x 865m
Machine: Herrenknecht slurry TBM
A new technique - used only14 times worldwide
First use in the UK
The longest drive to date worldwide
1st drive currently 80% complete
Pipe-jacking Examples
Preston 7 UIDs - City Works
Client: United Utilities
Ground Condition: Sandstone
Pipe-jacking: 5 jacks x 1.5m i.d. 550m total
Machine: Open face rock TBM
Challenges:Restricted
Abrasive
urban location
rock conditions
Pipe-jacking Examples
Lower Lea Valley Cable Tunnels
Client: Olympic Delivery Authority
Ground Condition: Sands / gravels and
beneath a high water table
Pipe-jacking: 2.52m i.d. x 70m length
Machine: Iseki slurry machine
Challenges:- Highly permeable sands and
gravels with water close to ground level
Pipe-jacking Examples
Taplow
Ground Condition: Chalk with high
permeabilities
Pipe-jacking: 1.5m i.d. x 140m
Machine: Iseki slurry machine
In Summary . .
Engineering integrity
Low capital costs
Low maintenance
Cost-effective
Safe installation
Environmental benefits
Extensively used worldwide
0.45m to 3m diameters
Long drive lengths
Good engineering performance
Thank you for listening.
Any questions?
Pipe Jacking Association
10 Greycoat Place, London SW1P 1SB
Tel: 0845 070 5201 Fax: 0845 070 5202
Email: [email protected]
Website: www.pipejacking.org