Water transfer pipeline utilises multiple tunneling technologies including EPB

Sep 20, 2011

Construction site, general

As part of a £125 million project being undertaken by United Utilities known as the West East Link Main (WELM) pipeline, Tunnel Engineering Services (UK) Ltd recently provided a number of tunnelling machines for the completion of various tunnelling sections of the work, working in varying ground conditions and final pipeline diameters. Standard tunnelling and trenchless installations were used for the completion of the tunnelled works.

TES WELM 1.jpg
The TES 1800 EPM TBM on the WELM project showing the mixed ground carbide insert cutterhead configuration. (Source: Tunnel Engineering Services (UK) Ltd)
The WELM pipeline will carry water right across the North West of England from the Prescott Reservoir in Merseyside to the Woodgate Reservoir in Bury. The main contractor appointed to complete the works is J. Murphy & Sons. Overall the project will see the installation of some 54.5 km of 1,200 mm diameter welded steel pipeline which is designed to transfer up to 100 million litres of potable water, in either direction between the reservoirs every day, to safeguard water supplies to the catchments at either end of the supply line.
 
Technology choice
The selection of tunnelling and trenchless techniques for completion of the works was necessary because at various points along the proposed route the pipeline passed under various roads, motorways, rivers and railways. Further to these commonly encountered obstacles the route also crossed beneath areas of contaminated ground as well as areas of significant environmental concern.
After careful investigation of the various ground conditions on the different tunnelling sections of the pipeline it was decided that several methods of excavation would be required to complete the individual installations. Some of the sections utilised tunnelling equipment provided by Tunnel Engineering Services (UK) Ltd (TES). The machines were designed to install either 1,500 mm internal diameter and 1,800 mm internal diameter concrete pipes.
 
Ground conditions varied significantly across the various tunnelling sites. This meant that, with the different diameter requirements, five different TES manufactured or supplied machines were deployed. TES not only manufactures on site at its Oldham plant but also distributes USA-based Akkerman Inc tunnelling systems as the sole UK appointed representative. The machines used on the WELM project included:
  • One TES 1800 mechanised excavator machine which is owned and operated by J. Murphy & Sons.
  • One TES 1500 mechanised excavator machine which is owned and operated by J. Murphy & Sons.
  • One TES-supplied Akkerman 1800 TBM which is owned and operated by B&W Tunnelling.
  • One TES-supplied Akkerman 1500 TBM which is owned and operated by B&W Tunnelling.
  • One TES 1800 EPB TBM which is owned and operated by B&W Tunnelling.
 
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The EPB TBM being lowered into the start shaft of the first drive. (Source: Tunnel Engineering Services (UK) Ltd)
EPB TBM
The TES 1800 EPB TBM supplied to the WELM project and operated by B&W Tunnelling is a further development of the company’s established range of versatile and modular design of tunnelling equipment. TES’s system is designed specifically to deal with a variety of ground conditions in standard mode/configuration or in EBP mode in ground conditions from soft ground to competent rock. TES can manufacture this type of machine in diameters from 1200 mm i.d to the power, torque and cutterhead configuration required by the client for specific projects.
 
The specification for the TES 1800 EPB TBM with facility for EPB mode (with screw) or open mode (with a belt conveyor) for the WELM project included the ability to set the machine up for an 1,800 mm internal diameter pipejack with an adaptation which would allow the erection of segment linings if required. The machine was fitted with a carbide insert mixed ground cutterhead and supplied with a spare rock head, push cans, gripper/anti-roll cans as well as the segment erection adaptation. The power of the machine was 195 kW with facility to operate the cutterhead at between 0 to 9.5 rpm. The machine was designed and manufactured by Tunnel Engineering in just 16 weeks from placement of the order to delivery to site.
 
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Spoil removal during the tunnelling works on the first drive. (Source: Tunnel Engineering Services (UK) Ltd)
WELM Tunnels
Using the TES 1800 EPB TBM, the first drive on the WELM project required an installation of some 470 m. The ground conditions on this drive comprised mainly mudstone and weak sandstone. The TBM was fitted with a carbide insert cutterhead which was designed to handle these expected conditions. During the course of the drive the machine unexpectedly encountered a more competent rock strata. However, the design of the TBM, with its high cutterhead torque and cutter power enabled the machine to successfully handle the harder ground conditions without the need to modify the cutterhead in the ground. Even in the harder ground the TBM managed to achieve up to 25 m of advance in a 24 hour shift period.
 
The second pipejacked tunnel, undertaken using the TES 1800 EPB TBM, was driven entirely through a solid rock mass. Knowing this the TBM’s cutterhead was reconfigured prior to the start of the drive with disc cutters being interchanged for the carbide insert configuration used on the first drive. In this instance the drive length was 660 m, with a production rate averaging some 20 m in a 24 hour shift period. All drives undertaken on the project to date have been successfully completed.
 
TES WELM 4.JPG
The TES 1800 EPB TBM with the rock cutterhead configuration used for the second drive on the WELM project. (Source: Tunnel Engineering Services (UK) Ltd)
Commenting on the WELM project for TES managing director Geoff Clarke said: “Our aim has always been to provide tunnelling equipment that meets our client’s needs to the full. Our design of the TES 1800 EPB TBM has shown its flexibility and durability throughout the course of the WELM works. The ability to interchange the cutterhead configuration for the varying ground conditions proved very useful for the second drive. However, most pleasing from our point of view was the machine’s inherent ability to handle the unexpected harder ground encountered during the course of the first drive, proving the underlying strength and power built into the basic design.”
 
Steve Williams, managing director of B&W Tunnelling Ltd said: “I am delighted with the performance and reliability of the TBM. Tunnel Engineering has given an exceptional delivery on the machine and has the flexibility to ensure that the equipment was delivered on-site to our special requirements.”
 
 
>> This article is presented with permission of Trenchless Works / NoDig Media Services. <<

Contact

Tunnel Engineering Services (UK) Ltd

Heywood Street Waterhead Oldham OL4 2HA UK

United Kingdom

Phone:

00 44 (0)161 626 6005

Fax:

00 44 (0)161 627 0993

E-Mail:

info@tesuk.co.uk

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