Skip to main content

Motorway's tricky cable installation

The UK is now benefiting from the installation of sophisticated automated traffic management equipment and information signs on its motorway network. But with heavy traffic volumes on these roads, novel techniques have had to be implemented. One such operation, organised by client The Highways Agency and its consulting engineer A.One+, has recently been underway on the M56 motorway between Junctions 9 and 16 in north-west England under the Triple Package Advanced Works designation. To minimise traffic distu
February 6, 2012 Read time: 3 mins
The UK is now benefiting from the installation of sophisticated automated traffic management equipment and information signs on its motorway network.

But with heavy traffic volumes on these roads, novel techniques have had to be implemented. One such operation, organised by client The 2309 Highways Agency and its consulting engineer A.One+, has recently been underway on the M56 motorway between Junctions 9 and 16 in north-west England under the Triple Package Advanced Works designation.

To minimise traffic disturbance, it was decided to use horizontal directional drilling techniques for the majority of the crossing installations for the fibre optic cabling system. Ground investigations were carried out using bore holes at each crossing location and on both sides of the motorway, indicating that this was a suitable trenchless technique for the conditions.

The main contractor for the trenchless installation work was AE Yates, working with sister company AE Yates Trenchless Solutions. The majority of the crossings, 25 out of 26, were completed using various HDD drilling rigs and followed the project plan. The HDD bores varied in length between 40-100m and comprised the installation of four-way 110mm diameter conduits.

However, at one particular crossing location, the work site was restricted in space, both on the launch and reception sides, which meant that the use of the HDD technique was not possible, so another option had to be found.

Investigation of the options available led engineers at 2305 AE Yates to select the pilot auger microtunnelling technique for the limited-space site.

With the auger crossing site comprising compact sand and weathered sandstone, the correct choice of installation technique was vital, while still being able to operate in the confined spaces on either side of the motorway.

Careful consideration of the options available led to the choice of a 2302 Perforator PB85V pilot auger microtunnelling system. The auger crossing comprised the installation of a 45m long, 300mm diameter 'lost steel tube,' which was to act as a carrier pipe for four 110mm diameter conduit pipes supplied by Drain Centre of Wigan, into which the fibre optic cables for the traffic management system would be installed.

To complete the crossing the rig was located in the start shaft on the line and level required for the crossing. As the pilot bore progressed, the use of the laser-based optic electronic navigation system (OEN) allowed the pilot bore to be driven along the required route of the bore towards the target point.

Once the pilot bore was completed the cutting head was changed to an auger system to enlarge the pilot hole, removing spoil with the auger chain installed behind the auger cutting head. With the bore at the correct size the pipe installation was then completed by jacking the necessary pipe into place behind the auger chain while removing the displaced auger units at the reception shaft.

The HDD installations took an average of two restricted-hours night shifts each to complete, because of traffic management constraints, restricted working space and a requirement to dig the HDD rigs in at each site alongside live traffic on the M56 motorway.

Works on the auger crossing installation took five day shifts following shaft construction and site preparation. Using these guided boring systems allowed a tricky project to be completed on a site close to a motorway and in a limited space, a notable achievement.

For more information on companies in this article

Related Content

  • Tunnelling challenge on German project
    June 13, 2012
    A massive construction project has been underway deep in the heart of the Schnecktal valley area in Germany. From the surface, though, you would never be able to tell. The majority of the work is underground, as a joint-venture team led by German contractor Wayss and Freytag Ingenieurbau builds the nearly 7km long Finne Tunnel. After a few years of tunnel boring operations, the contractor is at work finishing the interior of the tunnel, slipforming first the tunnel’s floor and then a walkway with its GOMACO
  • Bridge drainage solution prevents water damage
    February 10, 2012
    Pipeline & Drainage Systems (PDS), is pointing to its EnviroDeck drainage product saying that unless properly drained, water can cause severe damage to bridges, particularly on deck surfaces where it may become trapped.
  • Scotland’s new Queensferry Crossing over the Forth Estuary
    December 23, 2015
    The new Queensferry Crossing under construction in Scotland will be the third landmark bridge spanning the Forth Estuary - Mike Woof writes When the new Queensferry Crossing over the Forth Estuary opens at the end of 2016, it will be the third landmark bridge to be built spanning this short stretch of water. Lying alongside the existing road bridge and the historic rail bridge, this new structure will be as groundbreaking as the two earlier crossings were at the time of their construction.
  • First stay cable installed on UK’s Mersey Gateway bridge
    October 31, 2016
    The first stay cable, 52m long, connecting the Mersey Gateway south pylon to the main bridge deck, has been installed on the Mersey Gateway Project.