Work has now kicked-off on a major project for MJ Church, the Dorset Visual Impact Provision Project, (VIP) working for Morgan Sindall Infrastructure on behalf of their client National Grid.
The project will run for two years, so we thought you’d like to meet the team working on the project, know what we are delivering and what the VIP project is.
About the project
As you know National Grid own and manage the electrical transmission network in England and Wales, they are also responsible for balancing the system (meeting demand), and the generation from power stations and renewables. The ‘transmission’ network carries electricity around the country at high-voltage to ‘distribution’ networks, owned by various providers, to homes and businesses. The transmission network operates through overhead powerlines, pylons and underground cables.
Above the village ofMartinstown stands the Hardy Monument which draws many visitors for its far-reaching views across the DorsetArea of Outstanding Natural Beauty (AONB) to Portland and the sea. National Grid, as part of a national programme, have undertaken to reduce the visual impact of its Pylons and overhead lineson this viewby replacing them with buried underground cables. The Dorset VIP will see a total 90kmof cables over 4 trenches being buried in the undulating and in some cases very steep countryside.
The MJ Church site team is headed up by Senior Project Manager Dan Baker, who has been working on the innovative approach MJ Church has adopted for delivery of the trench construction. The project is both logistically and technically challenging. Virtually the whole 9km route is only accessible from one access point off the A35 in the north, so we are constructing a cross country Haul Road not only to enable our own works, but also capable of carrying the 70t Drums of Transmission Cable.
The initial challenge for MJ Church is to expose the rich archaeological history that lies just beneath the topsoil. In the first month, several Paleolithic and Neolithic dwellings, cremation pits and countless flint tools have been uncovered.
In November we will begin the trenching operation. There are four trenches 1.4 m deep, 2.2m wide each containing three 250mm cable ducts and some smaller communication ducts. The ducts are laid on and surrounded in compacted cement bound sand. From the outset our approach to the project has been based around three principles:
- Safety – keep personnel out of the trench.
- Production Line duct train – how can we reproduce a quality product day after day
- Innovation – what can we do better
To this end we are making full use of GPS technology for the excavations which reduces the people/plant interface issues and gives us an accurate measure of volumes moved. We have built two bespoke duct laying trailers that allow assembly to be carried out on a clean safe platform above the trench.
At the southern end of the route the Dorset Ridgeway drops 60m in level over a 1:1 gradient, far too steep for any conventional plant to operate safely. To overcome this we will be deploying a MenziMuck spider excavator which was originally designed to work in the Swiss Alps.
Through research and some trials at Star Farm HO and considerable investment in new plant and technology, some of which is being introduced to the UK for the first time, we aim to be the best solution provider.