Better earthworks operations

New technology improves efficiency and accuracy of earthworks operations

Bulldozer fitted with GPS tracking
Bulldozer fitted with GPS tracking

Challenge summary:

To manage up to three diverse earthworks projects in Telford, Wrexham and Manchester, simultaneously from one office in Wolverhampton - miles apart geographically and with tight programmes.

Challenge solution:

Taking the role of engineer and project manager, Dean Wigley can measure progress accurately on all three sites remotely through the use of specialist construction equipment supplier Topcon's "Sitelink" site management system based on GPS instrumentation connected to a central computer network.

Sitelink is a system which allows the dozers and excavators to be part of a computer network where data can be shared and messages sent and received, so that an engineer's drawing can be updated remotely, instead of work stopping until he or she arrived on site with the new drawing information.

Telford rock

The Telford project involves removing 12,000m3 of rock material from the site to pre-determined minimum depths to allow roads, foundations and an underground sewer network to be installed for a new housing development. Sitelink is being used on the project to relay excavation progress to head office. Topcon's 3D GPS instrumentation on two of McAuliffe's machines measure the line and level of the excavation while a Topcon base station on site ensures GPS readings are accurate to approximately 20mm.

Engineers' design drawings have been uploaded onto computers into two of McAuliffe's machines while Topcon 3D positioning instrumentation continuously tracks the actual position of the blade or bucket and compares this to the design data in the drawing. Any discrepancies are automatically corrected via the machines' hydraulics to ensure the machine is working accurately and efficiently.

"By using 3D GPS and Sitelink I have all the information I need to know how far we are from formation level," says Dean. "Real time progress can be monitored and conveyed to the client at any time."

A single engineer can check the accuracy of earthworks activities to excavate or re-profile the ground without constantly returning to site to check progress against drawings. There is a messaging facility on the units which also allows communication between excavator or dozer operative and engineer.

"So if there has to be any degree of over-dig due to, say, large rocks or other obstructions which have to be removed, I can advise the operative of what to do rather than for work to come to a halt," explains Dean. "On occasion, if we encounter a large obstruction, we can survey it instantly and relay this information to our client." The client can then work up a strategy or design to overcome the obstruction, armed with the exact coordinates of its location.

"Having the actual data relayed in front of you also gives you the knowledge from which to make decisions and can improve the accuracy of excavations by ensuring there is no over- or under digging." Ultimately, this has a positive effect on project cost and efficiency. Print-outs provide quality assurance of the work carried out and also ensure a smoother handover at the end of a job. At Telford excavated rock will be crushed on site and replaced to form a sub base –monitored, measured and checked using Sitelink and 3d Positioning. "From an engineering point of view, using this site management system has shaved a couple of weeks off the programme," comments Dean.

Wrexham spoil mound

The project in Wrexham involves relocating a spoil mound containing contaminated material under a Materials Management Plan, to form a bund on a new PFI waste disposal site. To overcome the challenge of building up the ramps of a three-dimensional bund, its profile has been modelled using CAD and the information uploaded onto the dozer's on-board computer. The dozer, therefore, works to the co-ordinates of the drawing and this ensures compliance with Waste Management Regulations.

McAuliffe currently has two 3D machine control units which can be fitted into four of its machines wired up to receive the units. Using Sitelink also has safety benefits, says Dean. "At Wrexham we are able to survey and monitor progress without risking exposure to contaminants in the ground and entering controlled working zones. So the operatives could focus on their job and the complex earth-shifting operation."

Manchester demolition

At Manchester, McAuliffe has a contract to demolish existing buildings, excavate to formation level, crush demolition rubble and spread it over the site to form a piling platform. The entire operation is making maximum use of Sitelink and 3D Positioning. Dean explains that Topcon technology is improving safety and quality on this 30-plot housing development site and many more to come.

Automation equals efficiency

"We now have fewer operatives on site, so there are fewer safety risks of working near moving plant and we don't need setting-out points – which often get destroyed in the process anyway. By using a more automated system, our work is more accurate and we save fuel and energy by only digging and shifting the correct amount of earth to get the job done. For me, working remotely means that I can control a number of jobs and respond to all their needs much more efficiently than if I had to get into a car and drive to each site."

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