HS2 speeds up with digital earthworks

A Blackwell Caterpillar 352F LME mass excavation excavator fitted with Trimble Earthworks

The Eiffage Kier JV is pioneering the latest digital technology for earthmoving on an 80km stretch of HS2. Peter Haddock visited the site.

On a site near Southam in Warwickshire, the latest digital technology is being used to plan and execute a vast muck shift, potentially a transformative approach to major infrastructure projects.

This is the 23ha ‘heave monitoring site’, part of the Eiffage Kier JV’s civil engineering contract for HS2, which extends along 80km of the route, between the Chiltern Tunnel in Buckinghamshire and Long Itchington Wood close to Southam.

Contractor Blackwell is currently on site, with a fleet of 17 earthworks machines performing different roles, each equipped with GPS technical receivers and other digital technology, while overhead, a drone is used to survey the site (see below).

The site aims to gain a better understanding of ground movements and map the behaviour of heave in clays when excavation occurs. Eiffage Kier has drilled 34 boreholes across the site, each housing specialist sensors that will constantly monitor and measure sub-millimetre movements in the ground. This information is mapped against the daily excavation, using GPS location data, to provide the Eiffage Kier engineers with critical insight as to how the ground is behaving as it is unloaded.

Engineers use this data to validate assumptions and model various heave scenarios. Once the excavation phase is completed, the data will be used to design heave mitigation measures, using engineered materials and different compaction level tests. 

Eiffage Kier’s DIGGER concept

The site is also a real-world test for Eiffage Kier’s ‘DIGGER’ concept, which stands for digital graphical earthworks reporting. It uses 3D machine control for the digging and payload technology to measure material excavated, which is then tagged using in-cab controls.

The aim is to optimise performance of the load-and-haul fleet and the progress of grading and compaction operations. This is monitored through regular productivity alerts, such as for under or over loading of trucks, while other data is generated on machine performance and health, fuel use and carbon emissions.

David Lowery, executive director of Eiffage Kier, explains: “DIGGER is all about taking a step back and looking at every little bit of data that is created and captured for the project. It takes into account the ability to capture and process data now and the flexibility to adapt to new data inputs as future innovations are created, turning data into useful real-time information.”

DIGGER has been developed by Eiffage Kier with Caterpillar dealer Finning UK & Ireland, a project which began when the JV bid for the HS2 contract in 2015.

Blackwell’s six Caterpillar 745 ADTs have been fitted with GPS and payload monitoring technology

Ian Stewart, general manager of performance solutions at Finning, says: “We knew the challenges Eiffage Kier would be facing with delivering their section of the HS2 project, with earthworks volumes of up to 32 million cu m of cut and fill for its 80km section.”

Finning’s solution, a digital platform called my.finning.com, aims for a new level of operational performance, says Stewart.

“Sitting in the cloud and built around Microsoft Azure software, the platform was purposely built in a modular format, so it could be added to over time,” he explains. “Because we used Microsoft cloud technology, we were able to make it simple to use and easy to access from lots of connected devices.

“The system pulls in data from lots of different sources, to create insight and operational context for the end user, to help them make adjustments and improvements to operations.”

How the system works

The process starts with the creation of a digital 3D model, using Trimble Business Center software, supported by the Trimble Tilos project planning software. The systems manipulate data received from the earthmoving machines, drone flights and other surveying equipment, to help surveyors and engineers understand what has been dug, when it was dug, where the material went and how it impacted the overall schedule.

The data is then used to create digital layers of each week’s progress that can be overlaid to show an ‘as dug’ map of the site in less than 12 hours. This can then be compared against machine control data received from the machines, providing a check and balance for the site’s progress.

The my.finning.com platform takes all the information from these platforms and puts it into one place to provide a real-time view of the earthworks operation.

This feeds into the machine-controlled data required by the excavators and dozers on site for the next day. Utilising two-way communication, the machines receive and update the model through the GPS cloud-based Trimble Connected Community solution. With all of the systems connected, there is no possibility that excavator and dozer operators will be working on an old version of the plan.

Technology for operators

For the excavator drivers, additional in-cab technology is also provided, to understand what excavated material is going where on the site. This means each bucket loaded into an ADT needs to be tagged. This is particularly important for the wider project when it comes to the traceability of any contaminated soils that need to be remediated.

Finning integrated Trimble Loadrite software into my.finning.com. This uses an in-cab touch button control to identify the type of material the operator is loading. This data is matched with the GPS location of the truck being loaded. The load is then tracked along the haul road until the material is dumped, with a location reference for each load. Each truck and excavator also has onboard payload monitoring, so the volume of earth moved is calculated automatically.

Patrick McClure, Finning’s perfor-mance solution consultant, says: “My relationship has changed with the operators. Having met them all and shown them the data I get from the machine, we are now working together as a team to keep the machines healthy and performing to their maximum capability.

“This teamwork has continued as we have been introducing the new Cat Inspect app, which is a smartphone application that can help them carry out daily checks on the machine. They can log any issues they have with their machine and even take pictures of any damage or component wear. By being able to make general notes, they can also give me their thoughts on any slight changes in machine performance or responsiveness.”

“A great example of this was spotting a simple hydraulic leak, which was caused by a worn hose. By having the operator feedback to us that the machine had changed in performance, we checked the machine and found the problem, avoiding a big oil clean-up, longer repair and machine downtime.”

Data from machines, models and drones is also combined with localised weather reports to create a ‘delay register’. Everyone with access to the system can look at daily and historic data linked to weather conditions and what happened on site, so the team can spot trends and plan for delays.

So when it comes to work in awful weather, site managers in the future will be able to weigh up the costs involved with productivity losses, potential excessive wear on machines and increased fuel burn, and safety, to see if it pays to work on those days.

Using drones for site surveys

Three separate flights are required for the weekly survey of the 23ha Southam site

The Southam site is surveyed every week by drone to check the earthworks progress.

This can be appreciated by taking a drive round the site in an adapted 4×4, with sophisticated drone equipment. The vehicle also has its own Trimble GPS receiver on the roof and a Trimble Siteworks tablet in the passenger seat. With this technology, it is possible to view the live earthworks model from any location on the site, using a colour touchscreen display to change perspectives.

Drone flights require two operatives: a spotter and a controller. As birds of prey, which are known to attack drones, are present at the Southam site, the spotter on the Eiffage Kier site needs to keep a close eye on their movements.

When conditions are safe, the drone is programmed to fly over the whole site, mapping the dig area and two stockpiles, for topsoil and subsoil respectively. At 23ha, this site is so big that the drone has to make three separate flights to complete the survey.

Once the weekly survey flight is complete, the drone data is uploaded into the Trimble Stratus Drone surveying platform, which helps surveyors and project managers visualise the project on a week by week basis.

The team are currently achieving 18mm accuracy with the drone data.