High Speed 2 is pushing for change in the geotechnical sector by making site investigation work more digitally focused.
High Speed 2 (HS2) project promoter HS2 Ltd is using its power as Britain’s biggest infrastructure client to push the UK ground investigation sector into the 21st century.
The geotechnical sector is mired in manual processes, for example borehole logging is often managed in Excel spreadsheets and reports are produced in PDF formats.
Change for the good
HS2 Ltd wants to change this lag in the industry not only for the good of its project, but for the UK as a whole.
“The HS2 geotechnical investigations are being delivered by a third of the ground investigation industry in the UK,” says HS2 Ltd ground investigation programme manager Steve Reynolds.
“We’ve got nine of the biggest contractors, all the major players and a few small and medium-sized enterprises (SMEs). We’ve got 20 of the geotechnical labs who are producing data for us.
The HS2 geotechnical investigations are being delivered by a third of the ground investigation industry in the UK
“We’re in a position where we can change the industry to make it more efficient and better in the way it does things.”
In any construction project, a large part of the risk generally lies in the ground.
Ground which is not as strong as it is assumed to be, or buried structures which are not marked on as-built drawings all present a risk which, if not mitigated, can prove costly at later stages of a project.
The more information which can be gleaned and fed into the design at the earliest possible point, the smoother a project will generally be.
Part of what is very different for the HS2 ground investigation is that we’ve put a lot of emphasis on the ground contractors themselves
Despite the long HS2 timescales, the window for collecting ground information for 52 work packages worth between from £250,000 and £6M, is actually surprisingly short, says Reynolds. Access to land to conduct the tests had to wait until Royal Assent for the HS2 enabling legislation was granted.
But with a design deadline looming, HS2 Ltd decided to radically change the way it managed the data to ensure that it could achieve the sheer volume of investigations required.
Minimising site investigation impact
Reynolds says the need to minimise the impact of the site investigation works on land owners meant HS2 Ltd had to implement a “one shot” approach – collect the maximum amount of data in one site visit. To obtain the data faster, it is pushing the industry to go digital.
“What we’ve done that’s substantially different is we’ve started putting things in a digital format from the start. We’ve started logging data in AGS so we have a digital archive.”
The AGS format, set up by the Association of Geotechnical & Geoenvironmental Specialists, is not new, but HS2 Ltd is the first to programme to use AGS version 4 on a project.
The format provides a way of inputting geotechnical data directly into the building information modelling (BIM) system, bypassing the paper trail.
Reynolds admits the approach has been a bit of a learning curve for the industry, but now it is over its teething troubles and the feedback is that the contractors involved would not go back.
Rapid data input
The speed with which the data can now be inputted into the system means the civil works contractors are getting the geotechnical information at a far earlier stage of the design process than would previously have been possible.
At present, updated information is given to the contractor every two weeks, but the project wants to go further than this.
The site investigations for phase 1 were due to conclude at the end of 2017. But the project client is already developing plans for improving the system for phase 2 which will have to collect double the data collected for phase 1.
Reynolds says the project wants to push further and move to more advanced versions of the AGS system. He also wants to accelerate the delivery of the data to the contractors and is looking at replacing the need to email data with a system where it can be inputted into a common data environment.
“We’re looking at taking live data from rigs on site, so that we can start dynamically managing the ground investigation from a common data environment.
“It’s digital, but it’s still a manual process with someone inputting the numbers from a PDF,” he says.
“We should be getting to the point where we start auto-populating the data, if then we can take the geotechnical engineers’ brain power to do the good stuff rather than just the data entry into a spreadsheet.
“That’s why we’re pushing as that’s how we make it cutting edge and an exportable business for the UK.”
The organisation is also pushing the geotechnical contractors which are carrying out the work to take on more of the responsibility for the data.
Using ground contractors’ skills
“Part of what is very different for the HS2 ground investigations is that we’ve put a lot of emphasis on the ground contractors themselves and to use the expertise they’ve got rather than seeing them as just a sub-contractor who drills holes and does the mundane logging.”
Pushing them in this way has upskilled the organisations, improved their health and safety planning and technical input into the programme he says.
HS2 Ltd is also looking to pass on the lessons it has learned to other major clients and has already had meetings with some, such as Heathrow Airport Ltd, to extol the value of going digital early.
One of the things Reynolds says HS2 Ltd is looking at is whether a consultant is still needed to sit and manage a project when subcontractors have become more highly skilled.
As a legacy, the data collected is being handed over to the British Geological Survey, increasing the number of records it holds by two and a half times.
A full suite of tests is being carried out as part of the ground investigation works, says HS2 Ltd ground investigation technical specialist Graham Dowlen.
Trial pitting; windowless boreholes for shallow ground; percussion works; cable percussions with follow-on rotary percussion works; and rotary works from ground level are all being used on the project. In addition he says sonic drilling and down hole geophysics are also being used.
Dowlen says because of the high degree of accuracy to which the logging is being carried out, HS2 Ltd has been able to understand the ground in considerably more detail than on previous projects.
Previous data for vast areas of the country does not exist, he says, and as such it has been found that the Chilterns are actually heavily faulted. The ability to give this information to contractors at an early stage of design is crucial to cutting the risk and construction cost, he says.