Among the development trends in software and data services to the geotechnical sector of tunnelling, the topic of how to achieve better interfaces in the digital sphere is emerging as a prime area of focus. In terms of products, and in one area of classic challenge in civil engineering – the soil-structure interface, Plaxis has introduced new software: the Geo-Structural coupling tool which works with its Plaxis 3D program.
Bentley notes that asset tagging of boreholes is a coming feature among its suite of software offerings, resulting from rising construction industry expectation in the era of Building Information Modelling (BIM) and greater power and flexibility of computing solutions for the construction sector.
An important aspect of what the software can achieve, though, is how it can take data. Consequently, a perennial but increasingly important topic of discussion and effort is data formatting and what can be done to improve it further. The data format topic was the focus of a conference held by The Association of Geotechnical and Geoenvironmental Specialists (AGS) in late September. The event took place as it celebrated just over 25 years of making its AGS digital data transfer format (now in its 4th version) available to the construction sector for ground information management.
Speaking to Tunnels and Tunnelling at the conference, Shawn Sismondi, a senior geotechnical engineer with Laing O’Rourke and Ferrovial JV (FLO JV) on the central contract of the 25km long, super-sewer Tideway project, in London, said: “I would love to see a non-proprietary format to transfer asbuilt geotechnical construction data for tunnels.”
The possibilities around interfaces also gives rise to pooling data into larger databases, held by others, to form regional stores of geological and geotechnical intelligence as a resource for future infrastructure developments. Among a number of such projects, UK software developer Keynetix is working with the British Geological Survey (BGS) on some possibilities for pooling data.
STEPS IN SOFTWARE
Jasper Van Der Bruggen, sales manager North America for Plaxis, tells Tunnels and Tunnelling that the North American market for geotech and tunnelling software “is steadily growing, mainly due to new companies and offices joining this market.”
He adds, as a general statement, North America is late in the widespread acceptance and use of advanced software programs. Therefore, designs in North America tend to be over-conservative, leading to unnecessary high construction costs. Using advanced software programs can optimise designs and, therefore, save considerable costs.
He says there are widely varied experience levels among those using software which feeds into the many targets and objectives of developers. He says that, on one hand, there are new users starting to use software or numerical modelling, while on the other hand some very advanced software users push the envelope, such as developing highly complex 3D models.
To help meet increasing calls for even more powerful software capabilities, Plaxis is developing more interoperability for its Plaxis progam. Its latest 3D version is capable of exporting CAD geometry via the user interface, which Van Der Bruggen says is useful in BIM workflows or even 3D printing. Plaxis has also introduced its Geo-structural coupling tool to work across both Plaxis 3D and SAP 2000, a program widely used in structural engineering. The company says it’s the first commercial software tool of its kind, able to bridge structural and soil mechanics models.
Van der Bruggen says the market response has been “positive and enthusiastic.”
Plaxis 3D is among software programs used by Norwegian engineering consultancy, Multiconsult. Tunnels and dams engineer Bruce Ashcroft tells Tunnels and Tunnelling that the program is used for its underground seepage and 3D analysis. The consultancy also uses Rocscience products, including RS2, Unwedge and Rocdata.
Another program available is Itasca’s FLAC3D, a numerical modelling tool for geotechnical analysis. At Version 6.0, the program allows for explicit continuum modelling of non-linear material behaviour in 3D.
WORKING TO INTERFACE
Geotechnical interests are pushing for greater ease in data sharing, and so get more leverage from software systems and therefore more speed and efficiency in design and construction operations. Discussions are taking place on a number of fronts.
BIM
In the era of BIM and ever cheaper and more powerful computing power, the desire to get more out of IT is only increasing – as are expectations and conversations to be able to do so. Such dialogue has led to Bentley to be introducing asset tagging for boreholes, treating them only as objects rather than historical geotech data points in themselves, Tunnels and Tunnelling learned. The result is boreholes would not hold data locally, as the risk of being superceded, but as objects would call down the latest collected, and always-up-to-date, information from the central database.
While BIM is framing the context of conversations, Plaxis’ Van Der Bruggen says the movement doesn’t seem to be a game-changer, so far, in the geotech sector. However, he expects interoperability to gain even more importance, with or without BIM.
Interoperability is a key part of the message in BIM, which Stanford University professor Martin Fischer says is as much about process and communication as technology. It would then enable the widest choices of tools for concurrent design development, and the continuing evolution of geotech information from site investigation (SI), allowing data to move freely in non-proprietary formats. Such data would be easily usable in a team member’s own choice of software for a project – unless prescribed otherwise by the project owner or project manager.
AGS for SCL tunnels
While the AGS format is a spreadsheet listing and therefore highly readable digitally, the data would need additional formatting to be usable by software systems to help plan or control excavations on tunnel projects.
The ideal would be to have such a common data format system to be easily taken up by any software platform used in the underground space sector.
To that end, in part, research is getting underway on part of the Tideway project in London to look at taking AGS format forward for tunnelling.
“I’ll be undertaking the development of an extension of the AGS format specifically for SCL tunnels,” Sismondi tells Tunnels and Tunnelling.
The aims is to achieve better understanding of the lining behaviour, shotcrete fallout and SCL interaction with the ground, he says. Information will be inputted on tablets and reviewed during shifts, helping further with quality as well as health and safety. The system would enable quick evaluation of SCL data versus geotechnical data, and the pre-construction model would be updated with the as-built construction data.
“It becomes very important having data sets in a common database and with a common format,” Sismondi told delegates in his presentation to the AGS Geotechnical Data Conference. The contractor hopes to share what is learned across the entire Tideway project.
The initiative aims to take forward that discussion through making a recommendation to the AGS committee to consider around mid-2018 after a paper is produced on lessons learned. Discussions on the possibilities were held earlier this year.
The SCL works will be undertaken at the Kirtling Street launch shaft in advance of the TBM launches. The work is being jointly funded by FLO JV and the Tideway client as part of the project’s Innovation Forum. For the task, the contractor will be using Bentley software products, including ProjectWise, MicroStation and gINT.
Pooling together
In another aspect of interfaces, Crossrail drew upon pooled data held by BGS to complement its own SI probing, and held the information in the AGS format, and which was stored in the project’s Asset Register. After the project, the client plans to send all its geological data to the BGS, further contributing to the pool of subsurface knowledge of London and to benefit later project development. The Tideway project and so many others draw upon the data held on London by BGS.
BGS is also part of a research initiative – BIM for the Subsurface – along with Atkins and Keynetix, the latter using its HoleBase software platform along with plug-ins from AutoCAD. Keynetix’s technical director, Gary Morin, briefed the AGS conference on the research project. The research initiative has had three core steps: the first two being data access and cloud service hosting, respectively, and allow the research partners to collaborate and share information; and, the third step is 3D geological modelling using AutoCAD Civil 3D.
The data pooling system used HoleBase to upload data in AGS format to BGS databases for sharing with others, as is the core aim. Keynetix notes that the system developed by the partners is independent of its software platform. A further aspect of the research was in the 3D model visualisation, and that is part of an interesting, wider topic around ways of conservatively utilising geotechnical data collected for any project, anywhere (see box).
To close the AGS conference, Garry Baker of National Geoscience Data Centre of BGS promoted the possibilities around pooling of information for its Open National AGS Data Store. He said the NGDC is trying to hold the geotechnical data ‘for the longer term,’ which in effect would be helping to hold some description of the “natural capital” stock of what is known of the geology in an area, based on prior ground investigations.
Here, the interface is with time, the benefits to be gained by a more collective engagement trend are to be found by data owners and users opting to pay-itforward, and see cumulative shared gains to society, and industry, down the line. It was recognised in Q&A, though, that questions remain over turning over data and to what degree, especially as such pooling is not mandatory.
