Article Data Management

AGS publish roadmap for AGSi

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AGSi is a transfer format for ground model and interpreted data, created and maintained by the Association of Geotechnical and Geoenvironmental Specialists (AGS). It was launched, as a beta version, in November 2020 with a further update issued in November 2021.  Documentation for AGSi can be found here.

AGS have now issued a roadmap for the future of AGSi. This identifies the processes and actions required to get AGSi ready for its first formal release (version 1.0), before going on to look at what needs to happen to achieve the ultimate goal of establishing the use of AGSi in our industry, for the benefit of the industry.

The roadmap identifies a steering group that has already been formed and the plan is for an early adopter user group to develop out of this. If you are interested in joining the steering group or getting involved as an early adopter, then please get in touch with us.

AGS is aware of other international initiatives relating to geotechnical data and models. In particular, AGS is an active participant in the OGC Geotech Interoperability Experiment project that was launched in early 2022.

The current intent, reflected on the roadmap, is for AGSi version 1.0 to be formally launched at the The Geotechnical Data Conference, hosted by AGS and to be held on 1 December 2022 at The Burlington Hotel in Birmingham.  Hope to see you there!

Article Business Practice Contaminated Land Data Management Executive Geotechnical Instrumentation & Monitoring Laboratories Loss Prevention Safety

UK Specification for Ground Investigation (third edition) – Now Available for Purchase

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We’re pleased to announce the launch of the third edition of the UK Specification for Ground Investigation – also known as ‘Yellow Book.’

This latest edition of Yellow Book has been revised by an industry working group led by the AGS, and provides best practice guidance for designing and executing good-quality ground investigations that will allow clients and land developers to manage the risks and help to reduce project time and costs.

Ground investigations are an essential part of the design process for any structure and land condition assessment. They are used to validate the ground model, assess ground risk, obtain geotechnical data for design and geoenvironmental data for the assessment of the risk to human health. Yellow Book will help to protect construction professionals and clients, from unexpected ground conditions during construction. Updates in this edition take account of changes to health, safety and environmental legislation, numerous new British Standards and industry guidance.

The UK Specification for Ground Investigation is essential for all ground practitioners involved in ground investigation, including geotechnical engineers, engineering geologists, environmental scientists, instrumentation and monitoring specialists, hydrogeologists and geophysicists, as well as specialists in other disciplines involved in specific investigations.

To purchase Yellow Book, click HERE

Want to know more about the new edition? Then join Julian Lovell, Mathew Baldwin and Stewart Jarvis, three of the main authors of the third edition, for a free webinar on 23rd June 2022 at 11am. The trio will set the context for the revision, explain the changes made and reasons behind them and provide details of how the new Specification document should be used and the major areas of change required by industry to conform to current good practice.

To register for the webinar, or to watch the replay (post-event) click HERE.


AGS Magazine: May 2022

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The Association of Geotechnical and Geoenvironmental Specialists are pleased to announce the May 2022 issue of their publication; AGS Magazine. To view the magazine click here.

This free, publication focuses on geotechnics, engineering geology and geoenvironmental engineering as well as the work and achievements of the AGS.

There are a number of excellent articles in this issue including;
AGS Annual Conference @ Geotechnica 2022 – Page 4
AGS Geotechnical Data Conference – Page 9
AGS Loss Prevention Guidance Photography Competition – The Results – Page 12
AGS Webinar Updates: Brownfield Regeneration and Degree Apprenticeship in Geoscience – Page 16
Serviceability Limit State and Sustainable Shallow Foundations Design – Page 24
Driving at Work: A look at the guidelines – Page 30
BS8661 Geotextiles: Guidance for specification for basic separation and filtration functions – Page 36

Plus much, much more!

Advertising opportunities are available within future issues of the publication. To view rates and opportunities please view our media pack by clicking HERE.

If you have a news story, article, case study or event which you’d like to tell our editorial team about please email Articles should act as opinion pieces and not directly advertise a company. Please note that the publication of editorial and advertising content is subject to the discretion of the editorial board.


AGS Loss Prevention Guidance Photography Competition – The Results

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In January 2022, the AGS launched their third photography competition, this time to source a suitable cover for the 2022 edition of the AGS Loss Prevention Guidance.

49 entries were submitted, each covering a range of topics across the geotechnical and geoenvironmental sector including site work, landscape imagery and machinery shots.

AGS Loss Prevention Working Group Leader, Hugh Mallett, along with five members of the Loss Prevention WG, Jo Strange, Peter Plumpton, Sam Bevins, Syd Pycroft and Chris Hoskins took on the challenging task to judge the images by scoring across five criteria;

  • Originality
  • Composition
  • Colour, Lighting, Exposure and Focus
  • Overall Impression, Impact and Visual Appeal
  • Suitability for Loss Prevention Guidance

Four images were shortlisted, and we’re pleased to announce that Kaya Dearnley of SOCOTEC was the overall winner of the competition and won a luxury Fortnum and Mason Hamper.

Our three runners up, who each won a bottle of Champagne are Hope Murray-Golas (Concept Engineering Consultants), Simon Ruddlesden (Ruddlesden Geotechnical) and Kevin Privett.


Kaya Dearnley, SOCOTEC

Image description: A Comacchio 205 positioned on a beach groyne in Bournemouth. It was taken as the sun was beginning to set over the sea after a long day of drilling.



Hope Murray-Golas, Concept Engineering Consultants

Image description: Offshore wireline rotary drilling for a new airport scheme.



Simon Ruddlesden, Ruddlesden Geotechnical



Kevin Privett

Image description: On the former A625 road crossing Mam Tor landslip in Derbyshire.


The AGS would like to thank all those who took the time to enter the competition. The overall standard of entries was extremely high, and the judging panel found the task challenging in shortlisting the top four entries.


Q&A with Roger Clark

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Full Name: Roger Clark

Job Title: Director

Company: Marlowclark Consulting Limited

Roger is a Chartered Civil Engineer, SiLC and NQMS SQP with 54 years of experience. He has represented AGS for the last 14 years on the SiLC PTP and is the AGS Director on the SiLC Board, having chaired the Board for 2 years to the end of last year. Roger is a SiLC Assessor and also assists with the preparation of questions for the SiLC exam. He is an honorary member of the AGS Executive.

He was previously the Senior Director of CL Associates (CLA), which became the Geoenvironmental Consulting Division of ESG, now SOCOTEC. He had overall responsibility for management, business development and the technical capability and quality of the division including the direct control of certain major projects.

What or who inspired you to join the geotechnical / geoenvironmental industry?

The subject at university that inspired me most in my civil engineering degree course was geotechnical engineering, or soil mechanics as the topic was called then. On nearing the completion of my degree, it therefore seemed logical to apply to Soil Mechanics Limited (SML) and I was fortunate to be offered a job. In the early years I had the privilege of working with or under the guidance of Noel Hobbs, Bryan Skipp, Alan Meigh and Ken Early, all of whom have been or are recognised for knowledge, skill and quality. This gave me the best grounding for my career that I could ever have wished for. At that time geoenvironmental was not really recognised as a specialism. It was only much later, as the manager of the SML Consultancy Division, and in the early stages of the industry waking up to the need for services in contaminated land and waste management, that I was involved in the setting up of CLA.

What does a typical day entail?

I am now substantially retired from professional work with the exception of providing whatever input I can to SiLC and AGS. I am Chair of my local parish which gets me involved in community matters, liaising with the County Council and District Council to achieve whatever improvements I can to our local amenities.

Therefore, a typical day for me can be very varied, sometimes relaxed but at other times trying to stuff more into the day than will fit. I switch from sitting in front of my computer preparing draft SiLC procedures or guidance, exam questions, assessing candidates, articles for the AGS e-magazine, and preparing for and attending PTP and Board meetings, etc to dealing with parish matters to family to gardening and house maintenance. You would be forgiven for thinking that I can control my own time choosing what I do and when. That is my objective but never seems to happen. Like all of you, having stuck my hand up, I am subject to the demands that come at me from various quarters.

Are there any projects which you’re particularly proud to have been a part of?

There are three in particular, the first being the Nghi Son Refinery in Vietnam which is about 250 km south of Hanoi. Site clearing for the project broke ground in 2008 with construction beginning in 2013. Production commenced in 2018. Working with Foster Wheeler, I led a team within CLA to supervise site investigation and to design suitable foundations for heavily loaded structures on about 60 m of soft marine sediments. Quite a challenge, but the team showed real skill and expertise to come up with an innovative foundation solution.

The second was a long-term leakage of fuel from a filling station on a promontory of fill at the edge of the River Nene floodplain. Slippage of the fill had ruptured fuel pipes and fuel had leaked downslope into the gravels of the floodplain. We designed a scheme involving extraction pumping, surface skimming and activated carbon filters. This interesting project involved both geotechnical in respect of determining the cause of the slippage and geoenvironmental in respect of the clean-up. For me, a really interesting aspect was providing expert witness in the High Court in London which involved four full days of giving evidence and being cross-examined. I found the court proceedings fascinating and really admired the ability of our QC to grasp a multitude of information, particularly slope stability analysis which was a completely new subject to him.

The third project was the Sydenham Gasworks near Crystal Palace which again involved a combination of geotechnical and geoenvironmental input. This one sticks in my mind not just because I was involved over a 17 year period but also because of being involved throughout from the time that it was a smelly eyesore (and in spite of that there had to be a public inquiry at which I gave evidence), to now providing a local facility as a retail park.

What are the most challenging aspects of your role?

I think in this context I should talk about my previous role with ESG. There was a need to balance the business requirements such as budgets, marketing and management with the need to keep technically up to date in both geotechnical engineering and contaminated land / waste management and to manage projects. Both of these sides to my role usually demanded more time than could be given, so the challenge was to deal with both and still get home for supper before it got thrown in the bin. The bigger challenge was that for my long-suffering wife, Janet, who had to put up with me.

What AGS Working Group(s) are you a member of and what has been the recent focus?

Apart from the AGS Executive, I attend the AGS Contaminated Land Working Group. My recent input to this has been the writing with Louise Beale of the Clients Guide to Geoenvironmental Reports and also aiding in the preparation of the Training Paths for Ground Practitioners – Geoenvironmental Specialists.

Why do you feel SiLC is important to the industry?

It is an indicator that senior professionals in our industry have gained a level of knowledge and expertise that has been judged by their peers to be at a high level. For many, it is considered to be a natural part of their career development demonstrating to their clients, regulators with whom they interact, their colleagues and themselves that they have achieved this capability.

As many will know, SiLC also assesses suitability for someone to be on the NQMS SQP Register. Improving quality has to be the objective of everyone in our industry and these schemes are part of the process of achieving that. SiLCs and SQPs are bound by a strict code of conduct which is another factor in demonstrating their standing and ability to provide sound advice which is tansparent in identifying any uncertainties and the implications of the conclusions.

What activities are SiLC working on at the moment?

One of the things that SiLC can do is to assist in developing knowledge and gaining recognition of significant issues that face the industry. The Annual Forum is part of this and also the presentation of webinars, the next one being ‘Regeneration of Historical Landfill Sites – Multi-Stakeholder Perspectives’ on 30th June, which will examine some of the problems currently being experienced. SiLC have also written to various Government departments and the EA regarding this.

One of the significant issues facing us is the reduction that has been seen in the number of young people joining our industry for whatever reason, be it a reduction in the number of suitable university courses or simply because we do not advertise ourselves enough. Having worked in the geotechnical and geoenvironmental field for a considerable number of years I, like many others, have thoroughly enjoyed it and benefited from a very varied, interesting, and often challenging career. Looking back, I am very glad that I chose the path that I did. The SiLC Affiliate Scheme is intended to encourage young people to join the profession, and a short promotional video has been prepared to encourage them to do so. The task now is to get as many people as possible to watch it.

SiLC are part of the NQMS Steering Group and having carried out an audit of the scheme to determine where changes or improvements might be needed, one of the next tasks is to expand the NQMS documentation to include permitting and to modify some of the existing documentation to incorporate the results of the audit.

What changes would you like to see implemented in the geoenvironmental industry?

More endorsement of schemes like SiLC, SoBRA and NQMS by government departments. Some progress has been made on this in respect of the NQMS in a meeting between the Steering Group and DLUHC which will hopefully lead to some firm commitments.

Continued recognition and increased understanding of the causes of climate change including the effects of what we do as an industry. There is so much more that can be done to reduce carbon emissions for example, including how we remediate sites, how many vehicle movements are involved, the extent to which the ground is disturbed and hence releases stored carbon, the emissions from any treatment processes that we use or recommend, etc. We need to educate our clients in this respect, presenting them with sound reasoning for environmentally friendly schemes rather than just following traditional thinking. Many clients are already on board with this, but some unfortunately are not. Thinking back to the Nghi Son Refinery, their product is the cause of a large part of the problem which can’t be mitigated by the plant itself, but it has to be said that in the early stages of the project the owners did take on board a number of mitigating measures to reduce the local environmental impact of the plant being built.

I would like to see more overall involvement of geotechnical and geoenvironmental specialists in project teams at a decision level. All too often, site investigation is procured, and then other professions make the fundamental decisions. There needs to be more continuity with geotechnical and geoenvironmental specialists being involved throughout the investigation, design, and early construction stages of a project. The projects in which we have been involved throughout the process have always ended up running more smoothly, with less delay and often more cost effectively, with the prospect of unexpected costs being minimised by prudent spending at an earlier stage.

Article Data Management

Release of AGS 4.1.1

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The AGS has long been associated with the method of exchanging ground investigation data.   The AGS data transfer format has evolved over the last 30-year, through 12 versions, since the release of AGS 1 in 1992.  In December 2020, AGS 4.1 was released, the culmination of decade’s worth of feedback and response from the previous version.  AGS 4.1 contained substantial enhancements to the data dictionary and represents the efforts of individuals from a wide variety of specialities within the sector.


After AGS 4.1 was released, it became apparent that further minor enhancements could be made to aid users.  The Data Management Working Group has, therefore, continued work since the December 2020 release and now AGS 4.1.1 is available for download from the AGS website.

Note that AGS 4.1.1 supersedes AGS 4.1.  The original AGS 4.1 document remains available for download but should only be used for academic purposes. AGS 4.1.1 is the latest version.

A full list of the changes in AGS 4.1.1 over the 4.1 version can be accessed on the AGS website ; a  registered login will be required.  The changes can be broadly summarized as follows:

  • A small number of data types have been adjusted to better serve their intended purpose. These are mainly in the CTRP, FGHI, RSCH and RUCS groups,
  • The removal of some obsolete and erroneous headings (GCHM_RDEV, PMTD_SEQ, WGPG_LIM and WGPG_ULIM),
  • Description changes to clarify the intended purpose of fields,
  • Adjustments to examples to aid consistency with the recommended data type. Examples have also been added to various headers,
  • Some headers now have a recommended unit defined where they did not have one specified,
  • Inconsistencies between the published Electronic Transfer of Geotechnical and Geoenvironmental Data document and the listings on the website have been addressed,
  • A total of 387 minor adjustments from AGS 4.1.

Members of the Working Group have also been involved in the development of the AGS Validator, which will replace the current versions.  In particular, the Working Group would like to acknowledge the efforts of Asitha Senanayake (Fugro) for his help in its development.  A beta version of the validator is available for download and can be used in line with the conditions outlined on the webpage.

The AGS Validator is a tool for checking AGS 4.1.1 files for compliance with the transfer rules and is associated with the AGS trade body rather than any specific software provider.  It also checks for compliance of earlier versions AGS 4.1, 4.0.4 and 4.0.3.  The AGS Validator does not check for accuracy of the data, only compliance with the rules. The Validator will also export AGS data to an Excel .xlsx spreadsheet format.

Many users of AGS 4.1.1 will still find the recording of the original launch webinar (08/12/2020) helpful due to the iterative nature of the changes.  Additionally, the documentation retains (and has expanded on) much of the specific guidance for many of the groups.  Users of AGS 4.1.1 will, hopefully, find these resources very helpful.

Questions and feedback are always welcomed from registered users on the discussion forums as this helps to ensure AGS remains relevant to the needs of our industry.


Ground movements on Underpinning – An Update from the Geotechnical Working Group

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In April 2021, the Geotechnical Working Group issued an article titled Ground movements on Underpinning – A problem with data?, with the objective of launching a discussion to try and better understand the magnitude of ground movements that can arise due to underpinning and the construction of small-scale basements, and how  ground movement data recorded as part of the construction process can be used to establish a robust framework for the analysis and prediction of potential movements on new projects.


Since publication of the article, an Underpinning Focus Group has been formed by interested members of the Geotechnical Working Group. The Focus Group has been working closely with the University of Portsmouth to facilitate an MSc project, using data from a series of basement excavations within central London, which was completed towards the end of 2021 and identified some issues likely to be common to many projects:


  • Often buildings involve a mixture of underpinning and piling, and this modifies the movement in different ways.


  • Some buildings have inherent problems before construction starts and may already have ground movement problems before a new basement is excavated.


  • There is normally no published ‘post construction report’ to say what went according to plan and what changes were made during the construction, unless an article is published, making it difficult to assess what learnings were made.


In general, the study found that there was a good level of agreement between predicted and actual movements and was able to make the following recommendations:


  • Close coordination between the geotechnical / ground investigation consultants, structural engineers, movement monitoring survey companies and the construction companies is important.


  • Identify and confirm the geotechnical properties, depth and influence of superficial deposits, such as river terrace deposits, brickearth and the weathered London Clay within the area of the proposed development to enable the development of a ground model that accurately reflects the ground conditions that can then be used in any subsequent design of the proposed basement structure and analysis of potential ground movements.


  • Accurately assess the state of buildings and infrastructure in the vicinity of the excavation site prior to construction.


  • Ensure the ground and building monitoring survey targets are in-place before any construction, ground loading or demolition work commences, as it is important to establish a baseline of background noise, vibration and any other ground disturbance.


  • Make provision for monitoring sensors to remain in place once construction is complete to provide data on the long-term response of the ground and surrounding structures to basement construction.


  • Although it is generally considered that the deepened foundations provided by basements should make the overground structures more stable, the subsurface geology, excavation methods, construction techniques, and the quality of workmanship, can all have different impacts on the severity and extent of ground movements affecting adjacent buildings and structures.


Following completion of this initial pilot study, three more MSc projects are presently in hand and due for completion at the end of this academic year, with the students working on the modelling aspects of the problem using real data from basement excavations in London, which, it is hoped, will lead to further detailed analysis and ultimately the establishment of a research group to continue the work that has been started.


In the long-term, the Underpinning Focus Group is looking to facilitate the collation of case study data and are presently working on ideas for a suitable on-line system to allow members and other interested parties to submit data and share their experiences, which, in time, can hopefully be used to generate guidance through suitably reviewed research of the case studies. In the meantime, if any readers of this or the previous article have data or other personal experiences that they think might be of use or would like to become actively involved and contribute to these discussions, then please contact the Geotechnical Working Group (, who will be more than happy to hear from you.

Article Safety

Driving at Work

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In 2020, a government task force estimated that a third of all road traffic accidents involve someone at work. This accounts for potentially 20 fatalities and 250 serious injuries per week. Yet the rules on drivers’ hours, vehicle weights and licence requirements can be difficult to apply to specifics within your fleet. This article discusses how the ground investigation (GI) industry fits into the national legislation and how to ensure you and your colleagues are adhering to the law.

From 16th December 2021, the laws around towing a trailer changed to allow more licence holders the ability to tow without undergoing additional testing. This change was a government reaction to the HGV driver shortage, in an effort to free up examiner time, and whilst many individuals and organisations will be able to make the most of the new rules, it runs the risk of adding more uncertainty to an already misunderstood set of laws.

What the legislation tells us

A simple rule of thumb is if the sum of the vehicle and trailer weight is less than 3.5 tonne, then the driver would probably fall under domestic drivers’ rules. The main restrictions under these rules are a limit of 10 hours total driving or 11 hours duty time per day. There is a list of exemptions to this categorisation, so it’s important to correctly identify your vehicles along with the intended activities.

If your vehicles and/or trailer weights are over 3.5 tonnes, then EU rules can apply (with some exceptions). This will likely mean the introduction of tachographs within your vehicle cabs and potentially even operator licencing for your company. These are requirements used throughout the haulage and logistics industry to safely manage the operations of large goods vehicles across the continent. However, this can prove difficult to apply in the GI industry without the help of a transport manager or a competent person experienced with the level of compliance needed.

Many small-to-medium enterprises will have to make difficult choices of whether to use costly third-party couriers for their equipment mobilisations, or to fund both the training of employees and capital investment needed to comply. This will inevitably lead to instances of non-compliance, either consciously or subconsciously, when driving an overweight vehicle or to travel five hours to the next job after a full day on site.

Learning Lessons

Following several instances of rail workers being involved in road traffic accidents on the drive home after a night shift, new fatigue management regulations were adopted. This included recommendations on shift times per day and week, along with minimum rest periods and importantly, the time spent travelling to and from work. Employers are urged within the guidelines to ‘assess and control work related road risks in their operation’ as the travel time can ‘contribute to fatigue’. Possible solutions include providing nearby lodgings or safe transport, such as a taxi.

Requests from the Principal Contractors for staff location and travel times are subsequently commonplace for shift planning within the rail industry. Is it time for similar requirements to exist across the GI industry?

We all hear the stories of 4am starts for field workers in order to reach site for the inductions at 8am and/or getting home at 10pm on a Friday night, but with the alternative being weekend travel disrupting the work life balance and increasing costs, it’s easy to see why these practices have become the norm. If we’re going to ensure all workers attending our site have the right class of cut resistant gloves or the correct CPCS card for the plant their operating, should we not also check they haven’t driven 300 miles that morning?

Accreditation bodies such as the Fleet Operator Recognition Scheme (FORS) offer their members an opportunity to showcase their adherence to a high standard in terms of transport management and can be assurance to contractors that their supply chain invests in the correct practices. However, from experience, it is not straight forward.

What we can do

The ability to apply the legislation to the specifics of your own business is key, to shine a light on the grey areas we often find ourselves in, or in some instances look to put ourselves in. Given recent changes in licencing, it’s important to familiarise yourself with the current rules.

Firstly, identify and categorise your fleet to ascertain the specific restrictions of your vehicles when laden with equipment. Secondly, confirm the licencing and competence of the intended drivers. Then plan your work schedule accordingly to allow for at least the minimum breaks and driving hours as required by law.

Logistics have come a long way since the days of AA route planners. There are dozens of software packages available to help organise your vehicles, drivers, and their movements, and importantly, to ensure compliance. Many can be adjusted to suit your specific needs and are often scalable to help with the cost/benefit ratio.

Do not underestimate the importance of monitoring driving activities within your business. You can identify gaps in either driver or management competencies and take action to introduce safer practices. In the event of a work-related road traffic accident, a major focus of an investigation will be on the records kept; driver competencies, along with tachograph records or employee timesheets, help to establish not only how events unfolded, but also determine any unsafe practices. By monitoring, you are providing evidence that unavoidable exceedances of driving hours, for example, are recorded and lessons can be learnt.

Summary / Conclusions

The HSE Driving at Work guidelines make it clear that ‘on the road work activities and the risks should be effectively managed within a health and safety system’. This means imbedding policies and procedures within an organisation to manage the risks and associated measures.

Becoming a member of industry bodies such as the Road Haulage Association or Logistics UK, not only keeps you up to date with any changes in the law, but also enables you to call on experts for advice on how best to manage your fleet.

Managers and senior staff should lead by example. By having a thorough understanding of the legislation, good practices can be employed, demonstrating an expectation within the business. Investment in maintenance and training to ensure your fleet is safe and legal is also imperative. Further, good communication between management and field workers regarding shift patterns or fatigue, either with themselves or colleagues, as well as reporting any accidents, incidents or near misses is crucial to implementing a positive change.

Article provided by Chris Dimelow, Operations Director, Lankelma

Article Geotechnical

Serviceability Limit State and Sustainable Shallow Foundations Design

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With the Net Zero target initiatives set, shaping the future of the construction industry around a greener approach must be one of the main focuses of the sector. Although these fixed dates appear to be long ahead, data shows that significant changes must be made immediately and in great scales, to be able to cut the carbon emissions to the required levels. The consequences of failing to do so will have a significant impact on the future of our lives. The concern is that even with the recognized importance of this matter, the regulations for UK construction industry yet fail to formally incorporate and enforce the requirements for build to a net-zero emission performance at the current time.

Nevertheless, the industry is going through some changes to improve, predominantly within the larger firms that have the resources and the funds available to invest in greener solutions, although this is considered to be nowhere near sufficient.

Studies show that these efforts are vastly shifted towards targeting reduction of emissions by focusing on the operational carbon emissions and less by means of targeting embodied carbon emissions or reducing the net carbon emissions by offsetting practices. However, research indicates that in actuality, to achieve the Net Zero targets by 2050, a fabric first approach, focusing on the embodied carbon in combination with operational carbon footprint reduction is extremely vital (1). This approach would be targeting the whole life carbon emission footprint of a project.

As engineers we have a significant impact on projects’ embodied carbon emissions, through our design of every aspect and step. In the absence of enforced guidlines, it is our responsibility to target embodied carbon emission reduction by adopting a more efficient design and/or selecting the right materials.

This article aims to challenge our approach towards serviceability limit state verification of shallow foundations, in order to achieve a more sustainable design. This topic is considered to be of significant importance, because often the shallow foundation design is governed by the serviceability limit states, particularly where cohesive deposits are present within the influence zone of the foundation. An overly conservative design can lead to requirement for larger and therefore less environmentally friendly foundations.

Design of foundations generally involves both the geotechnical and structural engineers; and given the set industry Net Zero targets, they must fully appreciate that whilst some initiatives (such as Whole Life Carbon Approved Document Z (6), UK Architects Declare Climate and Biodiversity Emergency (2) or the RIBA’s climate change plan (3)) are merging to allow a more structured and regulatory approach, they must take immediate actions through design to implement the Net Zero Performance criteria.

We recognize that the design of a foundation must satisfy the ultimate limit state and the serviceability limit states.

The serviceability limit states of the foundations, assessed in form of settlement, as described within the current Eurocodes (5) are considered to be those concerning comfort of the users during use and the aesthetic of the structure, and it depends on both the total and differential settlements. Our approach to validating the serviceability limit state generally comprises assessment of the anticipated settlement of the ground due to the applied load against a total settlement limiting value and assessment of the differential settlements across structure foundations against a differential settlement limiting value, such that the serviceability limit state criteria described above is utilised.  On this basis, we consider that a greener approach can be achieved through two possible ways: first challenging the industry accepted serviceability limit state limiting values and second, the exploring available methodologies through which the settlement is estimated.  These are to, typically, be considered by the structural engineers and the geotechnical engineers respectively.

Nonetheless it must not be forgotten that a foundation is the point of interaction between the ground and structure and therefore a lack of communication between the two disciplines can often result in an overly conservative design.

The serviceability limit state limiting values, must be chosen based on a series of factors, as described within the Eurocodes (5), such as: the rate of ground movements, the type of structure, foundations and construction material, ground conditions, the mode of deformation, the structure function and the need to ensure that there are no problems with the services entering the structure. Therefore, with reliance on the Eurocode guidance, it is evident that the limiting values must be decided upon by consideration of the factors mentioned and based on the design requirement throughout the lifetime of the structure.

However, whilst the codes provide us with clear indication of what must be considered, their guidance provided on the actual limiting values are generic and limited. This should be considered as an opportunity for critical thinking to evaluate design and therefore to provide values reasonable for the requirement of each specific project. In addition, other guidance (such as Structural Engineer’s Pocket Book Eurocodes(7), allowing determination of a value based on deflection criteria of a structure in accordance with the Eurocodes) through consideration of specific criteria as listed by Eurocode, can be utilised  to assist with the limiting value determination. A review of the Eurocodes Next Generation, it is clear that guidance as such are to be provided more clearly with a better and more clear guidance on the limiting values, on the basis of a project risk/sensitivity assessment, which is what should in reality be undertaken by the engineers continuously. Though, even with the new guidance from the Eurocode Next Generation, a thorough evaluation of the requirements of design, must still be considered.

The question raised, for the time being, is that why guidance as such is not used often enough to give limiting values specific to the design of every structure, as opposed to using the set of generic values, considering that the effects of this value on the sustainable design of the foundation can be significant, particularly on larger scale projects with numerous foundations involved.  Therefore, it is important that prior to choosing a limiting value, that consideration is given to factors such as: importance of aesthetics, lifetime of the structure or use frequency. Of course, this requires a thorough understanding of ground movement and its effects on structure. In terms of challenging the design of serviceability simit states, from a structural engineer’s side, it can be challenged that by a better understanding of differential and total settlement concept, more thoughtful and possibly less overly conservative values can be used. This applies to even where the typical values are used for the purposes of design.

In addition to challenging the limiting values, the methods of estimation of settlement must be considered by the geotechnical engineers. A thorough understanding of soil mechanics and methodologies as provided within the current Eurocodes should allow for a better design, where a less conservative approach could be taken.

We understand that risk with variable ground conditions is always present and therefore we always emphasise that settlement values are only an estimation of how the ground is likely to behave and move. Therefore, we often incorporate some level of conservatism in design. However, what should not be forgotten is that serviceability limit states verification methodologies such as numerical methods, prescriptive methods, verification through in-situ testing or observational methods are at our disposal to use in order to challenge and potentially reduce the level of conservatism through gathering of better and more representative data, in order to make our design better and more efficient.

Even with the Eurocode Next Generation coming into play with better indication of our approach to serviceability limit state and therefore resulting in a more efficient design, it is still vital that serviceability limit state limiting values are decided based on the design criteria of the structure throughout its design life, using the assessment criteria provided in the current codes. In addition, it is undeniable that further consideration given to methods of assessment of the ground and estimation of settlement can result in a better approach. The latter is most important in dealing with challenges such as variability of ground conditions which often are the reason for which a conservative approach is utilised.

  1. Built Environ (2021), How can UK Housing Projects be Brought in Line With Net-Zero Carbon Emission Targets? L Jankovic et al.
  2. Architects Declare (2019). UK Architects Declare Climate and Biodiversity Emergency [WWW Document]. UK Archit. Declare Clim. Biodivers. Emerg. URL Available at: 5.6.21).
  3. RIBA (2019). RIBA 2030 Climate Challenge [WWW Document]. 2030 Clim. Chall. URL Available at: 5.6.21).
  4. EAC (2021). Energy Efficiency of Existing Homes (No. Fourth). Environment Audit Committee.
  5. BRITISH STANDARDS INSTITUTION. (1995). Eurocode 7. Part 1, General rules (together with United Kingdom national application document). Part 1, General rules (together with United Kingdom national application document). London, British Standards Institution.
  6. N/A (2021), Whole Life Carbon Approved Document Z, N.A
  7. CRC Press (2015), Structural Engineer’s Pocket Book Eurocodes, third Edition, C. Fiona

Article provided by Ronak Amirhosseiny, Senior Geotechnical Engineer at Coffey Geotechnics Ltd


BS8661 Geotextiles: Guidance for specification for basic separation and filtration functions

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Article provided by Ian Fraser, Chair – BSI Committee B553: Geosynthetics. Note: the views expressed above are those of the author and not BSI

BSI has recently published an important new British Standard BS 8661 – Geotextiles: Guidance for specification for basic separation and filtration functions. As the title implies, this document gives designers and specifiers some simple guidance on the selection of a suitable grade of separation and filtration geotextile for their next project. The standard focuses on the lighter and most basic end of the market and recognizes that more stringent design and specification considerations will be required for more onerous applications. The types of geotextiles addressed would generally be utilised, for example, as separation layers under roads, pathways, car parks and other trafficked areas. Although these might be considered the most straightforward applications it is still easy to make simple mistakes that may compromise the integrity of the construction in the future.  Furthermore it should be noted that, by volume, these are easily the most prevalent applications of separation geotextiles and therefore responsible for the greatest share of geotextiles used.

This type of standard has been long overdue in the UK, which has seen a gradual decline in the level and quality of geotextiles used in basic separation and filtration over the last 10 to 20 years.  This decline has taken us to a point where the UK’s standards are lagging behind many other developed countries like the US, Germany, South Africa and the Scandinavian states. The irony is that much of the early development of geotextile manufacture and their application was undertaken in the UK and it could be argued that the use of geotextiles as separation layers was born here.  The decline in standards is mostly due to a fairly poor level of understanding and therefore specification but – before steam starts shooting from your ears – I am not blaming specifiers and designers for that so please read on.

The main practical area of concern expressed by geosynthetics experts is the ability of some materials to withstand installation stresses and continue to function as intended.  I am sure you are reading that last sentence and thinking ‘that’s obvious, of course they must be robust enough to survive installation’. Obvious or not, it is a factor that is all too frequently ignored when specifying and selecting geotextiles in the UK and it is no accident that this is a key issue addressed by most other international separation geotextile classification systems.  The sorts of laboratory tests that we undertake on geotextiles to obtain the important values for parameters that you see on datasheets, like their effective opening size and permeability, for example, are extremely useful for determining a geotextile’s likely performance on site.  However these tests are undertaken on pristine samples in a laboratory, and to be confident that these materials will perform satisfactorily in a real application we must be reassured that the installation stresses will not significantly change their performance.  In simple terms, if the placement and compaction of aggregate over the geotextile is going to tear a hole in the material then clearly the characteristic opening size given on the data sheet will be somewhat academic and its ability to separate is clearly going to be significantly impaired.  Don’t despair because the solution is very simple.  We just need to specify geotextiles that are robust enough, for a range of given conditions, to not be significantly damaged by installation or subsequent application. We can therefore be confident that they will retain their performance characteristics when applied on site.

Whilst the solution is obvious the reality is that specifiers in the UK have not, until now, been provided with a helpful tool to allow them to make an informed choice about the grade of geotextile they need to employ for their given project conditions.  In particular little guidance has been provided on robustness and what we like to call ‘construction or installation survivability’. Without that tool a reasonably detailed level of geosynthetic expertise is required in order to make a choice and being somewhat of a niche area, that expertise is thin on the ground. In reality very few civil engineering undergraduate courses contain much, if any, information on geosynthetics and post graduate geotechnical courses don’t fare much better. To my point above, the lack of guidance and a suitable tool is not the fault of specifiers and designers. Given the current educational environment outlined above it is therefore incumbent upon the geosynthetics industry and its associated experts to help designers by plugging that gap by providing some simple guidance to help them navigate towards the correct decisions. BS 8661 sets out to do just that and provide that tool.

The standard offers a choice of 3 basic grades of geotextile specification profile.  Guidance on the selection of the correct profile for your project is provided based on:

  • subsoil conditions – shear strength/CBR
  • construction conditions – compaction plant/site traffic/fill grain size/layer thickness
  • importance of the filtration function in the proposed application.

As a side note, the functions of separation and filtration often work hand in hand in many UK geotextile applications, mostly because the presence and passage of water is a key part of everyday geotechnical design in this country.  However, there may be instances where filtration is not a concern, for example where you are separating coarse materials or where no significant water passage is anticipated.

The required levels of the parameters quoted in the specification profiles in the standard are defined using current EN test methods (as per CE and UKCA Marking) and include consideration of manufacturing tolerances. These parameters are therefore those which are already tested and quoted by all European and most international manufacturers so are easy to obtain.  As indicated above, designers who are creating a specification for a project can simply run through the selection process and then ask in their specification for a geotextile to comply with, for example, BS8661 Specification Profile 2.  Of course designers can also use the standard to check that a geotextile which has perhaps been offered on a project by a contractor is suitable for the site and construction conditions.

It is encouraging to note that the development of BS8661 has been supported by National Highways, Network Rail and the Environment Agency.

I am sure that designers and other end users will find this to be a valuable tool that they can rely on to help them make more informed decisions and protect the integrity of their works. As with all British Standards, the document will be reviewed regularly so all and any suggestions for improvements will be gratefully received.  BS8661 is available now and if you are a designer I encourage you to obtain a copy and utilise it in your next project. If you are a geotextile manufacturer or supplier I would suggest that you check your product range against the specification profiles to be sure that you comply.


The Development of a Degree Apprenticeship in Geoscience Webinar Summary

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The AGS webinar on The Development of a Degree Apprenticeship took place on 23rd March 2022. 248 people registered to attend the webinar and 90% of attendees would recommend the webinar.

This webinar saw Dr Nick Koor (Reader in Geological Engineering, University of Portsmouth (School of the Environment, Geography and Geoscience)) and Paul Roberts (Regional Director at AECOM) discuss the worrying trend of how the number of students enrolling on Geoscience courses at university has declined over the past six years. The webinar was chaired by AGS Chair, Sally Hudson.

The event also covered the development of a Degree Apprenticeship in Geoscience. This was spearheaded by UGUK at a kick-off meeting in November 2021. A Trailblazer Group for the Degree Apprenticeship in Geoscience has now been formed and is being chaired by Paul Roberts. The group are currently in the occupation proposal stage, with the course is likely to start in 2024.

If you missed this webinar, the replay is now live and available for view on the AGS website for free. Click HERE to view the replay and download the speaker presentations and file handouts.


SiLC Affiliate Scheme Video

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We’ve made it; a 15 minute video to promote the SiLC Affiliate Scheme, which you can watch at We had a very small budget to make this, but individual SiLCs have done a grand job in sending in video clips recorded during the covid pandemic lockdown using their mobile phones and telling us why they get excited about contaminated land, why they came into the profession and why they became a SiLC and NQMS SQP. Watch it and see what they have to say. None of the responses were scripted. Each contributer was sent a short list of questions and whatever they say is in their own words. The contributers also provided the interesting photographs that you will see in the video.

The video is mainly directed at young people, particularly undergraduates or graduates, with the primary purpose of encouraging them to look at the geoenvironmental industry as a career path but also, of course, to join the Affiliate Scheme, become chartered and in due course become a SiLC. However, others who are more advanced in their careers can also join and many have so far done so.

All the contributers to this video show that they are confident in the profession they have chosen and talk with such contagious enthusiasm that ‘who would not want to join them’ in such a rewarding career. They talk with passion about the variety of work that they get involved in, ‘never a dull moment’ as they say, and the variety of disciplines with which they interact. As Ian says, this is an industry with a wide range of specialist skill sets with no one degree or expertise area defining the contaminated land and brownfield sector. Lucy also mentions all the countries around the World that she has worked in as a geoenvironmental specialist as well as across the UK, saying, I travel and get paid for it, so who wouldn’t enjoy that?

Sarah, who is the only one in the video who is not yet a SiLC, but aspires to be one, is really enthusiast about playing her part in the clean up and return to productive use of derelict, contaminated and unsightly sites. Ian, Eleanor and James also talk about maximising the reuse of brownfield sites, making the best use of our overall limited land supply and turning contaminated and derelict sites into beneficial use for communities and at the same time helping to protect our countryside and green spaces against increasing pressure for development.

Danny comments that being a SiLC is a mark of esteem, is part of career development and builds confidence in his own ability. James says that it reflects that you have been assessed by your peers in a thorough and competent manner and you really do deserve to be considered a competent professional. Sarah believes that it helps when dealing with clients as it is a means of demonstrating your credentials and builds confidence that sound advice will be given. Lucy notes that being a SiLC and SQP helps to increase professionalism in our industry by amongst other things being tansparent in identifying the uncertainties in our work and the implications of our conclusions. Improving quality has to be the objective of everyone in our industry and these schemes are part of this process to the benefit of clients, regulators and anyone else with an interest in brownfield regeneration. As indicated by Simon, it is win-win all round.

The SiLC Affiliate Scheme was launched in 2018 and since then both graduates and those more advanced in their careers have joined. They benefit from access to an ‘adviser’ provided by their chosen professional body as they work towards chartership. Once they attain their chartership they have access to a ‘mentor’ provided by SiLC as they work towards SiLC Registration. Some who are already chartered have also joined.

This diagram shows the relationship between the  Affiliate Scheme, the National Brownfield Skills Framework (NBSF, which can be found on the SiLC website and is referred to in the NQMS) and the stages at which the adviser and mentor provide support. An applicant can join the scheme at any stage.

The Advisor provides guidance on gaining chartership with the candidates chosen professional body, the do’s and don’ts and the level of experience required to apply for chartership. They will be familiar with the requirements of their professional body and how this fits into the SiLC programme, but will not necessarily be a SiLC.

The Mentor is a SiLC who is familiar with the level of expertise and experience needed to take the SiLC exam and give advice on how best to fill any gaps. This is an ongoing process with reference to the NBSF, until the candidate is ready to take the SiLC/SQP exam. They can also advise on some of the key aspects that the assessors will be looking for at interview.

This scheme is for those who have a genuine interest in the brownfield land sector, are graduate members (or the equivalent) of one of the qualifying professional bodies, are aiming to become chartered and to join the SiLC Register and have a commitment to the code of conduct of their chosen professional body and that of SiLC.

If this is for you or someone in your team, then visit and find out more.