AGS Magazine March 2022 by AGS Magazine

March 2022

PRESSUREMETERS: THE DEEP DIVE

An introduction to the application and benefits of pressuremeter testing, plus the differences between the different types available

Image credit: Cambridge Insitu Ltd,

DESERT ISLAND GEOTECHNICAL PAPERS

UNDERSTANDING YOUR PEOPLE

CL:AIRE GUIDANCE ON MINE GAS RISK ASSESSMENT

Steve Everton of Jacobs revisits the geotechnical papers that influenced him

The role that workplace inclusion can have on benefitting your business

Good Practice for risk assessment of coal mine gas emissions

ABOUT THE AGS

Chair’s Foreword Welcome to the March issue of the AGS Magazine, in which we welcome in the Spring with a varied collection of articles and updates for your perusal. In this edition we present a thorough introduction to pressuremeter testing for ground investigation by an expert in this field, and we learn about the hazards of mine gas ingress to properties together with the CL:AIRE guidance on assessing and managing this risk. As we filter back to a degree of normality in the workplace, a benefit of lockdown for one AGS member was the opportunity to sift through key geotechnical papers to highlight some key classics, and we learn of those findings in this edition. At the AGS Annual Conference last year many of you heard about building workplace inclusion and in this edition we highlight advice on understanding your workforce in this respect. You may also be interested in hearing about the career path of one of our Geotechnical Working Group members in our regular Q&A feature. It is also time to start our

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programme of seminars and conferences and we encourage you and your colleagues to sign up for these on-line and faceto-face events. Our first free webinar is on 23rd March and focuses on the development of a UK Degree Apprenticeship in Geoscience to address the falling enrolment on university geoscience courses. I hope to ‘see’ many of you there - read on for more details. Remember that several of our on-line seminars are available as recordings via the AGS website for retrospective viewing. We are always on the lookout for additional, informative content for the magazine, so if you have a case study or technical article that you think the wider geotechnical and geoenvironmental public would find beneficial, please do get in touch. We would be interested in your feedback on the magazine and our future plans. Please contact ags@ags.org.uk if you have any comments.

The Association of Geotechnical and Geoenvironmental Specialists (AGS) is a non-profit making trade association established to improve the profile and quality of geotechnical and geoenvironmental engineering. The membership comprises UK organisations and individuals having a common interest in the business of ground investigation, geotechnics, geoenvironmental engineering, engineering geology, geochemistry, hydrogeology, and other related disciplines.

EDITORIAL BOARD Sally Hudson, AGS Chair Caroline Kratz, Forum Court Associates (FCA) Katie Kennedy, FCA Julian Lovell, Equipe Group Calum Spires, Equipe Group David Entwisle, BGS Chris Vincett, Hydrock Lauren Hunt, Arcadis Adam Latimer, Ian Farmer Associates Dimitris Xirouchakis, Structural Soils Emma Anderson, HaskoningDHV UK Jonathan Gammon, Geotechnical Observations EDITORIAL STORY If you have a news story or event which you’d like to tell our editorial team about, please contact the AGS on 020 8658 8212 or ags@ags.org.uk. Please note that articles should act as opinion pieces and not directly advertise a company. The AGS is under no obligation to feature articles or events received. CONTACT US AGS Forum Court, Office 2FF, Saphir House, 5 Jubilee Way, Faversham, Kent, ME13 8GD  ags@ags.org.uk  020 8658 8212  Association of Geotechnical & Geoenvironmental Specialists

Sally Hudson AGS Chair

 @agsgeotech www.ags.org.uk

Inside this month’s issue

FEATURE PAGE 20

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Desert Island Geotechnical Papers

Following the physical return to the office and a conscious move towards digitisation, Steve Everton COVER STORY of Jacob takes a moment to reflect on some of his PAGE 14  “go to” physical geotechnical engineering papers. An introduction to Steve presents a selection of 6 papers, which have pressuremeter testing by been most useful to him over 3 decades plus of experts Cambridge Insitu geotechnical engineering practice. and In Situ SI

UNDERSTANDING YOUR PEOPLE: BUILDING INCLUSION PAGE 24  Helen Townend on the importance of diversity & inclusion.

CL:AIRE GUIDANCE ON MINE GAS RISK ASSESSMENT PAGE 26  Good Practice for risk assessment of coal mine gas emissions.

Q&A: ROB TERRELL PAGE 32  The AGS Magazine conducts a Q & A with Rob Terrell of Ground and Water Ltd.

MORE INSIDE PAGE 5

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News in Short: Incl. upcoming AGS Events

PAGE 8

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Webinar Update: Brownfield Regeneration

PAGE 30

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WAC Testing of Soils Should we bother?

March 2022

H O STE D

E XCLU SI V E LY

The UK geotechnical industry’s premier event. Whether you are a Client looking for assistance with your latest project, a Consultant looking to establish new working relationships, a Contractor in need of a platform to discuss your specialist services, or a Supplier with a new product to promote, Geotechnica is the place to achieve your goals. Build business relationships, introduce new products, stay up-to-date with all of the latest industry developments. Communicate. Promote. Network. Learn.

FREE TO ATTEND 6TH & 7TH JULY 2022 HOSTED BY

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For more information, get in touch via info@geotechnica.co.uk or visit www.geotechnica.co.uk ORGANISED BY

SUPPORTED BY

News in Short AGS Live and Virtual Events 2022 The Development of an Apprenticeship Degree in Geoscience (free webinar) •

Date: Wednesday 23rd March

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Time: 11am (1 hour duration)

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Fee: FOC to attend

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Sponsorship: Headline and Associate packages available

Sustainability in the delivery of Brownfield Regeneration (webinar series) •

Sustainable Remediation Solutions • Date: Tuesday 17th May • Time: 11am (approx. 2 hour duration)

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• Time: 11am (approx. 2 hour duration)

•

Date: June/July TBC

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Fee: FOC to attend

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Sponsorship: Headline and Associate packages available

AGS Annual Conference (live event) •

Date: Wednesday 6th July @ Geotechnica 2022

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Time: 9am – 4pm

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Location: Warwickshire Event Centre, Leamington Spa

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Fee: FOC to attend

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Full details to be released in due course

Ground Risk (webinar) •

Date: September TBC

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Fee: £25 for AGS members or £30 for nonAGS members

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Sponsorship: Headline and Associate packages available

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Full details to be released in due course

Sustainable Management of Soils • Date: Thursday 26th May

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Yellow Book third edition (free webinar)

Fee: £25 for AGS members or £30 for non-AGS members for one webinar. Alternatively, AGS members can attend both webinars for £45 and non-AGS members can attend both webinars for £55. Prices exclude VAT. Sponsorship: Headline and Associate packages available

Data Management Conference (live event) •

Date: Thursday 1st December

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Location: The Burlington Hotel, Birmingham

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Sponsorship: contact the AGS for sponsorship packages

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Full details to be released in due course

March 2022

News in Short Breaking Ground Podcasts: New Episodes Now Live Breaking Ground, a podcast collaboration between Ground Engineering magazine and the Ground Forum, have released two new episodes which are available for free listening: •

Roni Savage, (Managing Director of Jomas Associates) on starting out, growth and leadership within the construction industry

•

Patrick Lane-Nott (Director of Engineering at Hypertunnel) on the history of tunnelling and how Hypertunnel will approach tunneling differently to make it faster

Hosted by Steve Hadley, Breaking Ground covers a wide range of ground engineering related topics. Key themes include sustainability, design, commerce, diversity, health and safety, welfare, construction techniques, education, and industry challenges. Episodes also profile industry members careers within the context of discussing industry issues, construction techniques and case studies. Breaking Ground is available for free download on channels including Spotify, Apple Podcasts and Google Podcasts. To listen to the podcast, click HERE. For further information on the podcast or for podcast sponsorship opportunities please email gforum@ground-forum.org.uk.

The top three AGS publications in the last month 1. Comment on the approach for classifying sites into green, yellow or red 2. AGS Guidance on Waste Classification for Soils - A Practitioners Guide 3. AGS Guide: The Selection of Geotechnical Soil Laboratory Testing To download the publications for free; click here.

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Association of Geotechnical & Geoenvironmental Specialists WHY BECOME AN AGS MEMBER? Enhance your status in the industry. Make a statement about quality and good practice. Participate in the AGS Working Groups and help shape the industry and set the standards.

WHAT DO WE STAND FOR? ■ Good practice in geotechnical and geoenvironmental engineering ■ Quality companies providing a quality service ■ Health and Safety ■ AGS Data Format

WHAT DO WE OFFER? ■ Guidance to good practice ■ Listing in the Directory of Members ■ AGS Magazine focused on ground engineering ‘hot topics’ ■ Legal helpline ■ Chemical safety helpline ■ AGS Loss Prevention Guidance Document ■ Seminars, meetings, conferences and webinars ■ Collaboration with other bodies ■ Liaison with UKAS ■ Lobbying on matters important to the sector ■ Developing and maintaining the AGS Data Format

MEMBERS CAN CONTRIBUTE BY PRODUCING SUCH DOCUMENTS AS: ■ AGS good practice guidance ■ AGS publications ■ AGS safety guidance ■ AGS client guides

MEMBERS CAN PARTICIPATE IN AGS WORKING GROUPS: For further information on the AGS and details on how to become a member visit www.ags.org.uk Established in 1988, the Association of Geotechnical and Geoenvironmental Specialists is a non-profit making trade association which represents over 140 leading companies specialising in site investigation, geotechnics, geoenvironmental engineering, engineering geology, geochemistry, hydrogeology, and other related disciplines.

■ Laboratories ■ Contaminated Land ■ Safety ■ Business Practice ■ Loss Prevention ■ Data Management ■ Executive Committee ■ Geotechnical ■ Instrumentation and Monitoring

AG S W E BI NAR Sustainability in the Delivery of Brownfield Regeneration is a webinar series developed by the AGS Contaminated Land and Laboratories Working Groups. Taking place over two dates (17th May and 26th May), this two-part CPD virtual series will examine some of the more recent policy changes that will increasingly influence how we deliver sustainable brownfield development in the UK. This will include the provision of policy updates, their associated opportunity

• • • •

NEWS & UPCOMING EVENTS and legal perspective on responsibilities and risk. The series will also present awareness of the tools available to assist decision making to sustainable remediation options and waste classification. Each of the two webinars will be two hours in length and will feature three influential and leading UK speakers. These presentations will be followed by an opportunity for audience questions to the expert group.

Date: Tuesday 17th May Time: 11am – 1pm Cost: £25 for AGS members or £30 for non-members. Prices exclude VAT. Register for both webinars for a reduced rate of £40 for AGS members or £45 for nonmembers. Prices exclude VAT

Sustainability in the Delivery of Brownfield Regeneration: Sustainable Remediation Solutions, is the first webinar in this series. In this session we will introduce the Environment Act 2021 and the now mandatory 10% biodiversity net gain (BNG) target for developments in England. We will discuss how it may profoundly alter the economics of site remediation, how developers may leverage opportunities to achieve BNG through development and how to maximise natural capital benefits in remediation. We will then take a tour of some of the tools currently available in the UK to support the decision-making journey and the identification of sustainable remediation solutions.

Presentations The Environment Act – Targets, Consultations and Guidance Claire Petricca-Riding, Partner and National Head of Planning and Environmental Law Irwin Mitchell LLP This seminar will provide you with a guide of the Environment Act 2021 and how it will affect the development sector. We will discuss the targets to be released, the recent consultations and the setup of the Office of Environmental Protection and how all of this fits in with the levelling up strategy. 8

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Image credit: Alan Beattie

BNG and ENG for Remediation Sites Jon Davies, Director at RSK Biocensus / RSK Wilding The remediation of contaminated sites, and the productive reuse of marginal, derelict and vacant land, is often focused solely on built development or a return to agriculture. This is the result of the traditional approaches to valuing land which prioritises built / manufactured capital over natural or social capital. The Global Post-2020 Biodiversity Framework, to be signed by political leaders around the world at COP15 in Kunming, China this year heralds a new approach to dealing with natural resources and sets out a vision for a world living in harmony with nature. As governments around the world seek to make the targets emerging from COP15, and COP26, into a strong, measured and prioritised set of actions, it is clear that we all need to change the way we act, think and measure success. Part of this is the recognition of land as a limited resource and ensuring that our demands on land and the natural environment are sustainable. In this context, we need to be able to understand the best end use of remediated sites, which may not always be built development. In this presentation, Jon will explore Biodiversity Net Gain and Environmental Net Gain and specifically the tools and techniques available for identifying, mapping, quantifying and monetising biodiversity and other natural capital which can help to shape the right outcomes for remediation projects. Green end uses of land, which deliver ecosystem service benefits can be a financially viable alternative, particularly in the light of developing markets for carbon and biodiversity offsets. What tools are now available when considering sustainability? Nicola Harries, Technical Director at CL:AIRE The presentation will introduce the concept of Sustainable Management Practices, showing how companies can start to improve sustainable thinking, decision-making and action across all land contamination activities. In addition you will be provided a whistle stop tour of some of the different tools that are now available to carry out a simple sustainability assessment.

March 2022

• • • •

Date: Thursday 26th May Time: 11am – 1pm Cost: £25 for AGS members or £30 for non-members. Prices exclude VAT. Register for both webinars for a reduced rate of £40 for AGS members or £45 for nonmembers. Prices exclude VAT

Presentations Sustainable Soils Management & the future of Soils Reuse Nicholas Willenbrock, Manager - Definition of Waste: Development Industry Code of Practice at CL:AIRE and Graeme Duggan at DEFRA What is the current state of play and what does industry need to achieve a circular economy of soils? What are the current sustainability goals within current waste regulation and policy frameworks. What changes can we make to waste management to incentivise the sustainable re-use of soil and waste materials? Legal Responsibilities and the Cost of Getting it Wrong Anna Willets (Partner at gunnercooke LLP) and Samantha Riggs (Specialist Environmental and Regulatory Defence Barrister at 25 Bedford Row) This presentation will outline legal responsibilities/liabilities and regulatory guidance relating to: •

Waste definition and classification (including applying Waste Acceptance Criteria – WAC) and the consequences of getting it wrong

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Resources Framework, Definition of Waste Service & self-assessment

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Duty of care and how you can mitigate your risks

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HMRC, Landfill Tax Regimes and associated risks of non-compliance

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Legal barriers to the circular economy and how they can be overcome

Sustainability, Standards and Best Practice Will Fardon (Quality and Projects Director at Eurofins) and Chris Swainston (Principal Environmental Consultant at Soils) We’ll be discussing the role of guidance and formal standards in driving not only best practice and fit for purpose data, but also sustainable solutions in contaminated land investigation. Sponsorship opportunities for this webinar series can be viewed HERE. For further information on the Sustainability in the Delivery of Brownfield Regeneration webinar series please email ags@ags.org.uk

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We’re pleased to announce that we’ll be holding a free webinar on the topic; The Development of a Degree Apprenticeship in Geoscience, on Wednesday 23rd March at 11am. Featuring Dr Nick Koor (Reader in Geological Engineering, University of Portsmouth (School of the Environment, Geography and Geoscience)), and Paul Roberts (Regional Director at AECOM), this event, chaired by Sally Hudson, will examine the worrying trend of how the number of students enrolling on Geoscience courses at university has fallen by 33% (net) since 2015. As part of a multi-action initiative to reverse this trend, University Geoscience UK (UGUK), which represents most Universities who offer Geoscience as a degree, is spearheading the development of a Degree Apprenticeship in Geoscience. Nick will provide an in-depth overview on the trend and Paul Roberts, as Chair of the Trailblazer, will provide an update on progress for the new Level 7 geotechnical engineering course. This webinar will discuss the initiative and discuss how the industry can support the UGUK. Nick is an Engineering Geologist who currently

teaches Geomechanics at the University of Portsmouth to both Undergraduate and Postgraduate students. Prior to being an academic, Nick worked for 22 years on major Civil Engineering and Building Engineering projects in both the UK and Asia. He is the current Chair of the University Geoscience UK committee and is leading the development of a Degree Apprenticeship in Geoscience. Paul is a Regional Director and has been working with AECOM for 35years as an Engineering Geologist delivering Major Infrastructure Projects. Within AECOM his role includes technical support to the Geotechnical teams across the country and liaison with Universities. He sits on the industrial advisory boards of 3 local universities and provides guest lectures sharing his experience with the new generation of ground professionals. Paul has helped universities with establishing Level 6 Civil Engineering courses and represented AECOM on the Trailblazer group for the Level 7 Geotechnical Engineer. Following this theme he is now the Chair of the level 6 Geoscience Trailblazer group. To register for this webinar, please click HERE. The AGS have both Headline and Associate sponsorship packages available for this webinar. Full details are available HERE. To confirm your support, please email ags@ags. org.uk before Friday 4th March.

March 2022

Sustainability in the Delivery of Brownfield Regeneration: Sponsorship Packages Sustainability in the Delivery of Brownfield Regeneration is a 2022 webinar series taking place over two dates: • •

Sustainable Remediation Solutions: 17th May Sustainable Management of Soils: 26th May

Prices to attend the webinars start from £25, and the event will last approximately two hours in length. The AGS have both Headline and Associate sponsorship packages available for these webinars, which result in double the exposure! Our packages offer an affordable way to reach a worldwide audience across the AGS Magazine, our database of over 4500 delegates, our social media channels and of course, during the webinars itself, (which will also be available for purchase on the AGS website post-event).

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ASSOCIATE SPONSOR Price: £550 (members) or £850 (non-members) • • • •

Our current packages for these webinars are detailed below:

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HEADLINE SPONSOR

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*one package available Price: £1000 (members) or £1,300 (nonmembers) • • • • • • • • •

Company website link or pop-up promotion to feature during both live webinars Large logo on sponsor slide during the webinars Company mention during webinar opening and closing addresses Logo and overview in the event program Company Q&A feature in AGS Magazine (5,440 subscribers) Full page advert in AGS Magazine (worth £400) Two complementary event registrations (worth up to £90) Company logo and overview featured on the webinar registration pages Logo featured on promotional marketing 12

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emails Company logo and overview on the AGS’ Twitter page (3,208 followers) Company logo and overview on the AGS’ LinkedIn page (5,730 followers) Company logo featured on replay email campaigns Company inclusion in a follow up article in AGS Magazine (5,440 subscribers)

• • • • •

Logo on sponsor slide during the webinars Logo and overview in the event program Company mention during webinar opening & closing addresses Logo featured in promotional marketing emails Company directory insert in AGS Magazine, worth £50 (5,440 subscribers) One complementary webinar registration (worth up to £30) Company logo and overview on the AGS’ Twitter page (3,208 followers) Company logo and overview on the AGS’ LinkedIn page (5,730 followers) Company mention in a follow up article in AGS Magazine (5,440 subscribers) Company overview on the AGS website Company logo featured on replay email campaigns

All prices exclude VAT. Packages are limited, however bespoke packages can be developed with companies (subject to space) to suit all budgets. If your company would like to sponsor both events in this brownfield series, or if you’d like any further information, please contact Caroline Kratz on ags@ags.org.uk

Since our first webinar in July 2020, our virtual event programme has been a huge success with 5,000+ delegates registering to attend from countries across the globe. We frequently have attendees from USA, Canada, Hong Kong, Australia, Italy and UAE to name but a few, and sponsorship provides a fantastic opportunity to put your company and its initiatives in front of a worldwide audience. The AGS have both Headline and Associate sponsorship packages available for all webinars in 2022. Packages are limited, however bespoke packages can be developed with companies (subject to space) to suit all budgets. Please see package details below:

HEADLINE SPONSOR

ASSOCIATE SPONSOR

*one package available per webinar

*10 packages available per webinar

Price: £800 (members) or £1,100 (nonmembers) • Company website link or pop-up promotion to feature during the live webinar

Price: £350 (members) or £650 (nonmembers)

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Large logo on sponsor slide during the webinar

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Company mention during webinar opening • and closing address

•

Logo and overview in the event program

•

Company Q&A feature in AGS Magazine (5,440 subscribers)

•

Full page advert in AGS Magazine (worth £400)

•

Two complementary event registrations (worth up to £180)

•

Logo on sponsor slide during the webinar

•

Logo and overview in the event program

•

Company mention during webinar opening & closing address Logo featured in promotional marketing emails

•

Company directory insert in AGS Magazine, worth £50 (5,440 subscribers)

•

One complementary webinar registration (worth up to £90)

•

Company logo and overview on the AGS’ Twitter page (3,208 followers)

Company logo and overview featured on the webinar registration page

•

Company logo and overview on the AGS’ LinkedIn page (5,730 followers)

•

Logo featured on promotional marketing emails

•

Company mention in a follow up article in AGS Magazine (5,440 subscribers)

•

Company logo and overview on the AGS’ Twitter page (3,208 followers)

•

Company overview on the AGS website

•

Company logo and overview on the AGS’ LinkedIn page (5,730 followers)

•

Company logo featured on replay email campaigns

•

Company logo featured on replay email campaigns

•

Company inclusion in a follow up article in AGS Magazine (5,440 subscribers)

All prices exclude VAT. If your company would like to support any AGS webinars or if you’d like any further information on the events, please contact Caroline Kratz on ags@ags.org.uk.

March 2022

Figure 1. A self boring pressuremeter, the cutting shoe and internally positioned dragbit are clearly visible. Photo by Cambridge Insitu Ltd, 2022

An Introduction to Pressuremeters Article contributed by Thomas Cragg - Cambridge Insitu Ltd John Holt, Senior Geologist – In Situ Site Investigation Ltd

ressuremeter testing (PMT) is a well established insitu testing technique for ground investigation, referenced in Eurocode 7 (EN 1997-2). The objective of a pressuremeter test is to measure the Insitu deformation of soils and rocks by the measured expansion of a cylindrical pressurised membrane (EN 1997-2). These instruments are employed typically to

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provide insitu strength, stress and stiffness parameters of soils and rocks. This type of testing provides high quality information due to the minimised disturbance of the insitu ground state, particularly when compared to samples removed for geotechnical laboratory testing. Testing is carried out in accordance with the relevant sections of BS EN ISO 22476, depending on the type of pressuremeter deployed. To achieve the desired parameters, all pressuremeter tests consist of an incremental increase and decrease of radial stress, acting on the material at the borehole wall. This

Right: Figure 2. Graph showing the field curve of pressure vs displacement as produced by a digital direct strain measuring pressuremeter. Image by Cambridge Insitu Ltd, 2022

varying radial stress is dictated by the pressure within the instrument itself, which is controlled by an operator at the surface. During testing, the borehole wall is loaded as a cylindrical cavity. The change in pressure and resulting movement of the cavity are recorded. This demonstrates a cavity expansion with an increase in cavity strain, allowing for a closed form analytical solution. It is possible to avoid empiricism, depending on the specific pressuremeter used. The way the instrument’s pressure is controlled by the operator entirely dictates the type and quality of the test, as does the insertion technique. Some of the pressuremeters outlined in this article have the capacity to measure direct pressure and direct displacement, which can be converted into stress and strain. From here, the pressuremeter data can be analysed to produce key engineering parameters for geotechnical design. This procedure requires careful categorisation of the data. Transparent data processing and appropriate analysis is vital to ensure accurate determination of geotechnical parameters. Some of the parameters that can be derived

from pressuremeter data include the following: Insitu horizontal stress Yield stress Limit Pressure Undrained shear strength

σho Pf

Plm Cu

Frictional strength properties ϕcv , ϕpk , C' Initial shear modulus Shear modulus Young’s Modulus

Pressuremeter Types

Gur E

Several types of pressuremeter exist, suiting different applications and ground conditions. However, most pressuremeters have a cylindrical flexible membrane which expands when pressure is applied (like inflating a balloon). During a live test compressed air or oil is applied down an umbilical. This then causes the flexible membrane to expand, causing the borehole wall to deform. In addition to the above description of a typical pressuremeter, is the Flat Dilatometer (DMT) or Machetti Flat Blade Dilatometer, which

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March 2022

Right: Figure 3. A Flat Dilatometer. Photo by Studio Prof. Marchetti S.r.l. operates in a different manor. This consists of a flat metal blade with a flush circular steel membrane on one side. The DMT is driven into the ground using a Cone Penetration Testing (CPT) rig or drilling rig. The metal membrane is then pressurised with compressed gas and expansion measured at specific, given, points through the test period. From here, these instruments can be divided into those that measure a change in volume and pressure, and those that directly measure down-hole pressure and radial displacement.

Ménard Pressuremeters The former are Ménard pressuremeters and have a more “classical” design. They measure a change in fluid volume as opposed to radial displacement, as well as measuring fluid pressure. The sensors for measuring these variables tend to be at surface as opposed to down-hole. Some modern versions of this style of pressuremeter provide a digital output. These instruments provide a different set of data to radial displacement pressuremeters owing to the lack of directly measured displacement data. Hence the “Ménard modulus” is the

Right: Figure 4. Rendered CAD images of some radial displacement pressuremeters. From top to bottom; 95HPD, 95HPD (Short), SBPM, RPM. Photo by Cambridge Insitu Ltd, 2022

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primary output of the analysis.

Radial Displacement Pressuremeters

“

displacement (strain). Transducer resolutions can equal 0.1kPa Pascals and 0.3 microns. The output of these instruments appears as a live data stream There are three on a graph viewed via software. main types of

The latter are radial displacement pressuremeters, sometimes radial displacement There are three main types called “Cambridge pressuremeter. These of radial displacement pressuremeters”. These pressuremeter. These three are all based on are instrumented probes; the same concept [...] as are all based on the same that is to say, down-hole concept as outlined above, they all have capacity measurements are taken as they all have capacity to directly via strain gauge to measure stress and measure stress and strain transducers (sets of either strain during a test. during a test. The below 3 or 6), spaced evenly table explains some of the around the probe. These strain individualities of each. gauges measure the displacement of the membrane continuously during a test. A These instruments can be operated in a variety further transducer measures the internal of materials, from very low strength clay total pressure of the probe during the test. or silt and loose sand to high strength rock. Combined, the transducers provide precise They can also be operated in a wide variety of and reliable data for pressure (stress) and environments, both on land and overwater. 

Feature Max working pressure

High Pressure Dilatometer (HPD)

Reaming Self Boring Pressuremeter (RPM) Pressuremeter (SBPM)

20MPa

10MPa

73-75mm / 95-97mm

47mm

88mm

725mm / 570mm

285mm

535mm

No. of strain arms

Total pressure cells

Pore water pressure cells

Pre-bored

Yes

Self-bored

Yes

Pushed

Yes

Probe diameter Length of expanding section

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Figure 5. High pressure control panel used at surface by the engineer/operator to dictate a radial displacement pressuremeter test. Photo by Cambridge Insitu Ltd, 2022

A common application is in conjunction with a rotary drilling rig, as these have the capability to work with all types of pressuremeter mentioned above. Some probes can also be deployed with a standard piezocone attached from a cone penetration testing platform.

Analysis Process

common “ Aapplication is in

conjunction with a rotary drilling rig, as these have the capability to work with all types of pressuremeter mentioned above.

The process to convert the raw data these instruments produce into the relevant engineering parameters can

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be complex. The quality of the test will dictate the confidence in the parameters that can produced.

To achieve the maximum return from pressuremeter testing, the desired outcomes must be considered from the start. Instrument selection, insertion technique and specific or bespoke testing procedures should be considered to match with the expected geology, it’s expected

Figure 6. A high pressure dilatometer ready for deployment under a rotary drilling rig. Photo by Cambridge Insitu Ltd, 2022

engineering characteristics, and the desired parameters.

“

The actual analytical process is focussed around using directly measured techniques for each parameter. Subsequently, a curve modelling technique is utilised to provide an optimised solution to the desired parameters. This process allows both the directly measured and modelling techniques be considered, introducing data redundancy, and providing high levels of confidence.

The actual analytical process is focussed around using directly measured techniques for each parameter.

Once the appropriate approach to the testing has been decided, the tests must be completed in a way that provides high quality data without missing any key parts of the material response. For instance, a test that does not reach a large enough strain in a material may mean that confidence in observed strength parameters is undermined, even if the insitu stress is the primary focus of the investigation.

March 2022

Desert Island Geotechnical Papers Article contributed by Steve Everton, Jacobs

he process of returning to work offices in mid-2021 following a year and half of working from homes has prompted another (probably 4th time in 32 years) major purge of our company “hard” technical libraries. Over the past 18 months I’ve personally struggled in not having my paper “hard” technical library available to me, and in particular those proven “old” papers that we refer to time and time again. This most recent major purge made me reflect that the digital business world that we work in is not perfectly suited to learning, remembering and using the lessons that our forebears took the effort to write down and disseminate. Of course, some technical papers can be found “digitally” in pdf format somewhere on the internet, some legally accessible, albeit surprisingly costly. However, large hardback volumes of proceedings from e.g. the international conferences of the 1970s and 1980s etc. aren’t so easily accessible online. In parallel I reflected on how I learned much of my own personal “geotechnique” over several

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decades, and I reflected that a lot of it came from sitting on floors in various company, Institution and university libraries in between bookshelves, seeking out and reading papers in Géotechnique, QJEG, Canadian Geotechnical Journal, the numerous ASCE proceedings, Soils & Foundations to name but a few. A positive by-product of that was the list of further references in all those papers, along with the other papers in whichever volume I was looking at, which then took me off on other journey of discovery. Therefore, in the spirit of prompting and promoting the dissemination of lessons learned long ago, this paper is the first in, hopefully, a series of articles on technical papers that experienced geotechnical practitioners rely on and return to over and over. The following is a selection of 6 of my “go to” papers, which have been most useful to me over 3 decades plus of geotechnical engineering practice, mainly in design, along with some notes of why I find them useful or what they mean to me. These are Technical papers, from conferences and proceedings not books, not technical reports. They are the ones that are in the folder immediately to hand

(pre-COVID), and are well worn and have been In concluding, it occurred to me that the stapled and sellotaped together several times. following 6 papers appear to be the source of They have personal annotations over figures widely used design charts and rules of thumb, and highlighter shading of key paragraphs. and I then wondered how this non-digital I have deliberately limited myself to only 6 knowledge and “rules of thumb” will be used papers – it would have been easier to have 12 in “digital” and AI-influenced designs of the or 22 or more ! As a result I haven’t included future. And that reinforced my resolve to start a number of great papers on for example, off this series of papers. railway track and sub-grade engineering from “Fraser & Wardle” (1976) “Numerical India, Japan, and the US which were vital in the analysis of rectangular rafts on layered early 2000s when the UK were designing and foundations” Geotechnique 26 No 4 constructing both light rail systems without pp613 - 630 a modern UK track-bed and subgrade design method Graphs of This, along with my Craig if you are interested, then “Soil Mechanics” 3rd Edition influence factors, research the papers of Gerald textbook is probably the settlement correction Raymond, J T Shahu, and Li & most “re-sellotaped” in factors and bending Selig. my collection. The paper

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moment influence is primarily focussed on I add the caveat I am not factors are simply design charts derived from including any of the Rankine presented for a variety 1970s numerical analyses Lecture papers – they are for the design of uniformly well known, free and online of relative stiffnesses loaded rafts for settlement https://www.britishgeotech. (“Stiffness factor”) and bending moment, org/prizes/rankine-lecture. across various taking into account the It was nice re-reading the geometries of raft. relative stiffness of the list of Rankine lecturers again raft and the ground. whilst preparing this article. Graphs of influence factors, settlement Sutherland’s 1987 lecture on Uplift Resistance correction factors and bending moment was my first during my industrial year when influence factors are simply presented for I was encouraged to attend by my work a variety of relative stiffnesses (“Stiffness colleagues. I regret missing Peter Vaughan’s factor”) across various geometries of in 1994 while working away, but particularly raft. The results are extended to address memorable and useful lectures to me were infinite depth or multi-layered ground, and those by Poulos 1989, Burland 1990, Simpson herein lies one of the “golden nuggets” of 1992, Clayton 2010, Lacasse 2015 and Jardine this paper. The combination of Stiffness 2016. My personal close winner is the still Factor of the raft/soil system and varying unpublished David Hight lecture in 1998. I look soil stiffness with depth allows the user, back at those papers in particular and note, probably after several uses of the method, however, that my preferences might be biased to really get an understanding of the by being lucky to have worked alongside those operating zone of influence beneath a slab, authors at some point in my career, or used and what depth is most important to best their work for my own research. If you haven’t characterise accurately by investigation to read the Rankine Lectures, I encourage you to optimise settlement and bending moment, do so, and those might be interesting ones to and hence slab thickness. This acquired start with.

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March 2022

knowledge is vital to good geotechnical and structural engineering design. The method and learning substantially avoids the need for complex numerical modelling, or at least allows one to challenge the predicted behaviours in numerical models.

figure presenting horizontal and vertical effective stress and K0 during unloading and reloading.

“Burland & Coatsworth”, (with acknowledgement to Burbidge) (1987) “Estimating the settlement James Penman extended this work in the of foundations on sands and early 1990s in his Imperial gravels” Proceedings College MSc thesis using Int. Conference on James Penman axisymmetric FLAC Foundations and extended this work analyses, and this has Tunnels, London, 24–26 in the early 1990s in proved to be useful for e.g. March 1987 Vol 1, P1–6.

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buried reservoir structures at the column/slab interface where moments and shears peak and change direction, and are therefore key elements of design of those structures.

his Imperial College MSc thesis using axisymmetric FLAC analyses, and this has proved to be useful...

“Burland, Simpson & St John” (1979) “Movements around excavations in London Clay”. Proceedings of the Conference “Design Parameters in Geotechnical Engineering” British Geotechnical Society London Vol 1pp 13 – 29 This is a good and comprehensive paper discussing measured ground movements and the factors controlling movements around deep excavations. The paper presents back analyses and provides information on applicable operating ground design parameters, and provides a good summary of the real scale of movements to be anticipated. What is particularly useful is the discussion around K0 and earth pressures. The Initial K0 for embedded wall design can be a highly dominant factor in ground movement predictions, and values determined from, for example, Self Boring Pressuremeters certainly, and to a certain extent from suction measurements on thin wall samples, can be very high. The paper includes a very useful

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Marcus Burbidge’s original MSc thesis and his subsequent paper with Professor Burland was based on a very large number of case records of settlements of foundations. This led to a relatively simple empirical basis for settlement prediction, and one which reflected reality whilst predicting settlements much less than many common approaches. Coatsworth extended this original study with additional case records. It is noted that for the most part, SPTs from the original case records were NOT corrected for overburden pressure, that the dominating depth of influence was <breadth of foundation, and that SPT be averaged only over that zone. A simple Compressibility Index is derived and then used to determine settlements “at the end of construction”. A really interesting and useful aspect of the method is that it also predicts long term (30 year) settlements, with these being larger than the end of construction settlements. Many books tell you that settlements on coarse-grained materials are (substantially) complete at end of construction, yet the empirical results suggest that total settlements at 30 years are 150% for static loads, and 250% for fluctuating loads.

Apart from this really interesting facet, the great advantage of this empirical method is that one doesn’t have to try and work out what value of E’/N is applicable to a foundation load case, noting that the range of E’/N for foundations in coarse soils of varying load intensity is massive ! (see CIRIA R143 Clayton (1995))

do WALLAP / FLAC etc. analyses.

“Black & Lister” (1978)– “The strength of clay fill subgrades : its prediction and relation to road performance” Proceedings of the conference Clay Fills, ICE London pp 37 – 48 This useful paper is a great summary of the relationships between CBR and shear strength for clays - coarse soils are generally far less of an issue because their CBR is much higher, hence it is the low strength and plastic materials that cause us most concern. As UK pavement design standards (e.g. the DMRB etc.) have been updated and superseded several times, it is often difficult to know where the background and science supporting those methods lies.

(Note – you may wonder why I use the Burland & Coatsworth paper rather than the original Burland & Burbidge paper ? Well, for daily design I only need the few graphs and equations, which are summarised neatly on one single page in the B&C version, and hence that’s the one I reach for in my folder of useful papers! But please do go and dig out the original B&B paper in the 1985 ICE Proceedings which has a lot more useful information and Adriano Bica’s background to the method.)

“ PhD at University

“Bica & Clayton” (1992) – “The preliminary design of free embedded cantilever walls in granular soil” Proceedings of the Retaining Walls conference, ICE, Cambridge University, July

of Surrey was on free embedded cantilever walls in granular soils, and this paper to the Retaining Wall conference presents a number of highly useful design charts for depth of embedment and bending moment for embedded cantilever walls...

Adriano Bica’s PhD at University of Surrey was on free embedded cantilever walls in coarse soils, and this paper in the Retaining Wall conference presents a number of highly useful design charts for depth of embedment and bending moment for embedded cantilever walls, based on model wall experiments The experimental values of depth of embedment at failure were normalised and presented in design charts which are excellent and simple tools for very quick preliminary design without having to

“Boscardin & Cording” (1985) – “Building Response to excavation induced settlement” Journal of Geotechnical Engineering, ACSE 115 No1 January

There is a lot more in this excellent paper than just 2 key figures and 1 useful table, but those are what I reach for first. Figure 4 provides a chart of Horizontal Strain vs Angular Distortion and plots zones of differing damage showing the inter-relation and importance of these 2 factors in determining how much settlement is too much. Figure 11 provides useful definitions of various different terminology used, which is helpful when speaking to asset owners and other engineers. Table 2 provides the very widely used Damage Classification by description or by crack width.

March 2022

Understanding your people is essential to building workplace inclusion Article contributed by Helen Townend, Technical Director for Ground Engineering, Amey

uilding inclusion at work starts with understanding your people, who they are and what they need to be successful. Embracing difference, the innovation and ideas it brings, is made possible when you recognise the diversity in your business and understand who you are missing, and what insights do you not fully appreciate. We see the search for diversity across every sector being taken seriously as CEOs realise the business benefits and increased productivity that comes from providing diverse teams with an inclusive place to work. Retail and media understand that to appeal to a global audience they must provide products and programming that appeals at a local level. They will not be successful without diversity at every level of their businesses. Modern organisations recognise that to be leaders in industry, their workforce must represent the society in which they operate. They must leverage diverse skill sets and ideas so that the workplace culture provides a sense of belonging for all.

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It is vital for the Geotechnical sector that we become a more attractive career proposition to a wider range of people, to combat the skills shortage and ensure a resilient future. We must rethink where we look for talent and build an inclusive environment where employees from all backgrounds feel they belong. UK major infrastructure clients are driving the inclusion agenda and looking for diversity in their supply chain at every level. The agenda is backed by central government, with a £300bn annual procurement spend. Government and all public clients have rightly been making the move to make better use of every public pound. As a government supplier, Amey is required to demonstrate progress in social value and inclusion, via support for apprenticeships, demonstrating supply chain diversity, support for SMEs, climate change action, the list goes on. Therefore, suppliers who do not address diversity and inclusion in their business will find it increasingly difficult to work for Tier 1 Government suppliers. This adds weight to the business case for inclusion and the requirement for continuous improvement and investment. Building an inclusive culture provides

psychological safety for your teams, ensuring they feel safe to speak up on safety, innovation and mistakes. Inclusive cultures are concerned about the people, not the output, to achieve better performance.

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Build blended teams - create a mix of life experiences, business acumen and technical knowledge. For your next hire, seek out someone who will bring different views and experiences to challenge the status quo and leverage the ideas those conversations ignite.

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Embrace flexible working practices for all employees - for whatever reason someone may require flexibility, be that facilitating care, personal wellbeing, or learning a new skill. Be flexible in your approach and processes – one size does not fit all

Build a Framework that fits your business: •

Approach as a Business Improvement project - inclusion needs resource investment to succeed

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Listen to your team - understand employee and business needs

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Define your strategy - set out a clear plan with relevant, achievable, impactful targets

Build Awareness across the business: •

Communicate your Framework- any culture changes require employee buy in

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Provide safe spaces - listen to the business and better understand employee lived experience

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Provide training - on the framework, the business case and inclusion awareness

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Use established national campaigns supporting inclusion events that resonate with your employee demographic can be the catalyst to raise awareness and create allies. Embedding psychologically safe working practices into business as usual and enabling equality, diversity and inclusion should be a thread underlying every business decision.

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Promote individual ownership of inclusion - each of us tackling what is in our own sphere of influence to build inclusion across the sector.

Looking to the future. Inclusion is a long game, a constant campaign where you build on achievements. What do we want our businesses to look like in 5, 10, 15 years time? We must work to ensure we have the right people in our talent pool to achieve this. Future generations will not stand for organizations that do not truly care about diversity, inclusion and belonging and will look elsewhere. Inclusion is, therefore, not a nice to have, but a core business criterion that wins work and can differentiate your business from the rest of the pack. Helen Townend is Technical Director for Ground Engineering at Amey. She is currently focusing on all aspects of Inclusion at Amey, where she introduced an Inclusion Ambassador employee network in 2020 to enhance employee engagement with the Business’s Embracing Difference Inclusion Strategy. She facilitates a calendar of Inclusion events throughout the year, supports six business wide Affinity Groups, is Co-Chair of Women at Amey and leads on inclusive design.

Disrupt the Status Quo to provide Inclusive Flexible workspaces. •

Look at recruitment processes - diversify your talent pools

March 2022

CL:AIRE guidance on mine gas risk assessment Article contributed by Steve Wilson, The Environmental Protection Group Ltd and Alex Lee, WSP

containing water pipes (also likely the case at Gorebridge). Once these were sealed the gas ingress stopped and the properties were shown to be safe.

In response to the recommendations in the Scottish Government report, in late 2021 CL:AIRE published its Good Practice for risk assessment of coal mine gas emissions. The guidance draws on the experience of the authors who all have a good understanding of the issues that caused the Gorebridge incident. It provides a pragmatic but robust framework on which to base a mine gas risk assessment. It is important to note that to those undertaking mine gas risk assessments that they should not just go straight to the Decision Support Tool in Figure 13.1 without reading and following the advice in the rest of the guide. In particular, there are other key reference documents that must be read in conjunction with the guide, as explained in Section 7, Useful Information Sources.

More recently one of the authors has been involved in a site in Northumberland, which has very similar circumstances; reports of illness that are symptomatic of exposure to high levels of carbon dioxide. An investigation discovered gas inside the properties. However, in this case, a robust investigation followed that determined the points of gas ingress to the properties. This found that the gas was only entering via open, unsealed ducts

Key take points are:

n 2013 reports of illness among residents in Gorebridge, Scotland led to the discovery that carbon dioxide was entering newlybuilt homes. A total of 22 residents from an overall total of 165 in the affected area were reported to have contacted healthcare services between September 2013 and September 2014. The most common complaints were headaches, dry coughs, dizziness and anxiety. The town is in a former mining area and the development was underlain by old mine workings with shafts present nearby. Subsequent investigations led to the residents being re-located and 64 houses being demolished. Whilst it is arguable whether demolition was appropriate or necessary, a subsequent study by the Scottish Government recommended that consolidated guidance was required for the industry on the investigation and assessment of mine gas risk.

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Mine gas risk assessments and mitigation design should be carried out by ‘competent persons’ as defined in the National Planning Policy Framework (NPPF) in England and equivalents in the devolved governments.

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It is important to understand the different methods of working coal, the effect this has on the likely presence of a mine gas

Sealing pathwa credit -

g the most common migration ay (the open water pipe duct) – - Amy Juden, EPG Limited

hazard being present below a site and the corresponding risk of emissions into buildings. At the very least, CIRIA Report C758D (CIRIA, 2019) is considered to be essential reading for anyone undertaking mine gas risk assessments. •

As with any other ground gas assessment development of a Conceptual Site Model (CSM) to avoid an incomplete mental model of the problem is a vital part where there is a source of mine gas, as well as its use in the interpretation of any gas monitoring data.

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Risk assessment using the gas screening values and the ‘points system’ in BS 8485 on its own is not likely to be appropriate

where there is a risk of mine gas emissions on sites with complex CSMs or where mass advection of soil gas could occur. Detailed quantitative assessment of gas emissions may be necessary. •

Finally, risk assessors should consider the effect of foundation construction and other buried infrastructure on migration pathways and the integrity of any barrier layers. The risk assessment should be revisited once all below ground, foundation and slab designed has been fixed to make sure it is still applicable.

At the site in Northumberland an old, unsealed borehole or grout hole is considered the

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March 2022

Gas monitoring for mine gas – credit Amy Juden, EPG Limited

most likely migration pathway for the gas to and assessment for relevance and credibility. have reached housing. It is vital that after Generic statements are not deemed the ground investigation or gas monitoring appropriate and, although a precautionary is complete that any boreholes, probeholes, approach should be applied to any risk grout holes or wells are decommissioned assessment, this is not an excuse to invent and sealed to prevent them hypothetical or extremely unlikely acting as migration pathways hazards or consequences. The use of plastic for mine gas. Advice on Bias can occur when there the expectations and liners that are left in is a desire to be cautious, requirements of borehole place in grout holes are prudent or conservative decommissioning has been in estimates that may the major concern for provided by The Environment be related to harmful gas migration as they Agency and SEPA. In this consequences. Yet such can can leave a void around also lead to the delivery of respect, the co-ordinates of all holes should be accurately unnecessary and costly the outside that can recorded on the logs. The remedial intervention form a pathway. use of plastic liners that are despite a low probability left in place in grout holes are the risks being present. major concern for gas migration as they can Transparent critical thinking is required in leave a void around the outside that can form a reporting that evidence based. pathway. The CL:AIRE guide can be found here. Potential areas of uncertainty in mine gas risk CL:AIRE will be running training courses assessment and the effects of future changes throughout 2022 on how to apply the advice in climate should now also be considered. A provided in the Guide. These will be delivered mine gas risk assessment should be awarded by the authors of the guide so will you get a similar resource and effort as would a mineral first-hand understanding of the theory and risk assessment. It is important to recognise thoughts underpinning it. that this requires site specific investigation

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Plastic coreboxes are the future – here are 5 reasons why In today’s increasingly eco-conscious world, plastic is often a bad word. It pollutes. It takes an age to degrade. It’s killing our planet. On the contrary, wood is renewable, degradable and doesn’t pollute. In short, plastic is not environmentally-friendly. But what if it was? Now available in both single 1.5m channel and double 1m channel variations, RhinoCorebox is a plastic core transport and storage box made from 100% recycled materials. It is unequivocally the future of soil and rock core storage and is by far the best corebox on the market today. Here are 5 reasons why:

1. Zero waste RhinoCoreboxes are made from 100% recycled polypropylene and remain 100% recyclable at the end of their lifecycle. Zero waste. Nothing to landﬁll.

2. 700% cheaper per use On average, wooden coreboxes get used a maximum of four times before being binned and/or replaced. That’s around £4 per use. RhinoCoreboxes can be used upwards of 50 (yes, FIFTY) times. That’s a miserly £0.50 per use for the 1m boxes. Bargain.

3. Easy to clean Contaminants from samples soak into wood when they get wet. That means you can’t use that box again due to cross-contamination issues. That’s not a problem for plastic RhinoCoreboxes. Just jet-wash them down and they’re ready to go again. Reuse.

4. Safer to use Gone are the days of ﬂimsy, painful string handles tearing hands apart. RhinoCoreboxes are ergonomically designed to make sure they’re comfortable to carry. They are lighter than their wooden counterparts, so they reduce your manual handling risk, and they even interlock when stacking for increased stability. Safe.

5. Core security Samples are the name of the game in ground investigation. Wooden boxes are not designed to house samples in a secure, supported manner. It’s literally a round core in a square box. Not good. RhinoCoreboxes are diﬀerent. They cradle your core and ensure it doesn’t get damaged in transit. Take better care of your core.

ADDED BONUS: Storage and transport In comparison to clunky, ﬂimsy wooden boxes, empty RhinoCoreboxes save you 300% on transport costs and up to 300% in empty storage costs. That means more space in your stores for equipment and gear and massive cost reduction on getting boxes to site. Spacious savings.

RhinoCorebox has been developed by industry experts to tackle the issue of dangerously heavy, cumbersome, inefficient, ineffective and unsustainable wooden corebox useage. They replace something that is outdated, ineffectual and wasteful with something you can use again and again.

In short, RhinoCorebox turns a consumable into an asset.

1M BOXES

£25 + VAT EACH

1.5M BOXES

£27.5 + VAT EACH

WAC Testing of Soils – should we bother? Article contributed by Marian Markham, Land Quality Associate Director, Jacobs and Chris Swainston, Principal Environmental Engineer, Soils Ltd

he appended table provides an extract from the analytical results of a Waste Acceptance Criteria test (WAC) from an anonymised site. Such testing can be expensive and yet the need for such testing continues to remain, at times, misunderstood by both clients and consultants. Indeed, there remains a fundamental degree of confusion as to the purpose of WAC testing, even 15 years after they were first introduced under the UK implementation of the Waste Framework Directive. WAC testing is only used to determine how a waste will behave Lead

Sample ID CL/0000123

To reiterate, WAC testing is inadequate on its own for allowing the disposal of soils. The same material must also be tested for total concentrations, which should be used first to define its hazardous characteristics or classification. Logically, WAC testing should only be considered if the soil is known or very

Antimony

Selenium

Zinc

Chloride

Fluoride

WAC_CALC

mg/kg

0.01

<0.01

0.69

Sample Desc CP01 ES 4 0.5 <0.01

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once it’s buried in a landfill. This is carried out primarily through analysis of leachate derived from that waste during laboratory analysis. It cannot be used to determine whether a waste is hazardous or not. Whether a waste is hazardous is dependent upon the Hazardous Waste Regulations and is established by reference to the Hazardous Waste List of the European Waste Catalogue (EWC) on the basis of the absolute amounts present in a substance.

likely destined for disposal of to a Licensed Landfill. Consequently, in the interests of sustainability, reducing costs, reducing sample jars, laboratory time and equipment, we should not by default schedule WAC testing during a typical ground investigation. Submission of waste soils to a landfill accompanied only with WAC results could also result in refusal to accept. Refusal cannot only offend but can also be very costly and embarrassing.

that a material might have. These properties determine at a fundamental level as to how you must treat it as a material for disposal, handling and storage purposes including the application of the Carriage of Dangerous Goods and Use of Transportable Pressure Equipment Regulations to even get it off-site.

The list of potentially hazardous substances for which you should be analysing should be based on the desk study and The list of the ground investigation To restate the point, WAC findings. Indeed, most of the potentially tests are a secondary layer data required for primary hazardous substances of classification emplaced classification is often already for which you should to ensure that as a waste available from the initial be analysing should material they are suitable for ground investigation without be based on the desk placement and compliance further need nor cost, so within the target landfill you can get twice the value study and the ground without generating a future investigation findings. for your analytical sample leachate problem at the costs. The data you need same receiving landfill. The to characterise a waste test is required only after waste classification may already be in your data to be reported, has defined its hazardous properties and only hopefully, stored in an AGS4 or similar format determines whether the waste is suitable for so you can forward it directly to your waste deposition at an Inert, Stable Non-Reactive contractor for characterisation. If in doubt, or Hazardous Waste landfill. There is nothing during the investigation phase as to what you much else you can do with WAC test results. might actually need to categorise, think ahead so as to ensure that you have enough primary As already noted, the primary classification data for a waste contractor to classify the soil of waste soil as Hazardous or Non-Hazardous at a later point. There is no need to schedule is made using the results of analysis of total expensive WAC tests when often they are concentrations of the hazardous substances not needed nor assume on the occasion of that could be in it, not the amount that landfill disposal that they alone will satisfy the potentially comes out after WAC leachate expectation of the receiving landfill. If in doubt, testing. This requirement for solid analysis ask an expert and think the process through. derives from the Waste Framework Directive (enshrined in UK law) and is the process used If this monologue still leaves you wondering, to define the absolute hazardous properties there is a great video about tea bags here https://www.linkedin.com/feed/update/urn:l Total Dissolved i:activity:6686937368596885504/ Sulphate as Phenol Dissolved Organic SO4 Index The AGS published excellent practical guidance Solids Carbon in 2019 “Waste Classification for Soils – A WAC_CALC WAC_CALC WAC_CALC WAC_CALC Practitioners Guide” https://www.ags.org.uk/ mg/kg mg/kg mg/kg mg/kg item/ags-guidance-on-waste-classificationfor-soils-a-practitioners-guide/ 4681 6535 <0.5 43

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March 2022

Q & A with...

Rob Terrell FGS

currently am.

Job Title: Senior Geotechnical/GeoEnvironmental Engineer

What does a typical day entail?

Whilst devouring some muesli, I refamiliarize myself Ground and Water Ltd to my project spreadsheet and prioritize tasks. Whilst What is your background undertaking the reporting, and how did you end modelling or sample assessing up working within the I prioritise, I also make geotechnical industry? sure to check in with my Following 4 years of University mentees, technicians and site workers, providing guidance study, I embarked in a career when needed. in geotechnical Another part Another part and geoof my day is environmental of my day is guaranteeing engineering guaranteeing client client at Ground satisfaction, whether satisfaction, and Water. In whether that that be from hitting 2016, I started deadlines, providing be from hitting as a field deadlines, technician, project aftercare, providing where I learnt or ensuring project the physical project-specific aftercare, and practical or ensuring requirements are aspects of projectaccounted for. the geospecific engineering requirements industry. One are accounted for. year on, I transitioned to the Company:

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engineering career path, applying and developing my knowledge of soil mechanics and chemistry, before steadily progressing to the senior geotechnical/geoenvironmental engineer I

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Within your career to date, what is your greatest achievement? My greatest achievement to date would be an ongoing and constant one; watching

my mentees and colleagues develop and learn their craft, becoming competent and assured geo-engineers. I really enjoy transferring and sharing knowledge and experience to my colleagues, which is an integral part of my senior role within the company.

What is your favourite part of your job? Being in a small (but swiftly growing) company, there is a real family feel and my colleagues are genuine friends who make the days more enjoyable. I am grateful that they support me not only at work, but outside of work also.

What are the most challenging aspects of your role? The industry is fast paced and can be very demanding at times, which can often take its toll; luckily, I have a good team around me and a proactive mindset which mitigates this stress greatly. Comfort food also helps!

If you could do it all over again, would you choose

the same career path for yourself? And if not, what would you change? I believe it is beneficial to undertake a technical/ site based role so that you fully understand the basics as well as the importance of detail. Then when you are an Engineer, you know what is required during site investigations at the earliest opportunity. Therefore, I am happy with the path I took.

What AGS Working Group(s) are you a member of and what are your current focuses? I am part of the geotechnical working group as an early career member. Within the group, I am part of a sub-committee working

on developing guidance and standards regarding underpinned basement foundations. I am also cowriting an article on how site investigations and sampling can be more sustainable.

sustainable, whether it is small factors like using reusable/ recyclable material, to larger factors like engineering design. A global mindset shift is required to ensure we have a healthy world in which to thrive on.

Why do you feel the AGS is important to the industry? Lastly any advice or words of wisdom that I’ve always believed would you give someone collaboration is key to success, who is either considering and by bringing together this type of job or who specialists from across the are progressing towards UK, we can all learn from chartership? each other and encourage sustainable change within the industry.

What changes would you like to see implemented in the geotechnical industry? I believe that there is great potential for the geotechnical industry to become more

Work hard, but never forget that rest is equally important and a healthy work life balance is essential. A stressed and overworked brain will do nobody any good. All work and no play etc..!

March 2022

Upcoming Events SiLC Annual Forum 2022 The AGS, an institution of Specialist in Land Condition, is pleased to announce that the SiLC Annual Forum is taking place virtually on Tuesday 22nd March between 9:30am - 1:30pm. This half day, virtual event will be hosted by SiLC PTP Chair, Ian Evans (Senior Technical Director at Arcadis Consulting and SiLC PTP Chair), and will feature a stellar line up of expert, industry speakers, each covering a wide array of topics. This year’s event will be divided into two themes: NQMS and Sustainable Remediation & Climate Change, and will feature a panel discussion on the future of the NQMS plus virtual breakout rooms.

Programme Theme 1: NQMS: 5 Years On – Where has it added value? Angela Haslam, Senior Advisor, Land and Contamination Management Team at the Environment Agency Environment Agency reflections on the National Quality Mark Scheme for Land Contamination (NQMS) in England David Kerr, Ireland Brownfield Network and Principal Environmental Consultant at Delta-Simons Environmental Consultants (part of Lucion Group) Demonstrating Competency in Contaminated Land in Ireland Paul Nathanail, GHD Technical Director of Contamination Assessment and Remediation & Chair SiLC Register Ltd International perspectives on competency and accreditation for land contamination reporting

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Panel Discussion: The NQMS Going Forward • • • • •

Seamus Lefroy-Brooks, Principal at LBHGEO and Chair of the NQMS (Panel Chair) Angela Haslam, Senior Advisor, Land and Contamination Management Team at the Environment Agency David Kerr, Ireland Brownfield Network and Principal Environmental Consultant at DeltaSimons Environmental Consultants (part of Lucion Group) Paul Nathanail, GHD Technical Director of Contamination Assessment and Remediation & Chair SiLC Register Ltd Ruth Chippendale, Soil and Groundwater Program Manager at Shell International Petroleum Co Ltd

Virtual breakout discussion: What do we see as the Emerging Challenges over the next 10 years in the Land Contamination Sector?’

Theme 2: Sustainable Remediation and Climate Change Joe Jackson, Managing Director at Jackson Remediation Sustainable Remediation and Climate Change – Real Impacts & Real Opportunities Helen McMillan, Associate Director at RSK and SoBRA Considering climate change in controlled waters risk assessment Claire Dickinson, Director at Geo-Environmental Matters Land Condition, extreme weather events and climate change

Tickets Tickets cost £50 for SiLC Members, £20 for retired SiLC’s, £80 for non-SiLC’s and £40 for Affiliate Scheme members. Prices exclude VAT. Local authority staff, students and job seekers may attend the event free of charge. To register for this event, please email silc@silc.org.uk or visit, https://www.silc.org.uk/events/ annual-forum/ to download a registration form.