Introduction

The use of the Dynamic Cone Penetrometer (DCP) also commonly known in the UK as the TRL Penetrometer or TRL Probe has been under discussion recently in the AGS Safety and Geotechnical Working Groups due to concerns raised by members regarding the significant danger of injury from damage to underground utilities, manual handling injury and the quality of the geotechnical data output.

The Dynamic Cone Penetrometer (DCP) is an instrument designed for the rapid in-situ measurement of the structural properties of existing road pavements constructed of unbound materials. The robust and simple design means that the DCP is quick and easy to use, portable, low cost and suitable for use in locations where access may be difficult. It is commonly used in the UK to determine a California Bearing Ratio (CBR) profile for pavement design.

This article discusses the history of the test, the safety concerns and geotechnical design limitations of the DCP in modern practice and provides alternative methods which must be considered by the Designer.

Historical Background

The earliest technical references to the Dynamic Cone Penetrometer (DCP) suggest that it was developed in 1959 by Professor George F. Sowers, Professor of Civil Engineering, Georgia institute of Technology, Atlanta, USA¹. The original DCP used a 15 lb weight dropping over 20 ins and used a 40^o cone. This DCP was originally developed for field exploration and for verifying individual footing foundations during construction. The DCP was further developed in South Africa for the evaluation of in-situ pavement strength or stiffness of newly constructed roads in the 1960s. Dr. D. J. van Vuuren designed this version of the DCP with a 30° cone².

The Transvaal Roads Department in South Africa began using the DCP to investigate road pavement in 1973³. Kleyn reported the relative results obtained using a 30° cone and a 60° cone. In 1982⁴, Kleyn described another DCP design, which used a 60° cone tip, 8 kg (17.6 lb) hammer, and 575 mm (22.6 in) free fall. This design was then gradually adopted by countries around the globe including the USA and by Transport Research Laboratory (TRL) in the UK. In 2004, the ASTM D6951-03 Standard Test Method for Use of the Dynamic Cone Penetrometer in Shallow Pavement Applications described using a DCP with this latest design⁵.

Typical DCP/TRL Probe

DCP Procedure

The 8 kg free fall hammer is manually lifted and dropped through a height of 575mm. The distance of penetration of the cone tip is then recorded and the cycle repeated. Continuous measurements can be made down to a depth of approximately 850mm or when extension rods are fitted to a maximum recommended depth of 2 metres.

DCP testing consists of using the DCP’s free-falling hammer to strike the cone, causing the cone to penetrate the base or subgrade soil, and then measuring the penetration per blow, also called the penetration rate (PR), in mm/blow. This measurement denotes the stiffness of the tested material, with a smaller PR number indicating a stiffer material. In other words, the PR is a measurement of the penetrability of the subgrade soil.

Technical Output from the DCP

The most common use of the Dynamic Cone Penetrometer (DCP) is to provide a quick and simple field test method for evaluating the in-situ stiffness of base and subgrade layers for roads and highways, and DCP testing has been used in many countries and US States for subgrade evaluation and QA/QC procedures. The greatest advantage offered by the DCP is its ability to penetrate underlying layers and accurately locate zones of weakness within the pavement system.

Correlations have been established between measurements with the DCP and conventional in-situ CBR so that results can be interpreted and compared with CBR specifications for pavement design. TRL Report TRL587⁵ is the most common correlation method used in the UK and is widely specified. A typical test takes only a few minutes and therefore the instrument provides a very efficient method for obtaining information which would normally require the digging of test pits.

Technical Limitations

This instrument is typically used to assess material properties down to a depth of 1000 mm below the surface. The penetration depth can be increased using drive rod extensions. However, if drive rod extensions are used, care should be taken when using correlations to estimate other parameters, since these correlations are only appropriate for specific DCP configurations. The mass and inertia of the device will change and skin friction along drive rod extensions will occur.

Correlations to CBR in homogenous, fine grained soil types are potentially the best use of the tool, or for finding boundaries of known (engineered or natural) layers where there is significant difference in resistance i.e. soft clay over dense gravel. Heterogenous soil types, e.g. Made Ground, with a recommended CBR from DCP may represent a false materials characterisation presented in a report to a civils designer not fully understanding the technique’s limitations.

Health and Safety Concerns

The nature of the test means it is manually operated from ground level without view of the materials and ground conditions being penetrated. The standard equipment comprises in basic terms a metal cone which is connected to metal rods which are driven into the ground using a metal weight and slide mechanism. Incidences of personal injury from manually driving or pushing metal spikes or road pins into buried services have been well documented and must be considered a significant risk. The equipment is not insulated and the procedure requires the operative to hold the equipment^6,7 and includes the potential to force-drive through obstructions which might include unobserved buried services.

Although not a DCP test but effectively a similar process, AGS in 2017 (SP Energy Networks) reported an incident where an operative drove a steel road pin into a HV electrical cable and more recently a Safety Alert was released by Geoffrey Osborne in 2019 relating to a similar incident. Driving of road pins on Network Rail requires a permit as it is deemed a significant risk and many contractors have banned the use of road pins or the driving of other metal rods (i.e. earth spikes) into the ground.

With regard to manual handling, the equipment is bulky and unstable unless held firmly at what may be head height for some operators including the 8 kg hammer at the top. Generally, it requires two persons to perform the operation, but is often carried out by single operators to minimise cost. Although some DCP systems have mechanical jacks to extract the rods the typical use in the UK is by back hammering or manual pulling if there is resistance during extraction of the rods and cone. These practices could lead to not only damage of the equipment but the risk of musculoskeletal injuries must be considered.

The device was designed before modern standards in health protection, or the practicality of manual handling in a more regulated industry was considered. It is the role of the Designer in CDM to reduce or preferably eliminate risks. Designers specifying a DCP as part of a compliant ground investigation to obtain data for pavement design are simply failing in their CDM duty where this hazard is identified because a CBR value can be obtained in a safer way which can reduce or even eliminate the risk.

Alternative methods for CBR

The common practice to determine CBR values before DCPs were through collecting a bulk sample from hand excavated pits and carrying out laboratory testing. It is acknowledged that excavating a trial pit to obtain a sample is not without risk, but that is a recognised industry methodology and would be expected to have mitigation to avoid underground services strikes.

In situ CBR values can be obtained from surface or the base of a hand excavated trial pit using In-situ CBR equipment or Plate Load Test (PLT) equipment in accordance with BS 1377 procedures. The limitation of these tests is that they only provide a single value and not a profile and results can be detrimentally affected by coarse materials in mixed soils or near surface desiccation in fine soils.

If a CBR by depth profile is essential for design then the use of equipment such as the Lightweight Deflectometer (LWD) could be considered. The LWD is a device that estimates the in-situ modulus of a material using the impulse load produced by the impact of a falling weight. LWDs are particularly useful for estimating the moduli of asphalt, aggregate base, granular subbase and subgrade pavement layers. LWDs consist of a mass (often 10 kg), an accelerometer or geophone, and a data collection unit and are designed to be light enough to be moved and operated by one person.

Conclusions

The use of DCP to provide QA/QC data for newly constructed highways and earthworks where the location of buried services is known is considered to be a useful, quick, low cost and relatively low risk method. However, when DCPs are specified along routes for new highways or more generally to determine CBR values for pavement design the risk becomes significantly greater from injury through damage to buried services and the method has technical and quality concerns.

The method has been extended for purposes beyond its original design which often do not take into account the modern environment. The construction CBR value provided through laboratory testing which also provides soil type and compacted density, or through an in-situ surface test such as In-situ CBR/PLT is recommended as being faithful to the original correlation with Californian rock gravel performance under relevant loading conditions.

The use of LWD equipment could reduce both the risk of injury from damage to buried services and manual handling even further and this method will provide a CBR depth profile which is now the most common reason in ground investigations for specifying a DCP.

The justification for the Designer to specify DCP must be carefully considered and not driven by lowest cost and a robust risk assessment must be carried out. Ground investigations, especially those on brownfield sites, using the DCP may not be considering the technical limitations of the test and may not fully take into account the safety risks. Therefore, Designers under CDM may be failing in their duty to eliminate or reduce risk and through specifying DCPs are putting persons at harm.

The AGS is currently considering the safe use of DCPs and alternative methods in order to reduce or eliminate the safety risks to members. It would welcome opinions and thoughts from its members and also technical data which could support the promotion of alternative methods.

References

¹ George F. Sowers and Charles S. Hedges: 1966 : Dynamic Cone for Shallow In-Situ Penetration Testing – Vane Shear and Cone Penetration Resistance Testing of In-Situ Soils, ASTM STP 399, Am. Soc. Testing Mats., p. 29.

² van Vuuren, D. J. : 1969 : Rapid Determination of CBR with the Portable Dynamic Cone Penetrometer, The Rhodesian Engineer.

³ Kleyn, E. G. : 1975 : The Use of the Dynamic Cone Penetrometer (DCP). Transvaal Roads Department, South Africa.

⁴ Kleyn, E. G., Maree, J. H., and Savage, P. F. : 1982 : The Application of a Portable Pavement Dynamic Cone Penetrometer to Determine in situ Bearing Properties of Road Pavement Layers and Subgrades in South Africa. The European Symposium on Penetration Testing, Amsterdam, Netherlands.

⁵ ASTM D6951 / D6951M – 18 : 2018 : Standard Test Method for Use of the Dynamic Cone Penetrometer in Shallow Pavement Applications.

⁶ Zohrabi, M and Scott, P.L : 2003 : TRL Report TRL587, The correlation between the CBR value and penetrability of pavement construction material. Transport Research Laboratory

⁷ Done, S.; Samuel, P. : 2004 :User manual UK DCP 2.2. Measurement of road pavement strength by Dynamic Cone Penetrometer.

⁸ Jones C R and J Rolt (1991). Operating instructions for the TRL dynamic cone penetrometer (2nd edition). Information Note. Crowthorne: Transport Research Laboratory.

⁹ BS 1377 : 1990 : Methods of test for soils for civil engineering purposes. British Standards Institute

Article contributed by James Harrison, previously Delta Simons and Julian Lovell, Equipe Group

NHBC is the UK’s leading warranty provider for new homes in the UK with a market share of around 80%. We deal with over 4,000 sites per year from 9,000 house builders on our Register with around 165,000 new homes currently registered annually.

 

Builders on the NHBC Register are required to build new homes in accordance with NHBC’s Standards to be acceptable for Buildmark warranty cover. The Standards specify the Technical Requirements of NHBC along with the performance standards to be achieved in the design and construction of new homes. Guidance is also provided on how the performance standards may be met.

Part 4 of the NHBC Standards covers foundations including requirements for; land quality, building near trees, strip and trench fill foundations, raft, pile, pier and beam foundations, and vibratory ground improvement techniques.

Consultants and/or specialist contractors preparing remediation strategies or substructure designs for NHBC registered house builders should be aware of the requirements of NHBC’s Standards. This is to ensure that the designs prepared will satisfy NHBC’s Technical Requirements and performance standards in order to be acceptable for Buildmark warranty cover.

Additionally landowners, land developers, development agencies and third parties remediating brownfield land for sale to house builders for residential development should also be aware of NHBC’s Standards and requirements. This will help house builders to avoid potential difficulties when they register the site for Buildmark warranty if the remediation strategy adopted, and the verification of any works undertaken, prior to acquisition of the land does not satisfy NHBC’s requirements. NHBC can offer support to non-NHBC registered companies remediating land for subsequent sale for residential development through a Land Quality Endorsement (LQE) service (www.nhbc.co.uk/lqe)

 

The NHBC Standards are available online at:

http://www.nhbc.co.uk/Builders/ProductsandServices/Standardsplus2019/#7

In Part 4 of the NHBC Standards, Chapter 4.1: Land Quality – managing ground conditions provides a framework for managing geotechnical and contamination risks with the objective of ensuring that:

• All sites are properly assessed and investigated for potential geotechnical and contamination hazards.
• Foundations and substructure designs are suitable for the ground conditions.
• Sites are properly remediated where necessary or appropriate, and design precautions are taken.
• Appropriate documentation and verification are provided to NHBC.

On potentially hazardous sites, NHBC seeks to adopt a pro-active risk management regime on developments registered for Buildmark warranty with the aims of:

• Reducing the potential for defective or damaged buildings.
• Ensuring risks to human health are addressed.
• Mitigating the likelihood of claims against Buildmark and significant claims costs for both house builders and NHBC.
• Avoiding reputational damage for all stakeholders.

With the increased use of brownfield and marginal land for residential development, sites frequently have significant geotechnical and environmental issues that need to be satisfactorily addressed in order to meet the requirements of NHBC.

It is essential that a holistic approach to the overall remediation strategy is adopted for all brownfield and marginal sites. This is to ensure that both the geotechnical and environmental issues are considered in tandem and are aligned, so that the aims and objectives of each individual strategy are not unduly compromised, and the overall strategy delivers the desired performance over the 60-year design life required for new homes.

When undertaking technical assessments for new residential developments on brownfield or marginal sites with complex geotechnical and environmental issues, typical areas of concern and focus on proposals and designs submitted to NHBC for Buildmark warranty cover include:

a) Geotechnical

• Inadequate or insufficient geotechnical site investigation and testing.
• The presence of soft and compressible alluvial soils prone to large and potentially long-term settlements.
• Deep un-engineered or partially engineered fills within landfills and quarries.
• Landforming on sites with deep Made Ground or compressible soils with significant cut and/or upfilling resulting in heave or significant settlements.
• Clarity of objectives for geotechnical remediation strategy including proposed foundation solutions.
• The appropriateness of proposed ground treatment(s) to achieve the required bearing capacity and settlement characteristics for the development platform.
• Suitability of engineered fill specifications particularly when proposed for the direct support of spread foundations, including; compaction method, testing regime, testing frequency, treatment of failures and verification.
• The potential for collapse compression/inundation settlement on deep fill sites due to rising groundwater or infiltration including consideration of building drainage solutions on the site.
• The robustness of the verification reporting on the implementation of the earthworks strategy.
• Planned development over, or in close proximity, to high walls.
• Long term settlements secondary and/or creep settlements over the 60-year design life of the new homes. Typically, NHBC will require any assessment to demonstrate that angular distortions/tilts will be no worse than 1 in 400 over the design life.
• Potential short and long-term differential movements between rigid foundations solutions (e.g. piles) and external areas over the design life of the new homes.
• Robust analysis and assessment of short and long-term settlements due to; building loads, raised ground levels, consolidation of cohesive soils and long-term creep in deep backfills and/or Made Ground. This includes the adoption of appropriate geotechnical parameters in settlement analyses/estimates.
• Theoretical settlement estimates/assessments validated by load testing and/or settlement monitoring to demonstrate the actual load/settlement characteristics of the remediated development platform.
• Due allowance for negative skin friction in pile designs on sites with deep fills and Made Ground or significant upfilling.
• Co-ordination of geotechnical and environmental remediation strategies.
• Co-ordination of post-remediation infrastructure/development works to ensure the geotechnical remediation works undertaken are not compromised or adversely affected (e.g. further changes to ground levels after remediation)

b) Environmental concerns

• The adequacy of desk studies/Phase 1 assessments.
• Robustness and completeness of conceptual site models.
• Inadequate or insufficient geo-environmental ground investigation, testing and assessment following Phase 1 investigations.
• The appropriateness of the contaminant testing suite and the frequency of testing and distribution on the site.
• The use of appropriate assessment criteria for contaminants in soils and controlled waters.
• The interpretation and assessment of environmental data obtained from ground investigations and appropriate updating of the conceptual site model.
• Appropriate characterisation of ground gas regimes and any protection measures that may need to be adopted.
• The robustness of the verification reporting following implementation of the environmental remediation strategy.
• Co-ordination of geotechnical and environmental remediation strategies.
• Co-ordination of post-remediation infrastructure/development works to ensure the geo-environmental remediation works undertaken are not compromised.

Often when things go wrong, the investigation of claims against Buildmark identify how these could have been avoided as the following examples demonstrate:

Example 1 – Excessive ground movement

In this example, the new homes were constructed on a site with soft compressible soils, including peat, to depths of 9m below the original ground levels. The properties were on piled foundations with a cantilevered path around the perimeter of the building to support services and safeguard the threshold at entrances to the buildings. However, during development, a piling mat was installed, and ground levels were also subsequently increased by up to 1m to suit final development levels. No measures were implemented to mitigate settlement of the underlying soft ground due to the increase in ground levels. After 12 months, 200mm to 300mm of settlement was recorded around the properties resulting in excessive differential movement occurring between the rigid piled substructure and the external ground. This incurred significant remedial costs on the affected properties. Claims on these properties could have been avoided by ensuring that the strategy for the site not only considered the foundation solution for the buildings but also the effects of raising ground levels on the underlying soft compressible soils.

Example 2 – Excessive ground movement

This example is another situation where potential for post development ground movements was not considered. In this case, the site was underlain by soft and very soft alluvial clays to depths of 15m. Piled substructures were adopted due to the poor ground conditions, but no consideration was given to post development settlements that may occur. A piling mat was provided to facilitate the piling works and some upfilling of the site was undertaken. This resulted in consolidation of the soft alluvial soils with between 75mm to 100mm of differential movement between the substructure and external that compromised access to the building and incoming services. Once again, claims on these properties could have been avoided by ensuring that the strategy for the site not only considered the foundation solution for the buildings but also the effects of raising ground levels on the underlying soft compressible soils.

Example 3 – Contamination in soils

On this rural development of 5 plots with extremely large rear gardens, fibrous boarding was identified in the gardens following occupation by the homeowners. Subsequent investigations revealed the presence of Asbestos Containing Material (ACM) in the topsoil and subsoil, typically within 500mm of ground level but locally up to 1m in depth. The volume and concentration of ACM in the soil was determined to represent a significant risk to human health and substantial remediation was required in the gardens. Investigations identified; inadequate site investigations were undertaken prior to development along with lax control during the decommissioning and demolition of buildings previously occupying the site. The claims on these properties could have been avoided with an adequate site investigation and conceptual site model for the site, together with appropriate controls during the demolition of the original buildings.

In the examples given above, the claims against Buildmark warranty resulted in significant claims costs and disruption to the lives of the affected homeowners. These could have been avoided had the ground conditions been fully appreciated and appropriately managed, during both the development of the scheme design and subsequent construction.

In summary, it is essential that all brownfield and marginal sites with complex ground conditions are appropriately investigated and assessed to identify the potential geotechnical and environmental risks. This should include consideration of; the works required to create the development platform and any additional risk this may create, the types of building proposed and the intended foundation solutions etc.

For residential sites registered for NHBC Buildmark warranty, development designs and proposals will be assessed against the requirements of NHBC’s Standards and expected to satisfy Chapter 4.1: Land Quality – managing ground conditions.  All designers providing services to NHBC registered house builders and/or land owners or land  developers remediating brownfield sites for residential end-use should ensure they are familiar with NHBC’s requirements to; avoid development proposals being determined as unsuitable for Buildmark warranty cover, to assist in reducing risks and to help prevent claims for the benefit of all stakeholders, particularly home owners.

If you’d like to learn more about our LQE service please visit www.nhbc.co.uk/lqe or contact us on lqe@nhbc.co.uk

Article contributed by Adam Gombocz, Senior Geotechnical Engineer and John Jones, NHBC Engineering Manager

 

 

 

 

 

Full Name: Jonathan Adam Latimer

Job Title: Operations Director

Company: Ian Farmer Associates (1998) Limited

Adam is an Operations Director with over 25 years of professional experience working in the ground investigation sector. Adam has worked on a wide variety of investigations, including land development, contaminated land, infrastructure (both road and rail) and utilities projects. Adam holds an undergraduate degree in Geology and holds a vocational qualification in NEBOSH National Certificate in Construction Health and Safety. Adam is also a Freeman of the City of London and is a committee member for both the AGS and BGA.

What or who inspired you to join the geotechnical industry?

There isn’t any one person who inspired me to join the industry, however I have always had a keen interest in Geology from a young age, growing up in the North Pennines with its rich Geology and Mining History. When I left Durham University in 1993, I had already rejected the opportunities of working in the mining and exploration sector (working in politically unstable parts of the world wasn’t really an appealing prospect). I studied a traditional Geology degree and the Geotechnical Industry wasn’t an industry I as was particularly familiar with or aware of. Many undergraduates from Durham would ultimately become involved in the oil and gas sector, law or accountancy. On leaving University I cast a wide net, applying to a wide variety of businesses so I suppose I stumbled into the industry partly by accident.

What does a typical day entail?

I don’t have a typical day and as such it can be quite varied. Like everyone else involved in this industry, the days can be long. As I have progressed up the managerial ladder my role has become more of a support function for the business. With multiple offices and the business now being part of the RSK Group, I have found my time split between all sections of the company. Typically, I will spend most of my time in business development, forecasting, budgeting, estimating, training, auditing and reviewing and developing new documentation. Sadly, my time visiting sites and undertaking reporting and technical reviews has reduced with more managerial duties being the norm.

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

I have been involved in a number of large scale and challenging ground investigations during my time in the industry and I can’t really focus on any one project over another. I am very passionate about the ground investigation industry and the most rewarding part of my job is helping to inspire the next generation of ground engineers, whether this is through the work within the AGS and BGA or through mentoring and training within Ian Farmer Associates.

What are the most challenging aspects of your role?

My role within the business has developed over the past few years and has become more focussed on the business development side and as such a huge challenge is adapting to volatile market conditions. Our industry suffers historically from significant peaks and troughs and you need to react quickly during buoyant times and when there is a downturn. The industry as a whole has also suffered from an acute shortage of experienced engineers and this coupled with a reduction in graduates entering the industry has put enormous pressures on existing staff to meet ever demanding timescales.

What AGS Working Group(s) are you a Member of and what are your current focuses?

I am currently the lead for the Safety Working Group and a member of the Executive Committee. Currently we are working on delivering the inaugural safety conference (Safety in Mind) on the 21^st November at the National Motorcycle Museum. We have secured an excellent line up of speakers and some thought-provoking presentations which I am sure will make it a success. As a group we are continuing to gather feedback from our members on trial pitting and whether it remains a safe and effective method in a changing geotechnical world. We are also at the early stages of a working group on avoidance of buried services with collaboration with the BDA and FPS.

What do you enjoy most about being an AGS Member?

The AGS provides a unique opportunity for like-minded people to discuss issues within the industry in an honest and frank way. The AGS membership is an essential vehicle to share good practices in an open forum for the greater good of the industry.

What do you find beneficial about being an AGS Member?

Being a member of the AGS provides members with an unrivalled opportunity to have a voice in how the Geotechnical Industry should operate. Fantastic work has been done by the members of the AGS to shape the future of the industry and that is credit to the diligence and tireless work of all the professionals we are fortunate to have working in the sector. There is a wealth of publications, position papers and articles which provides invaluable information and all this is available for the benefit of the members on the website or through the conferences held annually.  

Why do you feel the AGS is important to the industry?

The AGS offers a unique opportunity for like-minded professionals who are passionate about the industry to work collaboratively for a common goal to improve the image of the Geotechnical sector. The AGS is the only trade association which includes a mixture of contractors, consultants and clients which offers a wealth of knowledge and experience to help shape a strong and stable future and only with us working together can we make a tangible difference.

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

The Geotechnical Industry has seen significant strides in technology and health and safety since I joined in the mid-90s. There is of course lots of work to do and as an industry we can’t stand-still and need to continue to evolve. The recent survey between the AGS and BDA on the state of the industry offered some food for thought for all of us working in ground investigation and although the results may not have been a big shock, there is still much work to do in order to improve the image of the industry, not just within our membership but also throughout the wider construction sector.

Full Name: Zita Mansi
Job Title: Senior Associate
Company: Beale & Co

Zita has specialised in environmental and construction professional indemnity law since May 2002.  Her construction practice includes the defence of claims against engineers, architects and other construction consultants and bringing claims for contribution and counterclaims for fees where necessary.

Her environmental practice includes: defence of claims against construction consultants arising out of contaminated land issues; defending claims in negligence, public or private nuisance for losses attributable to environmental factors (contamination, odours, noise, vibration, dust, flooding etc); responding to enforcement actions and investigations undertaken by various regulators following environmental incidents (including advising before and during interviews under caution, submissions to the regulator regarding level of harm caused, and establishing whether the regulator has followed its own internal policies and procedures); defending environmental prosecutions and related third party claims.

Zita is responsible for the day-to-day conduct of litigated and non-litigated disputes and frequently acts in multi-party disputes in the TCC, in mediations and other forms of ADR. She also acts in regulatory matters in a construction context, advising clients in response to HSE investigations and defending prosecutions.

What or who inspired you to become a lawyer in the construction industry?
During my training contract to become a solicitor I did a seat in the construction team of the firm I was with. I really enjoyed the complexity of construction projects and every case is so different and offers a new challenge. There are also many technical as well as legal issues to understand too. From early on I was involved in defending claims brought by developers against ground engineers. I developed a special interest in these types of claims and helping engineers to put in place simple measures to avoid them.

What does a typical day entail?
Every day is different of course but a typical day would involve reviewing documents, attending meetings and / or phone calls with clients. Dealing with ad hoc queries. We also manage the AGS Legal Helpline so I quite often will deal with calls from that.

Are there any cases which you’re particularly proud to have advised on?
I often defend prosecutions brought by the Environment Agency and on many occasions we have persuaded the Agency not to prosecute our client which is extremely satisfying.

What are the most challenging aspects of your role?
I will often have multiple deadlines running at the same time so managing these, my time and multi-tasking between them can be difficult. It can also be difficult to switch off when I’m not in the office from certain cases that are particularly challenging.

What AGS Working Group are you a Member of and what are your current focuses?
I am a member of the Loss Prevention Working Group, which focusses on commercial risks faced by members and how to reduce them. One of our objectives is to get across the message that there are simple things members can do to reduce their exposure to claims. The group held a seminar in London recently on ‘Commercial Risks’ which I was lucky enough to speak at, covering collateral warranties, reliance and limiting liability. We are hoping to re-run the seminar in Manchester later in January 2020.

What do you most enjoy about being an AGS affiliate and why is it beneficial?
Being involved in the AGS gives members a great opportunity to share their knowledge and hear from other members and learn from them. I find this incredibly beneficial in my role as a lawyer and also on the Loss Prevention Working group. Understanding the reality of what the members work involves and the practical issues they face means that as a lawyer I can make my advice more relevant.

Why do you feel the AGS is important to the industry?
The AGS is an important focal point and repository for know-how tailored to this particular industry. It helps to maintain standards and their work can influence other industry bodies.

What changes would you like to see implemented in the geotechnical industry?
I would like to see an acceptance by employers and clients that it is reasonable for engineers and contractors to limit their liability. Unlimited liability benefits no-one and only puts the consultant / contractor at risk of insolvency.