Evaluating carbon emissions and carbon efficiency of ground investigation projects

Ground investigation is pivotal to the construction of geotechnical structures, to keep structures safe, the ground needs to be understood. However, the ground is often the least understood component of construction, despite harbouring the largest technical and financial risk. In addition, the emergence and acceptance of the climate crisis has placed additional constraints on ground investigation that add to these technical and financial risks. The objective of this project is to evaluate and quantify these additional factors, and their potential impacts on the overall geotechnical scheme.

The associated direct carbon emissions from ground investigation arise from the transportation and organisation of services and materials to the site, works directly at the site, and the realisation of site project goals. However, the most carbon-intensive aspects of ground investigation are the combustion of diesel and the use of concrete. Most emissions associated with concrete are off-site and come in the form of embodied carbon, whereas diesel is used both for the welfare buildings on site and for the operation of site equipment, 1 litre of diesel emitting around 2,690g of CO2.

Image of Cable Pedrcussion Drilling Rig
Typical usage of a cable percussion drilling rig including the diesl engine housed in the red box.

Soil Engineering, the project partner, is undertaking an in depth review of the use of fossil fuels in their business as they aim to reduce carbon emissions by 40% in 8 years. The business has an inherent reliance on plant usage making this an operational as well as behavioural challenge. To address this, Soil Engineering have instituted a new data collection system to record and allow analysis of fuel use. While the dataset is in its relative infancy, the scale of works Soil Engineering is involved in means it grows rapidly every day. In parallel, a major productivity review is underway, which allows the interrogating of plant outputs in greater detail than ever, permitting a combined analysis of fuel usage and equipment efficiencies in different lithologies and environmental conditions.

The aim of this project will be to analyse the combined dataset of fuel use and generated outputs, identify typical carbon emissions associated with different investigation activities, and investigate modifications and strategies to reduce the carbon emissions of these activities. There is also scope to widen the remit and to pair this work with the wider UK Soletanche Bachy group, within which Soil Engineering sits. This would allow an understanding of the impact of greater investment in ground investigation on the full life cycle of ground improvement and piling schemes, from an environmental rather than financial cost basis, which is a key business driver.

Additional support for this project would come from Soil Engineering’s Leeds office (SEGL), and may benefit from the input of Roger Bullivant’s North West office. The candidate would be required to spend some time working with these partners as part of the PhD project. Data will be provided from SEGL’s in-house dataset following a partnered review between SEGL and the candidate.

The first stage of the project will involve an interrogation of the available fuel use data to define a dataset that can be analysed with confidence. Once a suitable dataset has been identified, the project(s) will be anonymised to support any necessary or opportunistic publication arising out of the study.  The current existing master dataset includes some 100+ projects of varying scope and scale and it grows daily, which will allow a broad selection to be made.

The second stage of the project will use the identified datasets to build a series of conceptual models that will allow a consistent comparison of the carbon efficiency of ground investigation techniques removing the influence of ancillary fuel use, such and heating and lighting, which will be evaluated separately to assess the influence of seasonality on fuel use.

Arrow showing CO2 being driven down
This project will look to reduce Carbon Dioxide emissions in the ground investigation industry

The final stage of the project will see the created data sets and models incorporated into Soil Engineering business practices, supporting a transition to and adaptation of low carbon initiatives and deployment of new workflows.

We would anticipate that the study will identify not only key technical benefits and environmental impacts but also provide SEGL with external feedback on the effectiveness of the data collection. SEGL will develop a wider understanding of the impact of ground investigation on site selection foundation design, site selection and the resultant potential positive environmental impacts of iterative design in both foundations and ground investigation practice.