Conventional ground improvement techniques are highly invasive, frequently energy intensive and may require the introduction of environmentally damaging chemicals or carbon-intensive materials into the subsurface (e.g. chemical grouts, cement). The construction sector is responsible for 7% of carbon emissions in the UK. The UK target for 80% reduction in carbon emissions by 2050 (against the 1990 baseline) presents both challenges and tremendous opportunities for the UK construction sector in the transition towards a low-carbon economy. The use of cementitious materials is pervasive in conventional ground improvement techniques, and with cement production contributing 5-7% of total global CO2 emissions there is a clear need for the development of new ground improvement technologies.

Over the last ten years the geotechnical engineering research community has witnessed the creation of a new subdiscipline: biogeotechnics a multi-disciplinary field at the interface of biology, geochemistry, soil mechanics, and geotechnical engineering. This represents a paradigm shift in geotechnical engineering- until now the accepted view has been to consider the ground as sterile and inert; now engineers are exploring the potential for use of biological and biochemical processes in ground engineering applications. This proposal represents the first steps towards the development of a novel low-carbon, minimal intervention, biologically based technology using engineered fungal networks.

Biological soil crusts in nature (consisting of fungi, bacteria and other organisms) are known to withstand erosion due to water or wind action. This project will investigate filamentous fungi, i.e. fungi which grow hyphae (tube-like structures). It is thought that fungal hyphae behave similar to plant roots - penetrating between soil particles and entangling them -helping to bind soil particles together, but on a smaller scale. Furthermore, fungi can secrete biochemical products, which may also contribute to binding of soil particles. This project will systematically quantify the mechanical benefit of fungal treatment in soils by investigating three different types of fungi and their ability to enhance the behaviour of different soil types. The project will determine the conditions required for rapid fungal network growth to occur and optimise the orientation of hyphal development to give maximum mechanical benefit. The dataset arising from the proposed experimental campaign will act as a springboard for the development of a new range of nature inspired ground improvement technologies.

The research proposed could transform how we consider the design of, development and deployment of ground improvement technologies. Rather than subject the ground to different energy intensive or invasive techniques, this research proposes to 'grow' the required level of treatment through the use of fungal networks. The process could be engineered using external stimuli to orient the hyphal networks as required for site-specific applications. This project will investigate the feasibility of the deployment of fungal networks as a ground improvement technology.

Potential Impact:
This project takes a creative and ambitious approach to ground improvement technologies. The work carried out in this project will result in economic, societal and additional benefits:
1. Economy- It is envisaged that the results from this project will contribute to the emerging field of biogeotechnical engineering. Other biogeotechnical engineering processes have been brought from fundamental laboratory research to deployment on commercial projects in approx.10 years. Through this project and by exploring alternative biological processes and assessing their suitability for deployment in ground engineering, there is an opportunity for the UK ground engineering industry to take the lead in biogeotechnical engineering. It is anticipated that the dataset arising from the proposed experimental campaign will act as a springboard for the development of a new range of nature inspired ground improvement technologies. The development of new products and technologies in the long-term will contribute to the economic competitiveness of the UK and contribute towards the transition of the UK construction sector to low-carbon technologies.

2. Society- The project represents the first step towards the development of a new range of low-carbon ground improvement technologies, which could contribute towards the ultimate goal of developing geotechnical infrastructure more resilient to environmental change. In the long-term, technologies arising from the research carried out in this project could contribute indirectly to enhancing the quality of life for the public, for example via their deployment as flood embankment protection measures. The outcomes of this project are expected to lead to low-cost ground improvement technologies, which involve minimal transportation of materials to site (reducing environmental impacts during treatment), making them suitable for deployment in remote areas and in international development contexts.

3. People - In the short term the project will equip two researchers with skills in soil mechanics, geomicrobiology and geotechnics. Education/research experience in this multi-disciplinary area is necessary to ensure adequately skilled people can lead this research field in the future but also to ensure that arising innovations are deployed in engineering practice.