Soil-mycelia systems for slope stabilisation

Heavy rainfall is a well-known trigger of shallow landslides and slope failures in the UK and globally. As water infiltrates into partially saturated soil, pore water pressures increase and the shear strength of the soil reduces. Globally, up to 350 fatal landslides are triggered by rainfall each year causing thousands of deaths.

In the UK up to 80 landslides and slope failures are recorded per month during periods of heavy rainfall. These events cause major disruption to transport networks with a range of economic and social impacts. The direct costs of implementing emergency repairs are substantial: the cost of routine maintenance of the rail network in 2016/17 was £154M and emergency repairs can cost 100 times the cost of maintenance works.

The cost of implementing remedial measures for natural hillslopes is also substantial, e.g. Transport Scotland spent £13.3M at the Rest & Be Thankful site along the A83 in Scotland between 2007-2019. UK climate projections predict warmer, wetter winters and hotter, drier summers with increasing winter rainfall and significant increases in rainfall intensity.

Our changing climate will further impact on the stability of natural and engineered slopes in the UK, driving the need for novel approaches for their management and maintenance.

This fellowship programme focuses on the development of a range of low-cost, low-carbon minimal intervention ground engineering technologies which mimick the growth of fungal mycelia that occurs in natural ecosystems. This project will investigate filamentous fungi, fungi that grow as hyphae (tube-like structures). The collective mass of hyphae of a fungus is known as the mycelium.

As the mycelium grows through the soil, it forms a natural geotextile, entangling soil particles within its mesh. The mycelium also secretes biochemical products, which can alter the wettability of soils and contribute to 'gluing' soil particles together. The aim of this fellowship is to develop five fungal biotechnologies which can enhance slope stability via various mechanisms including: (i) reducing water infiltration (ii) enhancing soil cohesion and resistance to surface erosion and (iii) providing tensile reinforcement.

These fungal biotechnologies will be based on engineering five types of soil-mycelia systems with differing architecture. The hydro-mechanical performance of these soil-mycelia systems will be optimised by controlling nutrient supply and positioning to orient mycelium growth. This fellowship will enable a systematic demonstration of the performance of soil-mycelia systems for ground engineering from lab-scale to field-scale.

This ambitious and adventurous programme of research will be underpinned by the creation of an internationally-leading research team at Strathclyde in this novel avenue of biogeotechnical engineering. The proposed fungal biotechnologies could transform ground engineering approaches to slope stabilisation. With the ability to 'grow' soil modification comes the opportunity to treat far greater volumes of soil; these technologies could be deployed for landslide mitigation on a catchment-scale, for improved resilience of engineered infrastructure, for erosion control and desertification.