Most of the conventional materials, processes and techniques used by geotechnical engineers for ground improvement are associated with the emission of greenhouse gases. Global targets for reducing carbon emissions therefore pose a direct challenge to research and practice in the field of geotechnical engineering and has led to the development of interdisciplinary approaches seeking alternative low carbon technologies that are resilient to climate change. This thesis presents a novel, potentially low-carbon technique involving the use of fungal hyphal networks of Pleurotus ostreatus (P. ostreatus) for ground engineering applications. An investigation was carried out to understand the range of environmental conditions suitable for growth of P. ostreatus in sand. Subsequently, the influence of the growth of P. ostreatus on the hydraulic and mechanical behaviour of sand was explored, in particular the influence on soil wettability, soil water retention curve, infiltration behaviour, saturated hydraulic conductivity and the stress-strain behaviour of sands. In addition, the influence of growth of P. ostreatus on the erodibility of sand was assessed using the Jet erosion test. The results presented in this thesis demonstrate that the treatment of sand with P. ostreatus (i) induced extreme water repellency, (ii) caused a shift of the soil water retention curve increasing the air entry value from ~0.6 to 6 kPa (iii) reduced the rate of infiltration of water into sand (iv) lowered saturated hydraulic conductivity by one order of magnitude from 1.3 x 10-4 to 3.1 x 10-5 ms-1 (v) inhibited the development of dilatancy during shearing with an associated loss of peak shear strength and (vi) significantly improved the resistance of sand to erosion. These results provide for the first time, evidence of the influence of the growth of fungal hyphae on the hydro-mechanical behaviour of soils within a geotechnical engineering context. The findings of this thesis implies that there is the potential to deploy fungal hyphal networks as a low carbon technique in areas of ground improvement where resistance of surface erosion and/or the creation of a semi-permeable barrier is required.
|Date of Award||7 Jun 2019|
- University Of Strathclyde
|Sponsors||University of Strathclyde|
|Supervisor||Grainne El Mountassir (Supervisor) & Charles Knapp (Supervisor)|