Impact of climate change in geostructures with particular reference to transport infrastructure

Present and future engineering problems associated with transport infrastructure geostructures require an understanding of soil-atmosphere interaction. Extreme weather attributed to climate change will result in intensified climatic events and seasonal extremes. It is expected that this will result in performance shortcomings of critical transport infrastructure owing to an unprecedented change in hydraulic stresses and the resultant behaviour of geomaterials. Consequently, there will be a loss of productivity, increased maintenance costs, and commuter disruption. In addition, the problem is further complicated by the age of the UK's transport infrastructure network, which in some cases has been subject to more than 150 years of increasing use and development since its initial construction.
As of late 2020, these issues have been brought to national attention by the fatal railway derailment at Stonehaven where an interim report by Network Rail acknowledged that the effects of climate change are advancing faster than initially thought. This means a greater understanding of the impact of climate change on transport infrastructure is crucial if potential geotechnical risks are to be reduced and future resilience increased.
This PhD aims to address these topics by exploring material behaviour - a key science which underpins all engineering projects - of compacted geomaterials used in substructure formation of transport infrastructure. Compacted geomaterials interaction with the atmosphere is complex due to its ability to influence a soils constituent components. Thus, its effect on strength, volume, and water retention behaviour under in-situ conditions is multifaceted. These factors are also temporally variable depending on seasonal and extreme climatic events - i.e. periods of intense rainfall accompanied by extended periods of drought or prolonged precipitation - which are exacerbated by climate change. This will be investigated using a novel approach to laboratory testing, examining in detail the change in stress strain behaviour resulting from the interaction of seasonal variation in hydraulic stress and extreme climatic events under different compacted states and loading regimes. As a result, the behaviour of a chosen compacted soil will be characterised under these contemporary and evolving conditions, providing an intersection between environmental sciences and ground engineering. In addition, an examination of the role of vegetation as a mediator between transport geostructures and the atmosphere and the benefits it could have on curbing the impacts of climate change will be made. Advanced constitutive modelling will be used to holistically apply the findings and numerically simulate the effects of future climatic conditions.
A greater understanding in this area will help optimise asset management used during the transport infrastructure lifecycle and facilitate the development of climate change adaptation to increase network resilience. As such, the research will provide insight required when targeting interventions and undertaking risk management to increase asset lifespan, reduce the potential risk of failure and minimise the carbon impact and cost of overcoming future climatic challenges.