Structural behaviour of shotcrete in hard rock tunnels
Andreas Sjölander has investigated the structural behaviour of fibre-reinforced shotcrete used as rock support. As part of the project, an important tool that can be used in future studies has been developed. Hopefully, the results can be a step towards reducing the use of shotcrete in tunnels and scaling down the overuse that we normally see today.
What is the topic of your Doctoral Thesis?
The topic for my doctoral thesis was to investigate the structural behaviour of fibre-reinforced shotcrete used as rock support. More specifically, I’ve looked at how variations in shotcrete thickness and bond strength affects the structural behaviour and capacity.
Why did you choose this topic?
As with most Ph.D prjects, the topic of the project was already set. However, I wanted my project to involve large structures, damage mechanics and concrete so this project was a perfect match.
What are the most important results?
With numerical simulations we have been able to verify the failure mechanisms for a bolt-anchored shotcrete lining. This is one of the fundamental aspects for the design of a shotcrete lining and have previously been based on observation of experimental results. The numerical framework that we have developed to study this is an important tool that can be used in future studies.
Who will benefit from your results? What kind the impact may it have on surrounding society?
In the future I hope that we can reduce the use of shotcrete in our tunnels and that we can scale down the overuse that we normally see today. This will save money and decrease the environmental impact of the tunnel. The results in my thesis is a small step in that direction but we need more research and especially more experimental testing before we can reach this point.
What will you do next?
I’ve just started a position as a post-doctor at the Division of Concrete Structures at KTH. Currently I work with two projects; TACK, that focus on the inspection of tunnels and that aims to generate an autonomous inspection based on deep-learning and photogrammetry. In the other project, we will investigate if other types of fibres, e.g. basalt or synthethic, can be used as reinforcement in our tunnels.
Andreas Sjölander defended his doctoral thesis Structural behaviour of shotcrete in hard rock tunnels in June 2020 in the subject of Civil and Architectural Engineering, specialization Concrete Structures.