This started as a Christmas discussion and when I went to look, I could not easily find anything on the physics of ice roads. So, I thought I’d try to work out some of the basics from first principles and a bit of guess work.
Let’s start with an assumed 10tonne vehicle. If we assume the density of ice is 9/10 of normal water, then if 100tonnes of ice is pushed down into the water, it will support the weight of a 10 tonne lorry. If we then assume the ice depresses by 10cm (which seems a lot), then the area that is pressed down is around 1000m² or 31 x 31m..
If I were to guess, I’d say that typically ice sheets break so that the length is around 10x the thickness (total guess!!). If true that suggests that the ice needs to be at least 3m thick to produce slabs over 30m x 30m.
However, lorries don’t sit on the ice, instead they drive over it. And indeed I’ve seen rules that say “don’t stop on the ice!!” Continue reading