Femern tunnel - one design challenge?

The Femern tunnel – 18 km underwater tunnel connection between Denmark and Germany – the worlds longest immersed tunnel project. A 55 billion kroner project!!!

Tunnel elements are constructed on shore, floated out and sunk into place. The tunnel elements are connected subsea and require extreme accuracy to keep the connection water tight.

I will in this video explain one of the biggest design challenges of the project - soil swelling.

Uneven swelling of the soil may lead to cracking of the tunnel.

Interesting paper:
https://www.e3s-conferences.org/articles/e3sconf/pdf/2019/18/e3sconf_isg2019_05004.pdf

Soil report for the real nerds:
https://www.yumpu.com/en/document/read/20787278/ground-investigation-report-may-2011-femern

Beautiful video:
https://www.youtube.com/watch?v=XmP9Ez-u9SM

Видео Femern tunnel - one design challenge? канала TheGeotechEngineer