Subscribe for full online access and get...
- Full, instant access to all stories
- Customised email alerts straight to your inbox
- Monthly print magazine
For the best possible experience using our website we recommend you upgrade to a newer version or another browser.
The elements for the immersed Busan-Geoje tube tunnel are a huge 10m high by 26.5m wide by 180m long. But the smallest of cracks in the concrete could cause disaster.