This sketchup video tutorial looks at two different ways to make a geodesic tunnel, this is actually a very simple process if we want to make a tunnel based on a 2v dome. However Paul also explains why it's not so simple to make tunnels as you go up in frequency.
Take a look at Paul's other videos showing how to build a 2v tunnel.
Part 1. http://youtu.be/zH8uWNV5hDo
Part 2. http://youtu.be/9bWKCI0WLRk
Part 3. http://youtu.be/pti4rHSd1Yg
Plans for a 2v tunnel dome are available here: http://www.geo-dome.co.uk/domeshop/article.asp?Uname=292
The preferred why to construct the tunnel section is to use an anti-prism with 20 equilateral triangles, it is possible to triangulate a prism with ten sides but the result isn't as aesthetically pleasing, details of one here: http://geo-dome.co.uk/article.asp?uname=triacon_tunnel
