WWII tunnels under the White Cliffs of Dover opened

Exploring German WW2 tunnels .What is inside ?

The critical factor in blasting in tunnels is the lack of an available free surface towards which breakage can occur (only the tunnel heading itself). The principle behind tunnel blasting is to first create an opening by means of a cut, usually at the centre, which provides a breaking surface for the surrounding holes.On the other hand, a common misconception is that the only step required to control blasting damage is to introduce pre-splitting or smooth blasting techniques. However, controllin