They dug! As they were digging they used wood and bits of scrap metal (quite hard to come by, as they were needed to make guns) to hold up the tunnel and stop a cave-in.
Large earth moving equipment, explosives, drilling equipment, tunneling equipment, etc.
The 3 key technology the Axis used during World War 2 are:TanksGunsBombs
during World War II
the only one I can think of right now is the tank
Technology developed during the war was used for consumer products.
This is a pretty broad based question. A lot of technology wasn't used in WW1, primarily because it hadn't been developed. It would be easier to ask what technology was used.
Scanning tunneling electron microscope
genetic engineering
Sapping referred to the method of digging tunnels underground to undermine enemy lines or defensive positions during World War 1. It allowed troops to approach their targets unseen and launch surprise attacks. Tunneling, on the other hand, specifically referred to the practice of constructing tunnels by specialist tunneling companies for various purposes, such as mining beneath enemy positions to plant explosives. Both tactics were used by both sides to gain an advantage in trench warfare.
Every country that participated in WW1 used technology.
in the baking world industry technology is used in the testing of ingredients and equipment
I think that was the trench warfare stuff, not sure though.