| Tunnelling Techniques Used To Create Tunnels|
|Tunnels have been created for many important and useful reasons. For example, tunnels have been created to greatly cut down on journey times, aqueducts to supply water for consumption, hydroelectric stations, sewers, and basic power/telecommunication cables.|
Life without tunnels in the modern world would be very different indeed - and we often take these great engineering feats for granted. This article looks at the basic processes used to create tunnels and improve our lives for the better.
Tunnel boring machines (which are often called TBMs) were a major breakthrough in the tunnelling industry, which has automated the entire tunnelling process and drastically reduced tunnelling costs. Boring is basically the process of enlarging a hole that has already been previously drilled by means of a single-point cutting tool.
Drilling and blasting
Shorter tunnels tend to be less economical to construct with an expensive TBM and are constructed by the drill and blast alternative. It means drilling and then detonating an explosive to cause the rock to collapse.
This is a simple method of construction for shallow tunnels where a trench is excavated and roofed over with an overhead support system strong enough to carry the load of what is to be built above the tunnel.
Hydraulic jacks push specially made piping through the ground behind a tunnel boring machine or shield. This technique is commonly used to create small tunnels under roads or railways etc.
A box shaped tunnel is used here, which is the major difference to the pipe jacking method. However, jacked boxes can also be a much larger span than a pipe jack.
Manually digging tunnels in strong clay-based soil, which is obviously can't be used on harder materials. This technique was actually very effective during World War II by the British to avoid detection - as it was a quiet process with no drills involved.