Tunnelling Methods

What is a tunnel???
According to Wikipedia, a tunnel is an underground passageway which is completely enclosed except for openings for egress, commonly at each end.

Tunnel construction methods:

• Classical methods

• Mechanical drilling/cutting

• Cut-and-cover

• Drill and blast

• Shields and tunnel boring machines (TBMs)

• New Austrian Tunnelling Method (NATM)

• Immersed tunnels

• Special methods (Tunnel jacking, etc.)

• The process for bored tunnelling involves all or some of the following operations:

• Probe drilling (when needed)

• Grouting (when needed)

• Excavation (or blasting)

• Supporting

• Transportation of muck

• Lining or coating/sealing

• Draining

• Ventilation

Source: <a href="https://theconstructor.org/" target="_blank" rel="nofollow noopener noreferrer">The Constructor – The Construction Encyclopedia</a>

Classical Methods

• Among the classical methods are the Belgian, English, German, Austrian, Italian and American systems. These methods had much in common with early mining methods and were used until last half of the 19th century.

• Excavation was done by hand or simple drilling equipment.

• Supports were predominantly timber, and transportation of muck was done on cars on narrow gauge tracks and powered by steam.

• Progress was typically in multiple stages i.e. progress in one drift, then support, then drift in another drift, and so on.

• The lining would be of brickwork.

These craft-based methods are no longer applicable, although some of their principles have been used in combination up to present day. Nevertheless some of the world’s great tunnels were built with these methods.

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English method

(crown-bar method) started from a central top heading which allowed two timber crown bars to be hoisted into place, the rear ends supported on a completed length of lining, the forward ends propped within the central heading. Development of the heading then allowed additional bars to be erected around the perimeter of the face with boards between each pair to exclude the ground. The system is economical in timber, permits construction of the arch of the tunnel in full-face excavation, and is tolerant of a wide variety of ground conditions, but depends on relatively low ground pressures.


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in india what are the tunnelling methods are used?in transport engineering route map analysis is there due to purpose of cost control,in case of any obstacle chance of tunell the mountains instead of that we move to another route.recently in india where tunnel work is done

which method is best,in what work tunelling is done mostly

I do not know much about Tunnelling methods but see this. This was a very hard task. Engineers completed it superbly. It was very hard indeed. Also see related searches regarding Konkan railways tunnelling.

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