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A tunnelling shield is a protective structure used during the excavation of large, human-made tunnels. When excavating through ground that is soft, liquid, or otherwise unstable, there is a potential health and safety hazard to workers and the project itself from falling materials or a cave-in. A tunnelling shield can be used as a temporary ...
Tunnel boring machine. A tunnel boring machine (TBM), also known as a "mole" or a "worm", is a machine used to excavate tunnels. Tunnels are excavated through hard rock, wet or dry soil, or sand, each of which requires specialized technology. Tunnel boring machines are an alternative to drilling and blasting (D&B) methods and "hand mining".
Tunnel Construction. Tunnels are dug in types of materials varying from soft clay to hard rock. The method of tunnel construction depends on such factors as the ground conditions, the ground water conditions, the length and diameter of the tunnel drive, the depth of the tunnel, the logistics of supporting the tunnel excavation, the final use and shape of the tunnel and appropriate risk management.
A tunnel is an underground or undersea passageway. It is dug through surrounding soil, earth or rock, or laid under water, and is usually completely enclosed except for the two portals common at each end, though there may be access and ventilation openings at various points along the length.
The New Austrian tunneling method (NATM), also known as the sequential excavation method (SEM) or sprayed concrete lining method[1] (SCL), is a method of modern tunnel design and construction employing sophisticated monitoring to optimize various wall reinforcement techniques based on the type of rock encountered as tunneling progresses.
Brunel's shield was rectangular and comprised 12 separate, independently moveable frames; the Greathead solution was cylindrical, and the "reduction of the multiplicity of parts in the Brunel shield to a single rigid unit was of immense advantage and an advance perhaps equal to the shield concept of tunneling itself", [10] though the face was ...
Microtunneling. Microtunneling or microtunnelling is a tunnel construction technique used to construct utility tunnels from approximately 0.5–4 m (1 ft 8 in – 13 ft 1 in) in diameter. Because of their small diameter, it is not possible to have an operator driving the tunneling machine, so they have to be remotely operated.
t. e. In computer networks, a tunneling protocol is a communication protocol which allows for the movement of data from one network to another. It can, for example, allow private network communications to be sent across a public network (such as the Internet), or for one network protocol to be carried over an incompatible network, through a ...