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Worldwide efforts are under way to accelerate improvements in the technology of underground construction and are likely to be stimulated as a result of the 1970 OECD International Conference recommending improvement as government policy. The endeavour involves specialists such as geologists, soil- and rock-mechanics engineers, public-works designers, mining engineers, contractors, equipment and materials manufacturers, planners, and also lawyers, who aid in the search for more equitable contractual methods to share the risks of unknown geology and resulting extra costs. Many improvements and their early applications have been previously discussed; others are briefly mentioned here, including several that have ... (100 of 18283 words)
Aspects of the topic tunnels and underground excavations are discussed in the following places at Britannica.
Articles from Britannica encyclopedias for elementary and high school students.
When natural obstacles-such as mountains, hills, or rivers-block the path proposed for a railway, highway, or pipeline, engineers bore tunnels through or under the obstacles. Structures built as trenches and later covered are also often called tunnels. Tunnels that bring water from reservoirs to cities may be called aqueducts (see
aqueduct). Mass-transit railway tunnels constructed under cities to relieve crowded streets are known as subways."tunnels and underground excavations." Encyclopædia Britannica. Encyclopædia Britannica Online. Encyclopædia Britannica, 2011. Web. 25 Mar. 2011. <http://www.britannica.com/EBchecked/topic/609297/tunnel>.
tunnels and underground excavations. (2011). In Encyclopædia Britannica. Retrieved from http://www.britannica.com/EBchecked/topic/609297/tunnel
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