出典:Wikipedia
出典:『Wikipedia』 (2011/07/01 09:34 UTC 版)
A borehole is the generalized term for any narrow shaft bored in the ground, either vertically or horizontally. A borehole may be constructed for many different purposes, including the extraction of water or other liquid (such as petroleum) or gases (such as natural gas), as part of a geotechnical investigation, environmental site assessment, mineral exploration, temperature measurement or as a pilot hole for installing piers or underground utilities. Boreholes used as water wells are described in more depth in that article.