Earthworks (engineering)
In civil engineering, earthworks are engineering works created through the moving of massive quantities of soil or unformed stone. Engineers need to concern themselves with both issues of geotechnical engineering (such as soil fluidity and friction), and with quantity estimation - to ensure that soil volumes in the cuts match those of the fills, while minimising the distance of movement. In the past, such calculations were done by hand using a slide rule and with methods such as Simpson's rule, but nowdays using a computer and specialised software. Due to the massive amounts of material to be moved — millions of tonnes in the case of large dams — earthwork engineering was revolutionised by the development of the (Fresno) scraper and other earth-moving machines such as the loader, the grader, the bulldozer, the backhoe and the drag line excavator. Typical earthworks include roads, dams, dykes and canals. In military engineering, earthworks are more specifically types of fortifications constructed from soil. Although soil is not very strong, it is cheap enough that huge quantities can be used, generating formidable structures. Examples of older earthwork fortifications include moats, sod walls, motte-and-bailey castles and hill forts. Modern examples include trenches and berms. Archaeology also has an interest in earthworks, including ancient fortifications, but also henges, barrows and other tombs.
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