Cut (earthmoving)

Road cutting

In civil engineering, a cut or cutting is where soil or rock material from a hill or mountain is cut out to make way for a canal, road or railway line.

Talerddig cutting through the Cambrian Mountains, Wales in 2001. Created as part of the Newtown and Machynlleth Railway, with a depth of 120 feet (37 m), it was the deepest cutting in the world at the time of its opening in the early 1860s. The original near-vertical sides have since been trimmed back

In cut and fill construction it keeps the route straight and/or flat, where the comparative cost or practicality of alternate solutions (such as diversion) is prohibitive. Contrary to the general meaning of cutting, a cutting in construction is mechanically excavated or blasted out with carefully placed explosives. The cut may only be on one side of a slope, or directly through the middle or top of a hill. Generally, a cut is open at the top (otherwise it is a tunnel). A cut is (in a sense) the opposite of an embankment.

Open-cut station of the New York City Subway

When used in reference to transportation routes, it reduces the grade of the route.

Cuts can be created by multiple passes of a shovel, grader, scraper or excavator, or by blasting.^[1] One unusual means of creating a cut is to remove the roof of a tunnel through daylighting. Material removed from cuts is ideally balanced by material needed for fills along the same route, but this is not always the case when cut material is unsuitable for use as fill.

The word is also used in the same sense in mining, as in an open cut mine.

History

The term cutting appears in the 19th century literature to designate rock cuts developed to moderate grades of railway lines.^[2] Railway Age's Comprehensive Railroad Dictionary defines a cut as "a passage cut for the roadway through an obstacle of rock or dirt."^[3]

Types of cut

There are at least two types of cut, sidehill cut and through cut. The former permits passage of a transportation route alongside of or around a hill, where the slope is transverse to the roadway. A sidehill cut can be formed by means of sidecasting, i.e., cutting on the high side balanced by moving the material to build up the low side to achieve a flat surface for the route. In contrast, through cuts, where the adjacent grade is higher on both sides of the route, require removal of material from the area since it cannot be dumped alongside the route.^[4]

Notable cuts

Notable canal cuts

• Culebra Cut (Gaillard Cut) on the Panama Canal
• Dawesville Cut

Notable railway cuts

Excavation of Olive Mount, Liverpool. Watercolour by T.T.Bury (1833) The cutting was 20 ft (6.1 m) wide and 70 ft (21.3 m) deep. Construction required the removal of 480,000 cubic yards of sandstone.

• Olive Mount cutting, Liverpool
• Bergen Hill
• Duffy's Cut
• Talerddig cutting
• Windmill Hill Cutting
• Hellfire Pass

Notable roadway cuts

• Sideling Hill Cut on I-68
• Pikeville Cut-Through on U.S. Route 23 in Kentucky

See also

• Cut-and-cover
• Embankment (transportation)
• Trench
• Dashrath Manjhi
• Flying arch, use of a dummy arch bridge to stabilise cutting walls against landslip

References

1. Herbert L. Nichols, Jr., and David A. Day, P.E., Moving the Earth: The Workbook of Excavation, 5th ed. (New York: McGraw-Hill, 2005), pp. 8.16 et seq.
2. Alexander Smith (1875) A new history of Aberdeenshire
3. Robert G. Lewis et al., eds., Railway Age's Comprehensive Railroad Dictionary (Omaha, Neb.: Simmons-Boardman Books, 1984), p. 48. This reference does not include a definition for the corresponding term fill.
4. Nichols and Day, Moving the Earth, p. 8.16.