Road cutting

In civil engineering, a cut or cutting is where soil or rock from a relative rise along a route is removed. The term is also used in river management to speed a waterway's flow by short-cutting a meander.

Cuts are typically used in road, rail, and canal construction to reduce the length and grade of a route. Cut and fill construction uses the spoils from cuts to fill in defiles to cost-effectively create relatively straight routes at steady grades.

Cuts are used as alternatives to indirect routes, embankments, or viaducts. They also have the advantage of comparatively lower noise pollution than elevated or at-grade solutions.

History

Talerddig cutting through the granite 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

The term cutting appears in the 19th century literature to designate rock cuts developed to moderate grades of railway lines.[1] Railway Age's Comprehensive Railroad Dictionary defines a cut as "a passage cut for the roadway through an obstacle of rock or dirt".[2]

Creation

Open-cut station of the New York City Subway

Cuts can be created by multiple passes of a shovel, grader, scraper or excavator, or by blasting.[3] 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. The use of cuttings often provides byproducts as a form of mineral extraction, commonly sand, clay or gravel; the cost of building drains, reinforcing banks against landslide and a high water table are factors which commonly limit its use in certain areas.

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 or the railway. 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]

A ledge is a cut in the side of a cliff well above the bottom of a gorge

Lock cut

A lock cut on the River Thames at Bray Lock, Berkshire. The tall wooden poles are designed for boats to tie on to while awaiting entry into the lock.

A lock cut is a section of a river or other inland waterway immediately upstream and downstream of a lock which has been modified to provide locations for boats to moor while waiting for the lock gates to open or to allow people to board or alight vessels.

Notable cuts

Canal

Rail

Excavation of Olive Mount cutting, 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 (370,000 m3) of sandstone.

Road

See also

References

  1. ^ Alexander Smith (1875) A new history of Aberdeenshire
  2. ^ 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.
  3. ^ 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.
  4. ^ Nichols and Day, Moving the Earth, p. 8.16.