Atrench is a type ofexcavation or depression in the ground that is generally deeper than it is wide (as opposed to aswale or abar ditch), and narrow compared with its length (as opposed to a simplehole orpit).[1]
Ingeology, trenches result fromerosion by rivers or by geological movement oftectonic plates. Incivil engineering, trenches are often created to install undergroundutilities such asgas,water,power andcommunication lines. Inconstruction, trenches are dug for foundations of buildings, retaining walls and dams, and forcut-and-cover construction of tunnels. Inarchaeology, the "trench method" is used for searching andexcavating ancientruins or to dig intostrata of sedimented material. Ingeotechnical engineering, trench investigations locate faults and investigate deep soil properties. Intrench warfare, soldiers occupy trenches to protect them against weapons fire and artillery.
Trenches are dug using manual tools such asshovel andpickaxe or heavy equipment such asbackhoe,trencher, andexcavator.
For deep trenches, the instability of steep earthen walls requires engineering and safety techniques such asshoring. Trenches are usually considered temporary structures that are backfilled withsoil after construction or abandoned after use. Some trenches are stabilized using durable materials such asconcrete to create open passages such ascanal and sunken roadways.
Some trenches are created as a result oferosion by running water or byglaciers (which may have long since disappeared). Others, such asrift valleys oroceanic trenches, are created by geological movement oftectonic plates. Some oceanic trenches include theMariana Trench and theAleutian Trench.[2][3] The former geoform is relatively deep (approximately 10 kilometres (6.2 mi)), linear and narrow, and is formed byplate subduction when plates converge.[4]
.jpg)
In thecivil engineering fields of construction and maintenance of infrastructure, trenches play a major role. They are used for installation of underground infrastructure or utilities (such asgas mains,water mains,communication lines andpipelines) that would be obstructive or easily damaged if placed above ground. Trenches are needed later for access to these installations for service. They may be created to search for pipes and other infrastructure whose exact location is no longer known ("search trench" or "search slit"). Finally, trenches may be created as the first step of creating afoundation wall.Trench shoring is often used in trenchworks to protect workers and stabilise the steep walls.
An alternative to digging trenches is to create autility tunnel. Such a tunnel may be dug byboring or by using a trench forcut-and-cover construction. The advantages of utility tunnels are the reduction of maintenance manholes, one-time relocation, and less excavation and repair, compared with separate cable ducts for each service. When they are well mapped, they also allow rapid access to all utilities without having to dig access trenches or resort to confused and often inaccurate utility maps.
An important advantage to placing utilities underground is public safety. Underground power lines, whether in common or separate channels, prevent downed utility cables from blocking roads, thus speeding emergency access after natural disasters such asearthquakes, hurricanes, and tsunamis.[5]
In some cases, a large trench is dug and deliberately preserved (not filled in), often for transport purposes. This is typically done to install depressedmotorways, openrailway cuttings, orcanals. However, these large, permanent trenches are significant barriers to other forms of travel, and often becomede facto boundaries between neighborhoods or other spaces.
Trenches have often been dug for military purposes. In the pre-firearm era, they were mainly a type of hindrance to an attacker of a fortified location, such as themoat around acastle (this is technically called aditch). An early example of this can be seen in theBattle of the Trench, areligious war, one of the earlybattles fought byMuhammad.[6]
With the advent of accurate firearms, trenches were used to shelter troops. Trench warfare and tactics evolved further in theCrimean War, theAmerican Civil War andWorld War I, until systems of extensive main trenches, backup trenches (in case the first lines were overrun) and communication trenches often stretched dozens of kilometres along a front without interruption, and some kilometres further back from the front line. The area of land between trenches in trench warfare is known as "No Man's Land" because it often offers no protection from enemy fire. AfterWW1 had concluded, the trench became a symbol ofWW1 and its horrors.
.jpg)
Trenches are used for searching andexcavating ancientruins or to dig intostrata of sedimented material to get a sideways (layered) view of the deposits – with a hope of being able to place found objects or materials in a chronological order. The advantage of this method is that it destroys only a small part of the site (those areas where the trenches, often arranged in a grid pattern, are located). However, this method also has the disadvantage of only revealing small slices of the whole volume, and modern archeological digs usually employcombination methods.[7]
Trenches that are deeper than about 1.5m present safety risks arising from their steep walls and confined space. These risks are similar those from pits or any steep-walled excavations. The risks include falling, injury fromcave-in (wall collapse), inability to escape the trench, drowning andasphyxiation.[8][9]
{{cite book}}: CS1 maint: others (link)
| Investigation and instrumentation |
| ||||||
|---|---|---|---|---|---|---|---|
| Soil |
| ||||||
| Structures (Interaction) |
| ||||||
| Mechanics |
| ||||||
| Numerical analysis software | |||||||
| Related fields | |||||||
