Trench

A trench is a type of <a href="/facts/Digging/FG5P8Q64">excavation</a> or depression in the ground that is generally deeper than it is wide (as opposed to a <a href="/facts/Swale_(landform)/X8DtobwV">swale</a> or a <a href="/facts/Bar_ditch/nQU4Yz8m">bar ditch</a>), and narrow compared with its length (as opposed to a simple <a href="/facts/Hole/Yx0j4LSV">hole</a> or <a href="/facts/Trapping_pit/lUNwqQrR">pit</a>). 
In <a href="/facts/Geology/WGvVRIYF">geology</a>, trenches result from <a href="/facts/Erosion/gaGJXy0W">erosion</a> by rivers or by geological movement of <a href="/facts/Tectonic_plates/CvbfSfeC">tectonic plates</a>. In <a href="/facts/Civil_engineering/avh5kEq2">civil engineering</a>, trenches are often created to install underground <a href="/facts/Utilities/BzslJKc3">utilities</a> such as <a href="/facts/Pipeline_transport/gEmKcFhD">gas</a>, <a href="/facts/Water_distribution_system/7nW2yBBh">water</a>, <a href="/facts/Underground_power_lines/LpYt47lj">power</a> and <a href="/facts/Undergrounding/LpYt47lj">communication</a> lines. In <a href="/facts/Construction/58eqDhy9">construction</a>, trenches are dug for foundations of buildings, retaining walls and dams, and for <a href="/facts/Tunnel_construction/5t1Pfh7l">cut-and-cover</a> construction of tunnels. In <a href="/facts/Archaeology/K3Q5P38R">archaeology</a>, the "trench method" is used for searching and <a href="/facts/Excavation_(archaeology)/D11k38ob">excavating</a> ancient <a href="/facts/Ruin/uporUru9">ruins</a> or to dig into <a href="/facts/Stratum/w5D4VAwa">strata</a> of sedimented material. In <a href="/facts/Geotechnical_engineering/Nw55uq9R">geotechnical engineering</a>, trench investigations locate faults and investigate deep soil properties. In <a href="/facts/Trench_warfare/GXDoLeRJ">trench warfare</a>, soldiers occupy trenches to protect them against weapons fire and artillery. 
Trenches are dug using manual tools such as <a href="/facts/Shovel/BkavGNM7">shovel</a> and <a href="/facts/Pickaxe/FUw1s7fk">pickaxe</a> or heavy equipment such as <a href="/facts/Backhoe/YD09aPtX">backhoe</a>, <a href="/facts/Trencher_(machine)/ggVAzw1w">trencher</a>, and <a href="/facts/Excavator/4WNsUkjs">excavator</a>.
For deep trenches, the instability of steep earthen walls requires engineering and safety techniques such as <a href="/facts/Trench_shoring/rBTRTDV1">shoring</a>. Trenches are usually considered temporary structures that are backfilled with <a href="/facts/Soil/5Ddpr3QM">soil</a> after construction or abandoned after use. Some trenches are stabilized using durable materials such as <a href="/facts/Concrete/K6whGVNx">concrete</a> to create open passages such as <a href="/facts/Canal/pBE8LsJx">canal</a> and sunken roadways.

Trench open-in-new

Trench