Editing Retaining wall (section)

==Types==

[[File:Retaining Wall Type Function.jpg|840px|thumb|center|Various types of retaining walls]]

===Gravity===
[[File:Gravity Walls.jpg|thumb|Construction types of gravity retaining walls]]
[[File:Crib wall.JPG|thumb|An example of crib wall]]

Gravity walls depend on their mass (stone, concrete or other heavy material) to resist pressure from behind and may have a <!-- "batter" is NOT A TYPO -->'batter' setback to improve stability by leaning back toward the retained soil. For short landscaping walls, they are often made from [[Mortar (masonry)|mortar]]less stone or segmental concrete units (masonry units).<ref name="SEG">{{cite web| title = Segmental Retaining Walls| publisher = [[National Concrete Masonry Association]]| url = http://www.ncma.org/use/srw.html| access-date = 2008-03-24 |archive-url = https://web.archive.org/web/20080304073923/http://www.ncma.org/use/srw.html |archive-date = 2008-03-04}}</ref> Dry-stacked gravity walls are somewhat flexible and do not require a rigid footing. They can be built to a low height without additional materials being inserted, and have concrete added for strength and stability. 
<ref name="DRY">{{cite web| title = Dry Stack Retaining Walls| publisher = [[Australian Landscape Supplies]]| url = https://www.australianlandscapesupplies.com.au/collections/pentablock-modular-concrete-blocks| access-date = 2023-08-12 }}</ref>

Earlier in the 20th century, taller retaining walls were often gravity walls made from large masses of concrete or stone. Today, taller retaining walls are increasingly built as composite gravity walls such as: geosynthetics such as geocell cellular confinement earth retention  or with precast facing; [[gabion]]s (stacked steel wire baskets filled with rocks); crib walls (cells built up log cabin style from precast concrete or timber and filled with granular material).<ref name="soil-mechanics">{{cite book| last = Terzaghi| first = K.| author-link = Karl von Terzaghi| title = Theoretical Soil Mechanics| place = New York| publisher = John Wiley and Sons| year=1943}}</ref>

===Cantilevered===
Cantilevered retaining walls are made from an internal stem of steel-reinforced, cast-in-place concrete or mortared masonry (often in the shape of an inverted T). These walls cantilever loads (like a [[beam (structure)|beam]]) to a large, structural footing, converting horizontal pressures from behind the wall to vertical pressures on the ground below. Sometimes cantilevered walls are buttressed on the front, or include a [[Buttress|counterfort]] on the back, to improve their strength resisting high loads. Buttresses are short [[wing wall]]s at right angles to the main trend of the wall. These walls require rigid concrete footings below seasonal frost depth.  This type of wall uses much less material than a traditional gravity wall.

===Diaphragm wall===
[[Diaphragm wall]]s are a type of retaining walls that are very stiff and generally watertight. Diaphragm walls are expensive walls, but they save time and space, and hence are used in urban constructions.<ref name="Bahrami">{{cite journal |last1=Bahrami |first1=M. |last2=Khodakarami |first2=M.I.  |last3=Haddad |first3=A.|title=3D numerical investigation of the effect of wall penetration depth on excavations behavior in sand |journal=Computers and Geotechnics |date=June 2018 |volume=98 |pages=82–92 |doi=10.1016/j.compgeo.2018.02.009 |s2cid=125625145 }}</ref>

===Sheet piling {{anchor|Sheet piling}} ===
[[File:Spundwand.jpg|thumb|Sheet pile wall]]
{{Main|Larssen sheet piling}}
Sheet pile retaining walls are usually used in soft soil and tight spaces. Sheet pile walls are driven into the ground and are composed of a variety of material including steel, vinyl, aluminum, fiberglass or wood planks. For a quick estimate the material is usually driven 1/3 above ground, 2/3 below ground, but this may be altered depending on the environment. Taller sheet pile walls will need a tie-back [[Earth anchor|anchor]], or "dead-man" placed in the soil a distance behind the face of the wall, that is tied to the wall, usually by a cable or a rod. [[Earth anchor|Anchors]] are then placed behind the potential failure plane in the soil.

===Bored pile ===
[[File:Bored pile retaining wall 2012-03-12 11h19m.JPG|thumb|Bored pile retaining wall in [[Lisbon]], Portugal]]

Bored pile retaining walls are built by assembling a sequence of [[bored pile]]s, followed by excavating away the excess soil.  
Depending on the project, the bored pile retaining wall may include a series of [[earth anchor]]s, reinforcing beams, soil improvement operations and [[shotcrete]] reinforcement layer.
This construction technique tends to be employed in scenarios where sheet piling is a valid construction solution, but where the vibration or noise levels generated by a [[pile driver]] are not acceptable.

===Anchored===

{{See also|Tieback (geotechnical)}}

[[File:Anchored wall.jpg|thumb|Anchored wall in the mountainous region of [[Rio de Janeiro (state)|Rio de Janeiro state]], Brazil]]
An anchored retaining wall can be constructed in any of the aforementioned styles but also includes additional strength using cables or other stays anchored in the rock or soil behind it. Usually driven into the material with boring, anchors are then expanded at the end of the cable, either by mechanical means or often by injecting [[Shotcrete|pressurized concrete]], which expands to form a bulb in the soil. Technically complex, this method is very useful where high loads are expected, or where the wall itself has to be slender and would otherwise be too weak.