Editing Retaining wall (section)

==Alternative retaining techniques==

===Soil nailing===

{{main|Soil nailing}}
Soil nailing is a technique in which soil slopes, [[Earthworks (engineering)|excavations]] or retaining walls are reinforced by the insertion of relatively slender elements – normally steel reinforcing bars. The bars are usually installed into a pre-drilled hole and then [[grout]]ed into place or drilled and grouted simultaneously. They are usually installed untensioned at a slight downward inclination. A rigid or flexible facing (often sprayed concrete) or isolated soil nail heads may be used at the surface.

===Soil-strengthened===
A number of systems exist that do not consist of just the wall, but reduce the earth pressure acting directly on the wall. These are usually used in combination with one of the other wall types, though some may only use it as facing, ''i.e.'', for visual purposes.
[[File:Retaining wall in dale, Israel.jpg|thumb|Stones of retaining wall used in preventing soil run-off in dale]]

====Gabion meshes====
{{Main|Gabion}}
This type of soil strengthening, often also used without an outside wall, consists of [[wire]] [[mesh]] "boxes", which are filled with roughly cut stone or other material. The mesh cages reduce some internal movement and forces, and also reduce erosive forces. 
Gabion walls are free-draining retaining structures and as such are often built in locations where ground water is present. However, management and control of the ground water in and around all retaining walls is important.

===Mechanical stabilization===

{{main|Mechanically stabilized earth}}

Mechanically stabilized earth, also called MSE, is soil constructed with artificial reinforcing via layered horizontal mats ([[geosynthetics]]) fixed at their ends. These mats provide added internal shear resistance beyond that of simple gravity wall structures. Other options include steel straps, also layered. This type of soil strengthening usually needs outer facing walls (S.R.W.'s – Segmental Retaining Walls) to affix the layers to and vice versa.<ref>
[http://geostone.com/CAD/8vs4-16ft_batter.jpg JPG image]. geostone.com</ref>

The wall face is often of precast concrete units<ref name="SEG"/> that can tolerate some differential movement. The reinforced soil's mass, along with the facing, then acts as an improved gravity wall. The reinforced mass must be built large enough to retain the pressures from the soil behind it. Gravity walls usually must be a minimum of 50 to 60 percent as deep or thick as the height of the wall, and may have to be larger if there is a slope or surcharge on the wall.

[[Cellular confinement systems|Cellular confinement systems (geocells)]] are also used for steep earth stabilization in gravity and reinforced retaining walls with geogrids. Geocell retaining walls are structurally stable under self- weight and externally imposed loads, while the flexibility of the structure offers very high seismic resistance.<ref>{{cite journal|author=Leshchinsky, D. |year=2009|url=http://geosyntheticsmagazine.com/2009/08/01/research-and-innovation-seismic-performance-of-various-geocell-earth-retention-systems/|title=Research and Innovation: Seismic Performance of Various Geocell Earth-retention Systems|journal=Geosysnthetics|volume= 27|issue= 4|pages= 46–52}}</ref> The outer fascia cells of the wall can be planted with vegetation to create a [[green wall]].