Retaining walls are built to retain soil, land or structures. They retain soil between different elevations where the landscape needs to be altered, however, the specific needs may be different depending on the project. Retaining walls are used in residential construction projects through to larger infrastructural and mining projects. They can be constructed in many sizes and each type of retaining wall is best suited for different project sizes.
Anchored retaining walls
What is it?
An anchored retaining wall is anchored to the rock or soil behind it using cables. Another name for this type of wall is a tie-back system which increases stability and helps equip the walls to handle more load. They are often used with cantilever walls, piled-creating walls, sheet piles, tangent walls and others. They can be used for commercial projects, or used for larger mining projects as the anchored system helps stabilise large rock walls for safety purposes.
Sizes
Generally, anchored walls are slimmer than others like gravity walls and cantilever retaining walls, making it an excellent option for those working in areas with limited space or where a thin wall is required. This type of retaining wall should be made to resist bearing capacity failure because the walls are very thin. Regardless of its thin size, this retaining wall can be built to considerably high heights and concerns regarding overturning and sliding pressure are overcome using tiebacks.
Materials
Anchored retaining walls are made of cables that are linked to the soil or rock. The cables are usually made from strong steel and a deadman is used to anchor one end of the cable into and the other is attached to a wall.
Gravity retaining walls
What is it?
Gravity retaining walls are one of the oldest and usually most commonly used types of wall. The structure gets its name because it relies on its own weight to stand up hence the use of gravity in its name.
Sizes
The size of the wall can vary however it should aim to be a minimum of 50 to 60% in thickness of the height of the wall. It might be larger if a slop or surcharge pressure is evident on the wall.
Materials
This wall is made from stone or similar heavy material and uses its own mass to resist pressure from the retained material. The gravity wall includes gabions, concrete cribs, boulders and large precast concrete block walls.
Sheet pile retaining walls
What is it?
A sheet pile retaining wall is a type of retaining wall constructed to retain water, earth or other filling materials. A retaining wall of this nature is thinner in comparison to masonry walls. The below list shows example uses of sheet pile retaining walls:
- Waterfront structures
- Building diversion dams
- Riverbank protection
- Retaining the sides of cuts made in the earth
Sizes
This type of retaining wall is a narrow type of structure and is most commonly installed close to the boundary of a site to utilise site space. The retaining wall is usually used for heights 6m or less and is available in numerous sizes and weights.
Materials
This kind of retaining wall can be made using a range of materials including wood, timber, concrete, and steel. Choosing to use steel on your piling retaining walls is beneficial as it is environmentally friendly. This is because when the construction is completed the sheet piles are extracted and reused on other projects.
Cantilever retaining walls
What is it?
Cantilever retaining walls are utilised to retain large amounts of soil on a construction site. This is a good option as it uses less concrete than gravity walls, however, requires a lot more attention when designing and constructing. They can be constructed on-site of the project or can be precast in a factory.
Sizes
Cantilever walls are usually about 25 feet tall and have a thinner stem which also uses the weight of the backfill soil to give resistance to overturning and sliding. The cantilever retaining wall is arguably the most commonly used structure on earth-retaining projects.
Materials
This type of retaining wall is created using thin-stem steel-reinforced concrete and a base slab. The base of this structure is divided into parts including the heel and toe. The heel is situated under the backfill and is a part of the base.
How much do the different retaining wall types cost?
The cost of the retaining wall differs depending on the type of wall it is. Other factors contributing to the price include the time taken to install, the labour expertise needed and the location of the project. Anchored retaining walls need to be professionally installed. This is because cables are secured into the ground using pressurised concrete. You can build a gravity retaining wall yourself .
However, if you are looking at building a larger wall then a professional landscaper or builder will need to be hired. You might also need a structural engineer if the wall is taller than 1 meter. The extra labor will result in an increase in the price of the service. You can construct sheet pile retaining walls yourself which will help decrease the cost.
However, you must be confident in your skills to ensure this is done safely. A cantilever retaining wall uses less concrete than a gravity wall, however, they need to be designed specifically meaning it is not a DIY project.
Find a retaining wall contractor
If you don’t have the time to find a qualified retaining wall builder yourself then don’t worry! iseekplant is Australia’s largest online construction marketplace with thousands of contractors listed, so if you want to find retaining wall costs that suit you, look no further than iseekplant.
Get in touch with our expert team at 1300 691 912, or email our Projects team with your specifications. We will help you find retaining wall builders who will meet the requirements of your next project.