Types of Retaining Walls

Gravity retaining walls are the simplest and one of the original types. They rely solely on their weight and mass to resist the lateral earth pressure exerted by soil. Typically made from concrete or masonry blocks, gravity walls are thick at the bottom and taper towards the top. They can handle substantial loads and are often used in situations where heights are moderate. Their robust construction eliminates the need for additional retaining wall reinforcement.

Cantilever retaining walls use a thinner and more efficient design. They consist of a vertical stem and a horizontal base slab, which sits under the backfill. Made from reinforced concrete with an L or T-shaped foundation, this wall type leverages the weight of the wall and foundation to counteract the lateral forces acting on it. They can be constructed onsite or offsite (precast). Cantilever walls are suitable for heights up to 10 metres and provide excellent strength while minimising material use.

Sheet pile retaining walls consist of long, slender sections, made from steel, precast concrete, vinyl or timber. The interlocking steel sheets are driven or hammered into the ground to create a barrier against soil or water. Sheet piling can be a permanent or temporary retaining wall solution in most types of soil. It is often used in building foundations, underground structures and marine applications, providing good resistance to lateral forces. Sheet pile walls are also known for durability and effectiveness in tight spaces.

Anchored retaining walls are designed to extend the support provided by the wall. They are constructed by driving anchors deep within the earth, which are connected to the wall itself through cables or rods, and then filled with concrete. This type of wall is particularly useful in scenarios where space is limited and a thin structure is required. Anchored walls can support greater heights while resisting lateral forces effectively. They are often utilised in urban environments or locations where excavation is challenging, offering a flexible and robust solution.

Mechanically Stabilised Earth (MSE) retaining walls utilize layers of reinforced soil to create a stable structure. Layers of geosynthetic materials, such as metallic strips or mesh, are combined with soil to improve the wall’s stability. This wall type can easily adapted to different soil conditions. It also provides an economical and cost-effective solution for larger structures. MSE walls are frequently used in highway construction and bridge abutments. Their versatility and ability to blend with surrounding landscapes are significant benefits.

Geogrid retaining walls are similar to MSE walls, but utilise geogrids. This refers to geosynthetic material specifically designed to reinforce the soil behind the wall. These geogrids are placed horizontally between wall courses and create strategic interlocks, increasing the wall’s overall strength. Geogrid walls are ideal for areas with weaker soil conditions or where additional lateral support is necessary. They are environmentally friendly options that allow for landscape integration and aesthetic customisation.

Gabion basket retaining walls are a type of gravity retaining wall, consisting of multi-celled, rectangular wire mesh baskets, which are typically filled with earth or rocks. They are made to construct erosion control structures and allow for drainage. Gabion basket walls are often used in agricultural and landscaping projects due to their natural appearance and permeable properties, making them an environmentally friendly choice. They are also effective for lower heights and can be easily constructed and modified as needed.