Any construction project that involves retaining soil and preventing erosion must build a concrete monolithic retaining wall. Because of its strength and longevity, this kind of wall is a great option for both commercial and residential settings. Knowing the proper techniques for building a monolithic concrete retaining wall is crucial, regardless of whether you’re trying to support a large earthwork or terrace a sloped garden.
Make sure you have the necessary supplies and equipment before you start by making a thorough plan. The first step in the process is designing the wall to meet the unique requirements of your site, which includes considering the type of soil, drainage needs, and the desired height of the wall. Speaking with a structural engineer can help avoid problems down the road and offer insightful advice.
After your design is complete, the site needs to be ready. To do this, the area must be cleared, the required depth must be excavated, and forms that will shape the concrete must be set up. The stability and longevity of the wall depend heavily on the site’s preparation. To ensure that your wall can withstand the pressures caused by the soil it retains, make sure it has a sturdy foundation and enough reinforcement.
The next step involves mixing and pouring the concrete. For the right combination of strength and workability, the right concrete mix must be used. To prevent weak spots, pouring should be done in one continuous motion. Care must be taken during the curing process, which entails maintaining the concrete’s moisture content and temperature to guarantee proper hardening.
Ultimately, your project will be finished with finishing touches like backfilling and drainage solutions. Weep holes or drainage pipes can be installed to stop water buildup behind walls, which over time can cause damage. After the concrete has completely dried, you can finish any landscaping or other construction around the wall and backfill the area with dirt.
- Purpose of retaining walls
- Types of concrete retaining walls
- Homemade concrete retaining wall
- Preparatory stage
- Formwork and pouring mortar
- Waterproofing and arrangement of a drainage system
- Retaining wall made of concrete blocks
- Video on the topic
- Retaining wall and acting forces
- Retaining Wall Reinforcement | Reinforcement of retaining walls
- Retaining wall made of concrete on the site | Site difference | Monolithic solutions
Purpose of retaining walls
Retaining walls are separated into two major classes based on their purpose:
- Decorative. The main purpose of such structures is to give the landscape of a site with a slight slope a more attractive aesthetic appearance.
- Reinforcing. Such walls withstand significant soil pressure and are designed to prevent it from sliding down the slope and washing out the fertile layer from the surface of the site.
To guarantee stability and longevity, building a monolithic retaining wall out of concrete requires a methodical and meticulous approach. Plan and design the wall first, taking into account the site’s unique requirements. To shape the wall, excavate the area and install a strong formwork. To prevent weak joints, mix high-quality concrete and pour it into the formwork in a single, continuous operation. For extra strength, use steel rebar to reinforce the wall. Before removing the formwork, give the concrete enough time to cure. You can construct a sturdy and long-lasting retaining wall by following these instructions.
Types of concrete retaining walls
There are three varieties of monolithic reinforced concrete strengthening retaining walls:
- massive;
- combined;
- thin-walled.
The first type of retaining walls can sustain soil pressure only because of their bulk (the depth of the embedment also affects strength). These walls require a lot of building materials to make, so when built individually, they can be suggested for low retaining structure construction (0.5 ÷ 0.7 m above ground level) on sites with a small inclination. The thickness (¼ ÷ ½ of the height) should be 0.25 ÷ 0.35 m, and the recommended depth (⅓ of the height) should be 0.17 ÷ 0.24 m.
Products that are combined weigh less than those that are massive. A wider foundation is used than the base of the wall itself in order to increase stability (soil pressing on the protruding elements of the foundation partially reduces the load and increases stability).
Concrete retaining walls with thin walls are formed in an L or T shape. Because these products’ "soles" are wide in proportion to their height, the vertical pressure of the soil on the support greatly lowers horizontal loads and strengthens the wall’s resistance to overturning.
These goods are available for purchase as factory-made, ready-made sections.
Homemade concrete retaining wall
Construction of a concrete retaining wall by hand will not be too difficult if the site’s surface slope is not too great. For instance, a retaining wall that is 1.2 meters high (above ground level) must be constructed. We advise selecting a corner retaining wall with thin walls and a T-shaped base to conserve building materials (concrete mortar and reinforcement rod). Three primary steps for creating a concrete retaining wall are as follows:
Preparatory stage
We first draft a sketch, a drawing, and a plan for reinforcement.
Then we proceed to earthworks. We mark using pegs and construction cord. We dig a trench of the required width (slightly larger than the width of the support, taking into account the formwork) and depth (taking into account the thickness of the support and the cushion of sand and crushed stone). We store the soil from the trench in a free area (later it will be needed for backfilling on both sides of the wall). We fill the bottom of the trench with sand (layer thickness about 0.2 m) and tamp it (periodically moistening with water). Then we fill in the same layer of crushed stone and also tamp it (with a vibrating plate or manual rammer). We lay geotextile on top of the arranged cushion.
Formwork and pouring mortar
We’re going to make a reinforcing frame now. The "sole" and "body" of the wall’s reinforcing bars need to be attached to one another.
We construct the framework. Initially, we only build it for the wall’s foundation. Next, we use a vibrator to compact the concrete mortar that has been poured along the entire length of the foundation. We install the formwork for the supporting wall itself once the solution has solidified. The materials and technology used in the production of formwork are comparable to how a strip foundation is laid up.
Crucial! To drain groundwater and precipitation that seeps into the soil, transverse plastic or asbestos-cement pipes must be laid into the formwork during the arrangement process (the lower edge of the pipes should be slightly above ground level on the outside of the retaining wall). As a result, the load on the vertical slab’s inner side will be greatly decreased. The transverse drainage pipes are separated by 1.0 to 1.5 meters.
After that, we start pouring the retaining wall’s concrete.
Take note! It is best to do this process in stages to avoid the formwork collapsing or deforming during the pouring process. First, fill the wall from top to bottom with the solution up to ⅓ of its height. Next, the solution is poured and vibrated. Fill in the formwork by adding another third of the solution, and so forth.
It is best to fill the entire structure in a single day for maximum strength and uniformity. The surface is leveled, covered with polyethylene film, and allowed to dry completely after the solution has been poured to the top edge of the wall and fully compacted. In hot weather, the surface of the solution is periodically moistened to prevent the rapid evaporation of water, which can negatively affect the strength.
Waterproofing and arrangement of a drainage system
Seven to nine days later, we start removing the formwork. The wall’s concrete surfaces are coated with a waterproofing substance (such as a unique mixture based on liquid rubber) to guarantee durability.
The next step involves setting up a concrete retaining wall drainage system using the subsequent technology:
- Along the entire length of the wall on the inside (that is, on the slope side), we lay a perforated pipe (necessarily wrapped in permeable geotextile).
- Then we fill this pipe with crushed stone.
- We lay geotextiles on top of the crushed stone (to maintain free space not filled with soil between individual particles of crushed stone).
- We take the free end of the pipe (on one or both sides of the wall) into a drainage ditch (or well) or the nearest catch basin.
In the last phase, add soil to the empty space surrounding the wall.
Crucial! Backfilling the soil doesn’t start until the concrete retaining wall reaches its ultimate strength and is able to support heavy loads from the slope, which shouldn’t happen before a month.
The constructed retaining wall’s visible portion is then decorated. Faceting tiles, either real or artificial stone, are typically used for these purposes.
Retaining wall made of concrete blocks
Decorative retaining walls can be successfully built with lightweight porous concrete blocks. Concrete block reinforcement retaining walls are constructed from FBS (solid foundation blocks), which have a minimum width of 400 mm. This value also determines the wall’s thickness. They are produced in factories. The material’s high density (2000–2300 kg/m3) and strength allow for a wide range of applications in the building of large retaining walls.
The following algorithm builds a retaining wall out of concrete blocks:
- We carry out marking, excavation work and arrangement of a cushion of sand and crushed stone (all works are similar to the construction of a reinforced concrete wall).
- After this, we proceed to laying the blocks, which we fasten together with sand-cement mortar.
- We lay the rows of blocks "staggered" (that is, we arrange each subsequent row with a shift of half a block in relation to the previous one).
- To increase the bearing capacity and strength of the wall, we lay reinforcing elements (metal mesh or reinforcement rods) in horizontal mortar joints.
Take note! A standard block measuring 800 x 400 x 580 mm weighs 470 kg. As a result, lifting equipment will be needed to arrange a retaining wall made of these products.
Step | Description |
1. Plan | Design the wall, determine dimensions, and get necessary permits. |
2. Excavate | Dig a trench for the foundation, ensuring it"s below the frost line. |
3. Set Forms | Build sturdy wooden forms to shape the wall. |
4. Reinforce | Place rebar within the forms to add strength to the wall. |
5. Mix Concrete | Prepare the concrete mix according to the manufacturer"s instructions. |
6. Pour Concrete | Pour the concrete into the forms evenly, ensuring no air pockets. |
7. Cure | Let the concrete cure properly, keeping it moist to prevent cracking. |
8. Remove Forms | Carefully take down the forms after the concrete has fully set. |
9. Finish | Smooth out the surface and apply any desired finishes. |
10. Backfill | Fill in the excavated area around the wall with soil or gravel. |
Constructing a concrete monolithic retaining wall is a satisfying project that improves your landscape’s stability and beauty. Building a sturdy and dependable structure can be achieved by following the correct procedures, from preparation and excavation to reinforcing and pouring. To guarantee the longevity and integrity of the wall, each stage of the procedure is essential.
The secret is to prepare. Begin by carefully planning the design of your wall and performing a comprehensive assessment of your site. Precise measurements and appropriate excavation establish the foundation for a prosperous construction. It’s important to install sufficient drainage systems to avoid water accumulation, which could jeopardize the stability of the wall.
Your retaining wall’s strength depends on reinforcement. Rebar positioned correctly guarantees that the wall can sustain the forces applied by the soil. This step affects the overall durability of the wall, so take your time. Before moving on to the next phase, make sure that all reinforcements are properly positioned and secured.
When the concrete is poured, the form of your wall starts to take shape. To guarantee an even distribution of the mixture and prevent air pockets, proceed with a steady and fluid stroke. To achieve a smooth and even surface, finish and compact the concrete using the proper tools. Concrete will be strongest and last longer if it is allowed to cure properly.
Finally, be proud of the retaining wall you’ve completed. It will remain in superb condition for many years to come with routine maintenance, such as checking for cracks and controlling drainage. Building a monolithic concrete retaining wall will benefit your property with a sturdy and long-lasting addition that serves practical and decorative purposes.