Designing a backyard retaining wall for home improvement becomes challenging sometimes, and when the owner is unable to build one for this landscape, he needs to hire an engineer. Retaining walls can help an owner in multiple ways. For example, during heavy rain, the soils get washed away because of the raindrop impact, but a retaining wall can trap those soil particles and pass the water. These structures are crucial in hilly regions because they can minimize soil erosion to a larger extent.
In this article, we will help those homeowners who want to build a retaining wall for home improvement. Here, we will disclose the basic principle and considerations to design a wall.
Considerations for backyard retaining wall designing
There are four things needed to be investigated to design the structure –
- What is the stability of the soil?
- What is the stability of the structure?
- What is the structural strength of your structure?
- Are there any possible damages close to the wall during construction?
While thinking about the lateral ground/earth pressure, remember that it depends on the movement of the vertical wall. There are three categories of earth pressure that act upon the structures – i) active, ii) passive, and ii) at rest pressure.
At rest pressure takes place when the structure doesn’t show any lateral movement. Active pressure develops when your retaining wall will be free to move, and it is related to the shear strength. Passive pressure takes place when the ground is compressed, and the wall moves into the soil.
Therefore, the basic pressure for designing a retaining structure will be –
Normal load = Sum of static earth load, water pressure, and live loads/surcharge pressure. Remember that the design pressure for the wall shouldn’t be less than the load/pressure provided by the fluid (that has the unit weight of 5kN per cubic meter).
Sometimes more surcharges are needed to consider because the owners may need to deal with the structure and its adjacent place in the future. During the excavation process, the owner also needs to focus on the bearing strength of the soil.
Choosing the materials for backfilling is necessary because these materials exert pressure on the walls, and for this, free draining and granular materials with a higher shear strength are preferred. Indeed, you will need to think about the affordability and price rate while buying the materials.
For example, when you choose heavy soils like clays for backfilling, it will not be a good choice for that. Clay particles have swelling and shrinking characteristics, and when these particles absorb moisture during the rainy season, they will swell and shrink upon drying. These swelling and shrinking characteristics will exert pressure on the wall, and you may face long-term problems. However, these problems can be overcome by using sand or silt materials that are cohesionless. It needs to be mentioned that silt particles can get washed away quickly. So, the best choice is undoubtedly sand materials.
The last thing that needs your focus is – drainage. Make sure that the materials drain the water effectively, and it will reduce the water pressure. In this case, the engineers suggest using the rockfills or decomposed volcanic rocks.
These are the major considerations while designing a retaining wall for home improvement.