Retaining wall projects can extend from smaller projects for residential properties to huge construction projects along major roadways and motorways.
Still, everyone knows that whether you have a big project or a small one, several essential factors can affect the resulting wall – and affect its integrity. The soil, for instance, has to be firm and solid, but the area’s inherent drainage pattern can affect the retaining wall’s strength and durability. So you must think carefully about these factors to ensure that your retaining wall is as stable as it can be. But how can soil and drainage impact the integrity and design of your retaining wall, and what can you do to lessen their impact? Here’s what you should know.
The soil: essential considerations
Your retaining wall needs to have a solid foundation, and the soil will, of course, form its foundation. But, first, you would need to have the base examined to ensure that it has enough strength to support the retaining wall. Some foremost considerations include the type of soil and its capacity for bearing weight or supporting a load, its parameters in terms of stress, and its angle of friction or how it resists movement. It is necessary to determine all of this not just for the soil you will use for the wall’s foundation but also for the zone you need to reinforce.
Ideally, the soil for the base should be strong, solid, and firm, and it shouldn’t exhibit too much moisture. Soil with too much clay can be wet, which isn’t ideal for infilling, either. Since the ground is already water-saturated, any extra moisture will not flow through to the drainage outlets or channels. If the area is prone to freezing, moisture-rich soil will likely expand then contract, leading to wall damage.
Alternatively, if the soil is sandy, this could result in better drainage. Again, it’s vital to consult with a geotechnical expert so they can produce a report that has a good description of the soil on-site and its chemical properties, as well as the condition of the groundwater.
The drainage: important considerations
Specialists in concrete retaining wall construction will also advise you to look closely at the drainage for your retaining wall project. Remember that water can cause retaining walls to fail, and water is, in fact, one of the main reasons why retaining walls collapse. But the solution to this is proper drainage, so there is no water buildup along the wall’s perimeter and behind it.
One thing you can do is determine potential sources of surface water and then make sure that you install drainage along the site of the wall. Make it a point to grade the wall site, determine the innate drainage pattern, and build a proper drainage system right behind the retaining wall. It then allows you to minimise the hydrostatic pressure created by the groundwater. Some standard drainage systems include utilising drain pipes, creating a backfill using gravel, and making use of tiny holes (weep holes) so water can easily flow through the retaining wall. A hydrology report and analysis are essential if you are involved in a larger project (like those involving transportation).