A high water table poses unique challenges for construction projects. Fortunately, retaining walls can help – especially when they use precast lagging panels.
The water table is an underground line between the surface and the point where groundwater saturates fractures and pores in the ground. This boundary is higher in some places than others, and if your building site has a high water table level, you could face soil stability-related problems.
Though a retaining wall can help you keep this situation under control, you’ll need to create a wall that’s capable of dealing with your local water table level. Waterproofed precast lagging panels are an excellent choice for this use case – in this article, you’ll learn all about the benefits these panels deliver.
The Challenges High Water Tables Present
An area’s water table level can change over the course of the year. In many regions of the United States, water tables rise during the spring months – a situation caused by melting snow in northern states and higher levels of rainfall in the south.
But whether your local water table level is high year-round or only during certain seasons, you’ll have to take those conditions into account while planning excavation and construction work. High water tables can negatively affect soil stability, potentially putting your workers’ safety at risk. As if that wasn’t enough, unstable ground could cause problems for any structures you build on these surfaces.
Determining Your Construction Site’s Water Table Level
Considering risks like these, you’ll need to have a plan in place for dealing with high water tables. Before you do anything else, it’s important to know exactly how high the water table is where you plan to build.
According to the U.S. Geological Survey (USGS), the most accurate way to find the depth to the water table at your job site is to measure it yourself. To do that, you’ll need to locate a shallow well and use tape to gauge its water level.
Unfortunately, your work site might not have a well you can use for this purpose. In that case, you could use surface-based methods such as placing acoustic or electric probes. Databases like the USGS National Water Dashboard can also be useful, but the data they include may be outdated.
How Can Precast Lagging Panels Help?
A soldier pile and lagging wall can be extremely helpful for stabilizing soil conditions on a construction site. Not all retaining walls are built with materials that can effectively deal with high water table levels, but that won’t be something you need to worry about if you use precast lagging panels for this project.
Precast concrete panels are an excellent choice for these walls due to their:
Moisture Resistance
On its own, concrete is a porous material, meaning it can easily absorb moisture. When that happens, concrete will begin to deteriorate and its steel reinforcement will corrode, reducing the structural integrity of these materials.
With that in mind, you might assume that concrete isn’t the best choice for retaining walls that have to deal with high water table levels. But if you choose a trustworthy supplier for precast concrete panels, they’ll be able to waterproof these components for you.
Once waterproofing is in place, your concrete panels will have a much lower risk of developing water-related damage. That makes waterproofed concrete panels an excellent choice for retaining walls in areas where moisture is a concern.
Reduced Risk of Settlement
While working on construction projects, you’ll need to consider your risk of settlement – that is, the downward movement of a structure’s foundation. This situation is closely related to the soil that structures are built on, and saturated soil from a high water table level can greatly increase this possibility.
Compared to other lagging panel materials, precast concrete offers greater stability. Because of that, you’ll be less likely to run into settlement when you build retaining walls with concrete lagging panels.
Why Precast Panels Are a Better Choice Than Timber in These Conditions
While timber is another widely used material for lagging panels, it isn’t as effective as precast concrete – especially when groundwater is a concern. Compared to timber lagging panels, precast concrete delivers:
Less Vulnerability to Water
Timber is a poor choice for retaining walls in environments with high moisture levels. When lagging panels made from wood get wet, they can easily warp and swell – and at that point, you’ll need to replace these components.
On the other hand, waterproofed concrete panels will have no trouble withstanding groundwater and precipitation. That alone would be enough of a reason to choose precast concrete over timber for your lagging panels, but the benefits don’t stop there.
Lower Maintenance Requirements
When you build a retaining wall with timber lagging panels, you’ll need to put serious work into maintaining this structure. This process involves checking your panels for problems like decay and damage as often as once a month.
Though you’ll also need to inspect precast concrete lagging panels for signs of trouble, you can wait much longer between inspections with these components. Precast concrete panels only need this type of attention once a year (or even once every other year).
A Longer Lifespan
Even if your timber lagging panels don’t run into catastrophic problems, you’ll still need to keep the lifespan of these panels in mind. Treated timber panels can stay in place for decades, but precast concrete can last even longer.
In fact, the National Precast Concrete Association has stated that precast concrete has a lifespan of 50-100 years on average. Thanks to this long-term durability, concrete lagging panels are a much smarter pick than timber for any permanent retaining wall project.
The Importance of Drainage in Retaining Walls
While precast concrete lagging panels are a fantastic choice for retaining walls, you’ll need to watch out for potential issues with these structures, including hydrostatic pressure. When the soil held back by these walls absorbs water, hydrostatic pressure will increase. Eventually, that buildup of pressure could damage (or even destroy) your retaining wall.
Hydrostatic pressure can be a problem for retaining walls anywhere, but it’s an even bigger issue in places with high water tables. The best way to avoid pressure-related trouble is to give groundwater a chance to escape. To make that happen, you’ll need to include a drainage system in your retaining wall design.
Some drainage-related features that can improve retaining walls include:
- Weep holes. If you include these holes in a retaining wall, water will be able to get out before hydrostatic pressure reaches dangerous levels.
- Geocomposite drains. Geocomposite drains are multi-layered, sophisticated drain products that help water flow as quickly as possible.
- Chimney drains. These drains are vertical columns made of free-draining material that move water away from specific areas.
- Outlet protection. While it isn’t a type of drain, outlet protection is definitely worth including on your retaining wall. This can reduce water flow and protect the ground near drains, helping keep water erosion under control.
Get Top-Notch Waterproofed Precast Lagging Panel Walls
If you plan to build in an area with a high water table level, you’ll want retaining wall systems made from high-quality, waterproof precast lagging wall panels to help prevent costly water damage. That’s exactly what you’ll get from American Precast Concrete Inc. We provide expert installation support and sell the industry’s best lagging panels, with customizable solutions to meet your exact needs. Contact us today if you’re ready to take the first step!