The soil within the wall absorbs water from rainfall and groundwater, among other sources. A drainage system consisting of perforated pipes, filter fabric, and drainage stone drains the water and keeps the wall intact. This type of drainage system is necessary for retaining walls under the following circumstances:.
Perforated pipe systems have slots on each pipe that allow the water to drain from the soil into the pipe. Then the water flows through the pipe to an outlet in or near the wall.
Once the water reaches the pipe outlet, it flows away from the wall. Overall, the pipe connects to outlets that carry the water away from the soil behind the wall as safely as possible.
Whether you are planning to install your own retaining wall or have someone else do it, understanding how drainage should work will ensure the best possible end result. A retaining wall is built to hold back a certain amount of soil. The design of a properly-built retaining wall resists the force of the soil behind it and prevents caving, buckling, or leaning.
However, retaining walls are built with a certain capacity in mind. When the wall is no longer able to resist the force behind it, the weakest part will give.
Sometimes, this means that the wall will develop a bulge at this weak spot. In other cases, water pressure behind the wall may cause it to lean outward. If the pressure is consistent and forceful enough across the wall, it may even buckle. The process of making sure that a retaining wall drains properly is relatively simple, but it is not very flexible. Although there are exceptions, most retaining walls require gravel backfill, soil compaction, pipe or toe drains, and weep holes.
Together, these four features will provide adequate drainage for most designs. Only a few types of walls will not require all of them. Convention says to add at least 12 inches of gravel backfill, but Christofora's motto here: The more the better. For existing walls, you may want to excavate to see if the gravel is at that inch minimum. If needed, you could dig down far enough to see if there is the necessary footing drain and gravel under the wall as well.
Just be careful not to undermine the wall. Although it might seem counterintuitive, use a compactor on the soil behind your completed retaining wall, after adding your plus inches of drainage gravel.
Water-saturated soil can cause tremendous hydrostatic pressure to be exerted on your retaining wall. Compacting the soil makes it less permeable, sparing your wall of potential and potentially damaging water weight. If hand-tamping, lay a 1- to 2-in. If using a gas-powered tamper , you can lay up to six inches of soil between tamps. Filter fabric, AKA geotextile underlayment fabric , is a permeable fabric commonly used as a filter between soil and gravel surfaces.
It keeps dirt and debris from clogging the gravel, and therefore preserves retaining wall construction. Christofora recommends using it at every place where soil and gravel meet, including under the wall's gravel footing, between the footing drain's gravel and soil and under the gravel added behind the retaining wall.
Weep holes are small, evenly-spaced holes along the bottom section of your wall. They protect the structural integrity by allowing underground water to seep through, preventing pressure build-up. Every retaining wall should have them. And yes, you can add them retroactively — drill them into an existing concrete, stone or brick wall using a core drill and drill bit , which you can often rent at your local hardware or DIY home improvement center.
Your wall's scale will determine weep hole size and spacing. For large walls, around 6 ft. Though Christofora notes that these figures can vary depending on wall height as well as soil type , topography and other site conditions. One caveat from Christofora: "Adding weep holes may help save a retaining wall, but if the wall was backfilled with soil, and there's no gravel behind it, you may not get enough drainage through the weep holes.
Even with lots of correctly installed drainage around your retaining wall, if the soil on the other side doesn't slope away sufficiently, that water won't go anywhere.
Any amount of slope will do, provided it doesn't reverse a short distance away. Keep in mind where the water will end up. You don't want the excess water draining onto someone else's land or into a pond, lake or river. Other options, if you're in a pinch: "Build a French drain or a dry well , where water can flow into a gravel trench or pit and then be absorbed into the ground," Christofora says.
Avoid dirtying spoons with this innovative self stirring mug. It quickly blends beverages without the effort of shaking or stirring using two AAA batteries not included. Check out these 14 super cool homemade coffee table ideas. Buy it on Amazon now. Social media has been all over this trending gadget, which will take your home decor to new heights. If you've ever wanted the sweet light of the moon to fill up your room, now it can! The moon lamp offers a relaxing environment to revel in while giving you just one more reason to "space" out.
If you like slightly "out there" products, check out these 10 weird things you didn't know you could buy at Lowe's. Jump on the bandwagon! Place filter fabric at the interface between the back of the block and the pipe to prevent backfill from migrating through the opening. You can also grout around the pipe at the front face of the block. This prevents rodents from getting into your drain pipe and building a nest.
Outlet the pipe underneath the wall. This is ideal when there is a toe slope in front of the wall. This avoids cutting the blocks and allows the pipe to be placed lower on the wall. In this case, extend drainage stone all the way to the bottom of the wall.
This is an innovative product that is not as widely known. Place the Universal Wall Drain vertically between segmental blocks so you avoid the need to cut the blocks. It then connects directly to the tee connector in the perforated drain pipe. The universal wall drain is an aesthetically pleasing option that avoids rough cut marks typical in pipe outlets. It also has a built in grate to keep rodents from crawling into your drain and building a nest.
This outlet option helps reduce labor time and reduce the number of materials needed. Drainage is a critical part of any retaining wall system. It cannot be overstated how important managing water is for the long term performance of your wall. If you have questions about drainage design, or anything else related to your retaining wall project, leave a comment below or hit the email icon at the bottom of the page. I was curious if you ever thought of changing the page layout of your site?
Its very well written; I love what youve got to say. But maybe you could a little more in the way of content so people could connect with it better. Youve got an awful lot of text for only having one or 2 pictures. Skip to content. Below are several scenarios that require a drainage pipe behind the wall: Walls with a height greater or equal to 4-ft as measured from the foundation to the top of the wall.
The segmental blocks cannot hold the weight of that much water by themselves. Also, walls greater than 4-ft can cause catastrophic damage if the wall fails.
0コメント