Have you ever passed by something like the picture above and thought, “What is that for?”

It is a top-to-bottom retaining system called soil nailing and is used to prevent landslides and the earth from collapsing or shifting. Creating a soil nail wall is ideally used in situations where vertical excavation needs to take place. This process is used to construct tunnels, bridges, roadways, and areas where retention walls have failed or are beginning to fail. The process starts with a downward angled hole being bored out of the existing slope. Then a long, steel reinforcement tendon (or rebar) is inserted into the bored or angled soil. The steel tendons are then cemented into place with a grout mixture to stabilize the soil and prevent it from moving or falling. After all the nails are cemented into place, then a permanent concrete facing can be built.    

Soil nailing has multiple advantages over just stand-alone ground anchors and other top-down construction techniques. Here are just a few of the benefits described below:

  • They are less obstructive in traffic situations since there is no need for braced excavations.
  • Installation is relatively quick and requires fewer construction materials than using ground anchors.
  • The nails’ placement, inclination, and lengths can be altered easily when heavy rock or utility lines are in the way.
  • The soil nailing system offers excellent flexibility in the ground and generally performs well during earthquakes.
  • Using a soil nail system is oftentimes more cost-effective than concrete gravity walls and ground anchor walls

If there’s one thing working here at D.L Howell & Associates has taught me, it’s that there’s always more to learn!