A sheet piling is both a form of retaining wall and the sheets used to make the wall. These sheets are commonly made of metal but may also be vinyl or wood. The sheets are driven into the ground and locked together to form a tight physical barrier to water, insects and plant life. These types of retaining walls are common in areas with loose sand and soil, as they are relatively easy to place and maintain. Small walls are generally two parts below ground and one part above, but larger walls may have a larger underground area or additional supports.
The material used to make a sheet piling varies based on the desired use of the wall. The most common and general purpose material is metal, but certain plastics and wood have uses in specific circumstances. The metal used to make sheet pilings is almost always galvanized steel. This metal has undergone a process to make it more resistant to environmental dangers, such as impacts and moisture.
There are a variety of common sheet piling shapes. Many of the basic styles have alternating high and low flat surfaces connected by sloped sides; much like the corrugation inside cardboard. This shape both improves the metal’s structural stability and makes it easier to stack for storage or transport. With this design, there is typically a break in the middle of the high or low flat spot.
These breaks are what make the sheet pilings so effective. The edge of each piece is specially designed to connect to the edge of the piece next to it. This allows the wall to be of any size or shape as well as follow the contours of the land. By making the break in an open area, rather than a corner or intersection, pieces of different design can work together to make up the larger wall.
Sheet piling retaining walls are used in many different types of construction. In some areas, they are placed underground a small distance away from the foundation of a structure. This helps prevent water from reaching the building’s true foundation. Even so, their most common use is as retaining walls in loose terrain. Since the walls are so thin, it is easy to push them down into the loose ground, and their interlocking plates allow them to work around underground obstructions, such as rocks or utility lines.
In order to maintain stability and keep its shape, a sheet piling needs twice as much underground as above ground. In particularly loose areas, or with larger walls, other measures are sometimes taken. Diagonal supports are the easiest additional support method and are placed on the low side of the wall. In addition, anchor lines are sometime connected to the wall and run diagonally up through the retained material and anchor on the surface.