The casing is a thick steel tube. The casing used extensively in construction drilled piles. The casing used to guide the drilling rig to drill the pile hole in the correct location. Also, it can be used to stabilize and prevent the soil from collapse until the concreting of the pile is completed.
Furthermore, the casing will be used to hang the steel cage until the concrete is poured. The used casing should be thick and strong enough to resist the imposed stresses during the installation and removal process for temporarily casing. The casing should be clean, smooth, free from encrusted concrete, or any damage that can affect the size and shape of the pile.
The casing length will vary according to the purpose of use and the type of the soil. If supporting fluids are used to stabilize the soil, the casing will be used as a guide for the drilling rig.
Therefore, the casing length will be short. If the casing is used to support the soil, the casing length should be sufficient to reach the rock and hard layers of soil.
Pile casing can be permanent or temporary.
The permanent casing will not be extracted after the casting of concrete. While the temporary casing will be extracted after the casting of concrete. The temporary casing should be removed while the concrete is workable.
The early removal of casing will prevent the casing from damaging the pile concrete. Also, it will prevent the casing from stuck to pile concrete. Usually, the Vibro hammer is used to install and remove the casing.