Self drilling anchors are often used in various anchoring projects to anchor and support the surrounding rock formations, but the construction environment is different for each project. Selection of the drilling method depends on the number of self drilling rock anchors, the composition of the soil or rock, availability of equipment and the required diameter of the hole. The selection of the tools and techniques should be left to the discretion of the drilling contractor where practical. The depth of the bore hole should be based on sit tests. The diameter of the bore hole should exceed the maximum diameter of the anchor by at least. If centering devices are used, larger holes are required. The choice of the drill bit is selected according to the geological conditions. The soft soil layer can be drilled with a clay drill bit, a hard soil layer or a broken rock layer can be drilled with a more strong drill bit. The length of the hollow anchor bar can be freely intercepted and extended. The choice of grouting material should be selected according to geological conditions and engineering budget.
