The upper and lower cages on the construction site that block the conduits are called steel cages. The main function of the steel cage is the same as that of the longitudinal steel bars of the column. It mainly plays a tensile role. The compressive strength of concrete is high but the tensile strength is very low. It restrains the concrete of the pile body so that it can withstand a certain axial tension. During the construction of bridges, culverts or high-rise buildings, foundation piling may be required according to requirements. The method is to use machine punching and water mill drilling.