Technological principle Using the rotary device of the JAR full casing full rotary drill, the friction resistance between the steel casing and the soil layer is greatly reduced, and the rotary side is pressed in, while the impact grab bucket and the impact hammer are used to dig the soil until the casing reaches the bearing layer of the pile end. After the excavation is completed, the depth of the excavation is determined immediately, and the bearing layer of the pile end is confirmed, and then the empty soil is removed. After the hole is formed, the steel cage is put in, and then the pipe is erected in the center of the hole, and finally the concrete is poured into the pile.