Full pile casing twisting follow-up rotary excavating pore-forming construction method

The invention discloses a full pile casing twisting follow-up rotary excavating pore-forming construction method. The construction method is characterized in that a pipe twisting device and a matchedsteel casing are adopted, a single-casing method or a double-casing method is selected according to the needed casing depth, wherein according to the single-casing method, the casing is installed after a pile hole is positioned, core drilling is conducted through a rotary drilling rig, the casing is pressed downwards and screwed into a soil layer through the pipe twisting device every time a certain depth is drilled, and the cycle is repeated till the casing is embedded into bedrock or reaches the designed depth; and according to the double-casing method, in order to overcome the frictional resistance of a soil body to the pile casing, a pile casing construction sequence from outside to inside is adopted, other operations are the same as those of the single-casing method, and a multi-casing method can be derived i