Pile body drilling device capable of preventing hole collapse and construction method

The invention relates to the technical field of pile foundation construction, in particular to a pile body drilling device capable of preventing hole collapse and a construction method.The pile body drilling device comprises a drill rod device and a double-layer cylindrical structure formed by an inner-layer drill rod and an outer-layer drill rod, and a first drill bit is arranged at the bottom end of the inner-layer drill rod; the anti-sloughing hole and reducing structure is provided with a slurry storage barrel and a plurality of slurry conveying pipes, the slurry storage barrel is located in the hollow portion between the inner-layer drill rod and the outer-layer drill rod, one end of each slurry conveying pipe is connected with the slurry storage barrel, the other end of each slurry conveying pipe is converted into a horizontal state by additionally arranging a bent pipe, a grouting pipe is arranged at the end of each slurry conveying pipe, and the horizontal section of each slurry conveying pipe is tele