Variable-angle autorotation type rotary excavating drill bit and foundation construction method thereof applied to root pile

The invention discloses a variable-angle autorotation type rotary excavating drill bit and a foundation construction method thereof applied to a root pile, and belongs to the technical field of root pile drill bits. The variable-angle autorotation type rotary excavating drill bit structure comprises a shell and a rotating shaft, a plurality of drill bit mounting shafts annularly arranged on the outer side of the rotating shaft are arranged on the shell in a penetrating mode, detachable drill bits are mounted at the bottoms of the rotating shaft and the drill bit mounting shafts, the rotating shaft is located on the outer wall of the shell and connected with a driving gear in a sleeving mode, driven gears sleeve the outer walls of the drill bit rotating shafts through a floating structure, and an adjusting structure is arranged at the top ends of the drill bit rotating shafts. According to the novel rotary excavating drill bit, through a single-shaft transmission principle, self-rotating root pile drilling equ