Ultra-long spiral drilling machine drill bit suitable for mud flat area

The utility model discloses an ultra-long spiral drilling machine drill bit suitable for a mud flat area, and aims to solve the problem that an existing spiral drilling machine drill bit cannot adapt to the complex geological environment of the mud flat area and the power supply of an ultra-long spiral drilling machine. The device comprises a hollow pipe and a spiral cutter head arranged on the outer surface of the hollow pipe, a flange plate is arranged at one end of the hollow pipe, and a blocking door is hinged to the other end of the hollow pipe; the spiral cutterhead is of a double-spiral structure and comprises a long spiral cutterhead starting and ending at the door blocking end and the flange end of the hollow pipe and a short spiral cutterhead with the starting end line collinear with the starting end line of the long spiral cutterhead. A limiting plate is vertically arranged on the blocking door, and a limiting groove corresponding to the limiting plate is formed in the hollow tube; the horizontal c