Tunnel and underground engineering full cross-section cantilever tunneling machine milling and excavating device and method

The invention discloses a tunnel and underground engineering full cross-section cantilever tunneling machine milling and excavating device and method. The device comprises a machine body. A walking portion is arranged at the bottom of the machine body. The machine body and the walking portion are connected through a rotating mechanism. The lower portion of the front end of the machine body is connected with a shoveling plate through a first air cylinder. The upper end of the front end of the machine body is connected with a cutting portion through a second air cylinder. The front end of the cutting portion is provided with a milling and excavating head. The milling and excavating head is of a hemispherical structure. The two sides of the cutting portion are provided with infrared distancers. An electrical control system is arranged on the machine body. The device is simple in structural principle, capable of effectively limiting compressional deformation and converging deformation of an excavated rock body on an excavating face in front of the excavating face, advanced supporting is not performed on the condition that the surrounding rock level is not poor, the tunnel excavating cost is saved, and the excavating efficiency of the cantilever tunneling machine is improved.