The present invention provides an excavation device with a limit protection function and a square hole excavation method thereof, which are applicable to the field of
engineering construction. The excavation device of the present invention includes a control
cantilever, an eccentric rotating shaft, a spiral
drill bit and a limit protection device, wherein the limit protection device includes a limit frame and a card plate, wherein the limit frame has an annular groove for accommodating the outer periphery of the card plate, the upper end of the limit frame is fixedly connected to the control
cantilever, and the eccentric rotating shaft is connected directly below the control
cantilever. The lower end of the connecting shaft of the eccentric rotating shaft is connected to the driving gear through the driving shaft through the
cam assembly, and the driven shaft of the eccentric rotating shaft passes through the center of the card plate and is connected to the spiral
drill bit. The present invention solves the problem that the horizontal lateral force of the
drill bit of the excavation equipment increases suddenly, causing the
cam assembly and the gear connection to be easily damaged. When the spiral
drill bit encounters inclined rocks or hard objects, the limit protection device can provide a certain horizontal lateral force constraint. When it is detected that the horizontal side pressure exceeds a certain threshold, an automatic alarm is issued to prompt the on-site personnel to stop the excavation work.