CUTTING EDGED EXCAVATION DEVICE

PROBLEM TO BE SOLVED: To provide a cutting edged excavation device capable of reducing a volume of work for ground improvement and preventing the blows of water content in the ground or the collapse to make stable boring. SOLUTION: The edged excavation device having a cutter 1 mounting a plurality of excavation bits 1b on the front end of a cylindrical shell 2 in a ring-shape in a rotatable manner, having a driving means rotating the cutter 1 inside of the shell 2, placing a driving pipe 5 on the rear end of the shell 2 and boring while forming a pipe-line by pushing the driving pipe 5 from the back is so constituted that excavated earth and sand are taken into the shell 2 located backward of the cutter 1 to have an earth-moving pipe 3 for sending the earth and sand out to the back, a valve 4 capable adjusting a discharging amount of the earth and sand is provided to a middle part of the earth-moving pipe 3 and that the pressure of a cutting face can be held in a state to prevent the collapse of the ground by controlling the valve 4.