SEMI-SHIELD MACHINE

PURPOSE:To discharge a cut soil inclusive of huge rocks so smoothly by installing a cutter driving rotary cylindrical body concentrically in a shield inner part, while setting this inner part down to a cut-soil discharging passage. CONSTITUTION:This semi-shield machine is provided with a large diameter cylindrical body 21 consisting of a funnelform part 21a with a holding member 20a for a cutter 20 and a right cylindrical part 21b extending rearward. Next, each cylinder 21 is concentrically installed in both front and rear shields 10 and 11 via a bearing 35. Then a rotational driving means 30 consisting of plural hydraulic motors 31 and so on is installed in space between the shield 10 and the cylinder 21, rotating this cylinder 21. Further there is provided a superplasticizer charging means 40, through which a superplasticizer is delivered up to the vicinity of the cutter 20 via a channel fitting 44. Then the cutter 20 is rotated, while a rear end of the shield is pressed via a Hume pipe 3, and excavating operation takes place as discharging a cut soil from the cylinder 21. With this constitution, the cut soil is smoothly discahrgeable, thus a small diameter shaft can be easily excavated into huge rock ground.