Abstract: A shield tunneling machine comprises a tubular shield body, a partition wall provided in the shield body, a rotary shaft supported rotatably by the partition wall and extending longitudinally of the shield body, a cutter head disposed on the front end of the rotary shaft and a mechanism for rotating the cutter head through the rotary shaft. The cutter head comprises a first cutter provided with a plurality of cutter bits and a second cutter provided with a plurality of roller bits. The machine also comprises a mechanism for moving straight forward and backward one of the first and second cutters relative to the other. The machine locates the first cutter more forward than the second cutter for excavating the face of stratum having a soft layer like clay layer with the first cutter and the second cutter more forward than the first cutter for excavating the face of the stratum having a hard layer like bedrock layer with the second cutter.

Abstract: Method for thrusting a shield for use in tunneling includes the steps of causing a rotary head, provided at the front portion of a shield body, an eccentric motion so that earth, soil or sand covering the front of the shield is pressed away radially of the shield, and exerting a thrust on the shield body during the eccentric motion of said rotary head. Apparatus for carrying out the method includes a driven crank shaft or a driven eccentric straight shaft, a conical or frustoconical rotary head supported rotatably by the crank or eccentric straight shaft, conveyor for discharging mined material backwardly, and hydraulic jacks for imparting a thrust to the shield body.

Abstract: A method for excavating a tunnel wherein the muck from the tunnel face is admitted into the shield; the muck is pressed by a pressure of a predetermined level higher than an active earth pressure in the face and lower than a passive earth pressure as the shield body is moved forward, thereby establishing the balance between the earth pressure in the face ground and the muck pressure; and a liquid of a level balancing the underground water pressure is used to resist the underground water, thereby preventing movement of the underground water, whereby the face is maintained stable; and when the muck pressure is raised over the predetermined level, the muck is discharged out of the shield.

Abstract: A pipe jacking apparatus comprises a shield type tunneling machine equipped with direction adjusting jacks, a tubular body joined to the rear of the shield type tunneling machine, and a thrust jack provided within a thrust pit and thrusting forward a pipe member placed between the shield tunneling machine and the thrust jack, in cooperation with the shield type tunneling machine. The aforesaid tubular body includes a panel therein having output gages for the aforesaid jacks and a mark representing the center of the tubular body, and a TV camera for taking a picture of the panel. This TV camera is connected to a TV receiver provided in a remote control unit. In the aforesaid pit, there is provided an optical unit having a line of collimation directed to a predetermined direction to thrust a pipe, or a light source for light beams.

Abstract: In a shield-type tunneling machine, a pair of comb-type bit-plates are pivotally supported on a peripheral wall of each cutter slit provided in a cutter disc. In order to adjust a degree of opening of each slit as well as a cutting angle of the bits with respect to the facing, the bit plates are pivotally moved to an open position or a close position for opening or closing each slit, in association with the reciprocating motion of a slide shaft disposed in a hollow drive shaft which rotates the cutter disc.