| 摘要 |
<p>for thrusting a shield for use in tunneling includes the steps of causing a rotary head (14), provided at the front portion of a shield body (12), an eccentric motion sothat 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 outthe method includes a driven crank shaft (22) or a driven eccentric straight shaft, a conical or frustoconical rotary head (14) 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 bodv.</p> |
