| 摘要 |
<p>Apparatus for boring holes in the ground is provided, the apparatus comprising two cutting heads (1.1, 1.14) arranged coaxially and separated by an elongate tubular member (1.4). The first cutting head (1.14) is carried by the elongate tubular member itself, and acts as a pilot boring head. The second cutting head (1.1) is annular and serves to form the bore proper. The apparatus also includes means (1.7) carried externally by the elongate tubular member for collecting debris produced in the course of a boring operation, or for deflecting debris away from the first (i.e. lower) cutting head. In one development, the elongate tubular member is cut away in part so that the interior of the tubular member is exposed to part of the earth surface within the pilot bore. The debris collecting means can be in the form of a collar located about the elongate tubular member, or it may be in the form of a helical ledge or scroll (1.7) which carries debris along when the first cutting head is rotated. Embodiments of the apparatus provide a large degree of working space within the elongate tubular member (1.4) which allows the provision of other functional units, such as debris removal means, pumping means, and grouting means, as well as allowing adequate space for inspection of the earth surfaces which are being worked.</p> |
