| 摘要 |
PURPOSE:To measure a distance accurately without being affected by underground water by measuring the press-in quantity of a buried pipe by means of a band plate, by a clamp fixing one end of the band plate on a buried pipe, a traction means which pulls the other end of the band plate at a starting shaft front section, and of a laser irradiation range finder. CONSTITUTION:A starting pit wall 7 preventing underground water and earth and sand from entering in, is set at the drive position of a buried pipe 11 at a front face within a starting shaft, and a hole larger than the outer diameter of the buried pipe 11 is bored at the center section of the starting pit wall 7. In this case, a water stop rubber 18 is installed in the hole section while being brought into contact with the outer circumference of the buried pipe 11. Furthermore, a push ring 8 is set at the rear end of the buried pipe 11, so that the propelling force of main thrust jacks 12 mounted on their rear section is thereby uniformly transmitted to the buried pipe 11. Beside, a bearing wall 13 is provided for the rear section of the main thrust jacks 12 for supporting the propelling force. Since the band plate 2 is moved forward by a traction means by the press-in quantity of the buried pipe 11 as the buried pipe is thrusted, the quantity of the movement of the band plate can thereby the measured by a range finder 1. |
