| 摘要 |
PURPOSE: To obtain an arcuate thrust apparatus that advances along a predetermined track by rendering an inner and outer pipe pliable in its joint parts, and measuring the deflection of a target and the distortional angle of the outer pipe to thereby control the direction of a movable shoe. CONSTITUTION: An inner pipe 30 with a bit fastened at its distal end and an outer pipe 20 including a leading pipe 10 provided with a movable shoe 16 are rendered pliable in respective joint parts 32 and 40. On the other hand, a bore center measuring device 50 is set within the outer pipe 20 in order to measure the deflection of a target and the distortional angle before being displayed on an operational stand of the apparatus. By the value, a direction of the movable shoe 16 is controlled through the operation of a directional correction cylinder 14, so that its advancing operation can be performed along a predetermined track. As such, an excavation of small radius of curvature becomes possible in sharp curves, and construction costs can be reduced greatly. |
