| 摘要 |
PURPOSE:To precisely compensate the position of an excavator by setting positional shift adjusting values with respect to a planned line, at predetermined intervals during a pilot head is pushed, and compensating the positional shift when it exceeds the such a value after the excavation is made by a predetermined distance. CONSTITUTION:A pilot pipe 6 is connected to a pilot head 4 having a cutter and is pushed by a propulsion jack 5. A positional shift of the head 4 with respect to a planned line is measured with the use of a laser or the like, and excavation is carried out while the positional shift is corrected. During excavation, positional shift adjusting values with respect to the planned line are set at predetermined intervals in accordance with a predetermined expression formula. Whether or not the positional shift after excavation by a predetermined distance is below the associated positional shift adjusting value is determined. If it exceeds the value, it is determined that the position of the measuring unit such as the laser or the like is deflected, and a true shift value is corrected in accordance with a difference between the measured positional shift value and the positional shift value, and is displayed. Accordingly, it is possible to prevent a buried pipe or the like from being largely shift from the planned line. |
