| 摘要 |
PURPOSE:To prevent a synthetic resin pack from damage and to improve its working efficiency by incorporating a sensing medium to be detected by the five senses and a shape holding medium in an airtight room of said pack and previously detecting the presence of a tube body. CONSTITUTION:A tube body 6 is embedded in the ground 7 and the synthetic resin pack 1 is embedded around the tube body 6. Drilling work such as boring is executed by pushing a drill 8 into the ground 7 together with mining water. At that time, the top of the drill is abutted upon the pack 1 at first before collision with the tube body 6. Consequently. the pack is broken and the sensing medium 4 and the shape holding medium 5 which are incorporated in the airtight room 2 are sprung out from the airtight room 2. At the periphery of the drill 8, a apace 10 is formed in addition to water. If the medium 4 is liquid or granular, the medium 4 is mixed with the mining water and raised up to the surface of the ground. Thus, the existence of the tube body 6 is detected by checking its color change. In addition to the visual detection, the presence can be detected by the sense of smell or the like through the space 10. |
