| 摘要 |
The underground pipe is formed by a number of sections (2,4). These sections are joined at their ends and assembled by direct advancement into the soil. Advancement of the pipe into the soil is facilitated by a lubricant (32) applied to the outer face of the pipe. The lubricant is surrendered to the tube outer face by holes in a seal (24,25,28) located between the ends of the adjacent pipes. |
