| 摘要 |
<p>A sheet of material is laid in the ground by digging a trench in the ground by means of a trench digger and unwinding the sheet of material from a stock roll above ground level, passing it into the trench in a downward direction and diverting it in a direction essentially parallel to ground level. In order for the protective housing which is attached downstream of the trench digger and has to keep the trench open over its length not to be designed too long the sheet of material is passed, folded twice, in the trench and is passed further via three return rollers or rods or flanges, in the unfolded state in an approximately vertical plane in the horizontal direction. To lay the film at a particular depth in an approximately horizontal position or in the shape of an essentially horizontal gutter in the ground the sheet of material is passed, folded twice, in a trench in the shape of an inverted T and, via four return rollers or rods or flanges which are located essentially near the bottom of the trench, is folded open and passed further in a horizontal or gutter-shaped position in the horizontal direction.</p> |
