| 摘要 |
<p>The invention relates to a pile installation frame (30) comprising one or more tubular noise reduction elements (1, 31,32,33) having a cylindrical wall (2)and a center line (8). The elements (1, 31,32,33) are along their length provided with spaced-apart positioning devices (12,13,14) that are radially retractable with respect to the centerline, for centering a pile (7) driven through the tubular element (1, 31,32,33) along the center line (8). The positioning devices are retracted when the hammer passes downward into the space bounded by the cylindrical wall.</p> |
