| 摘要 |
<p>The system inserts open or closed tubular piles in the ground, the pile casing, usually of steel, being driven in by a compressed air or hydraulic hammer mounted inside it. Alternatively, the hammer can be placed on the casing, or it can be inserted in it when in the horizontal position, the driving energy being transmitted directly to the tip. The casing need be no longer than the hammer, and the tube directly above the casing can have a thinner wall or be of different material, e.g. cardboard, or in the form of a woven nylon stocking, filled with a supporting liquid to hold the space formed free.</p> |
