A steel pipe 1 used for the in- situ casting of concrete piles is withdrawn from the ground after casting by means of wires 9 fastened to the ends of steel springs 10 of which the other ends are fastened to a traction bushing 11 which is fixed to the pipe 2. During withdrawal of the pipe, a cap 4 on the end of the pipe is struck repeatedly by a drop hammer 5 in a succession of short strokes. The combination of the action of the drop hammer 5 and the springs 10 causes the tube 2 to vibrate and thus facilitates the lifting action. The drop hammer 5 is operated by a lifting cylinder 7 fixed to a frame 6 which is raised progressively as the tube 2 is lifted, by the provision of a recess 12 into which the cap 4 fits. This enables the same drop hammer to be used both for driving the pipe into the earth initially and for subsequently producing vibration during withdrawal, thus obviating the need for separate vibration equipment. IMAGE
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