Time t/s
Energy E/(N m)
Fig. 12.28 Energy and time curves of descending stages at different return pipe lengths
1À Àd p ¼ 150 mm; L ¼ 100 m; 2À Àd p ¼ 150 mm; L ¼ 50 m; 3À Àd p ¼ 150 mm; L ¼ 20 m
Time t/s
Energy E/(N m)
Fig. 12.29 Hammer strike energy and time curve in descending stage 1—With low-pressure
accumulator; 2—Without low-pressure accumulator
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12 Pneumatic–Hydraulic Pile Driving Hammer