Time t/s
Energy E/(N m)
Fig. 12.26 Influence of diameter of return tubing on strike energy 1À ÀL ¼ 50 m; d p ¼ 50 mm;
2À ÀL ¼ 50 m; d p ¼ 150 mm; 3À ÀL ¼ 50 m; d p ¼ 250 mm
Time t/s
Displacement y/m
Velocity v/(m/s)
Fig. 12.27 Influence of length of return tubing on displacement and velocity in descending stage
v 1 ; y 1 À Àd p ¼ 150 mm; L ¼ 100 m; v 2 ; y 2 À Àd p ¼ 150 mm; L ¼ 50 m;
v 3 ; y 3 À Àd p ¼ 150 mm;
L ¼ 20 m
12.4 Rapid Piling Process of High-Speed Pneumatic–Hydraulic Composite Hammer
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