Hilley's Formula
Hilley's Formula
Hilley's Formula
Pile data
Size of R.C. Pile 250mm x 250mm
Pile Working Capacity (tons) 40
Factor safety allowed 2
R = Ultimate bearing capacity (tons) 80
K = Cooefficient of restitution 0.5 (for rc piles)
Equipment data
Type of hammer used
Weight of drive cap
H = height of free fall 300
P = Total pile weight (assumed penetration 24m) 36
C = Temporary Elastic compression (assumed) 12.5mm
W = Weight of hammer (tonnes) 5 tons
S = Set Penetration of the piles per blow 2.5mm/blow
e = Hammer efficiency 1 (for hydraulic driven hammer)
f = Efficiency factor
f= 5 + (0.5x0.5x3.6) f = 8 + (0.5x0.5x7.056)
5 + 3.6 8 + 7.056
0.686047 0.648512
Substitution for unknown value : (penetration set) Substitution for unknown value : (penetration set)
WHZ WHZ
R= R=
S + C/2 S + C/2
500
70.56
5mm
8 tons
m/blow
driven hammer)
350mm
e : (penetration set)
mm/10 blows