Hiley Pile Driving Analyser
Dynamic driving formula — ultimate resistance from final set
Casing → rock tool
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Project
Pile reference
Date
Recorded by
1
Hammer & energy
Hammer type
(sets typical efficiency η
h
)
Drop hammer — winch released (0.80)
Drop hammer — trigger released (1.00)
Single-acting air / steam (0.85)
Double-acting air / steam (0.85)
Diesel hammer (0.80)
Hydraulic hammer (0.95)
Custom…
Hammer efficiency η
h
0–1
Ram weight × drop
Rated energy
Ram weight W
kN
1 tonne of ram ≈ 9.81 kN. Needed even in rated-energy mode (impact efficiency).
Drop height h
(effective stroke)
m
Rated energy per blow E
n
kJ
Manufacturer's energy per blow at the stroke used.
2
Pile & impact
Weight of pile + helmet + dolly P
(all driven parts)
kN
Estimate pile weight from dimensions
Material
Concrete
Steel
Timber
Length
m
Section area
mm²
Helmet + dolly weight
kN
Estimated P: —
Use this value
Cushion / dolly condition
(sets coefficient of restitution e)
Steel ram direct on steel pile, no dolly (0.55)
Helmet + composite plastic dolly, steel pile (0.50)
Helmet + timber dolly, steel pile (0.30)
Driving cap + plastic dolly, precast concrete (0.40)
Driving cap + timber packing, precast concrete (0.25)
Timber pile driven direct (0.25)
Custom…
Coefficient of restitution e
0–1
3
Driving record — set
Set per blow
Blow count
Final set s
(permanent penetration per blow)
mm/blow
Number of blows
Penetration
mm
4
Temporary compression c
Measured total
Components
Compute c
p
Total temporary compression c
(rebound from set card)
mm
c = c
c
+ c
p
+ c
q
, measured as elastic rebound of a blow trace.
Cap / cushion compression c
c
mm
Typically 3–9 mm depending on dolly / packing.
Pile elastic compression c
p
mm
Soil quake c
q
mm
Commonly taken as 2.5 mm.
c
p
= k
p
·R
u
·L / (A·E
p
) — solved simultaneously with the Hiley equation (quadratic in R
u
).
Pile length L
m
Section area A
mm²
Elastic modulus E
p
GPa
Steel 205 · concrete ≈30–35 · timber ≈10
Distribution factor k
p
1.0 end-bearing · ≈0.5 uniform shaft friction
5
Safety & target
Factor of safety
2.5 is usual for Hiley with measured c; range 2–3.
Target capacity
(optional)
kN
is a working load (×FoS applied)
Ultimate driving resistance R
u
—
kN
Allowable capacity R
a
—
kN
R
u
/ FoS
Efficiency of blow η
b
—
Energy to pile
—
kJ
Required set for target
—
mm/blow
Formula
R
u
=
η
h
· η
b
· W · h
s + c / 2
with η
b
=
W + e²P
W + P
−
(W − eP)²
(W + P)²
Resistance vs final set
Table view
How R
u
falls as the pile drives more per blow, with the current operating point. Hover or focus + arrow keys to read values.
Set (mm/blow)
Blows / 100 mm
R
u
(kN)
R
a
(kN)
Energy balance per blow
Driving system
W
h
helmet + dolly
pile
P
s
Set card — one blow
penetration