Page 64 - Handbook GEOTEKNIK_Final_Neat

Pile Bearing Capacity f and f for Cohesive and Cohesionless Soil
s
b

• Pile bearing capacity, Q comprises of two (2) components which are shaft resistance /
u
Clay
Sand
Silt
skin friction, Q and base resistance/end bearing, Q b Types of Soil (kN/m ) (kN/m ) (kN/m )
s
2
2
2
Unit Shaft C 1.7N 2N or K tan*
Q = Q + Q (kN) Resistance, f u v
u
s
b
s <100 kN/m for driving pile or borepile in residual soil or cohesive soil
2
• Shaft resistance / skin friction, Q s
Q = Σ Q = Σ f .A Base resistance/ 200N or 9*C 250N 400N
s
s
s
s
u
end bearing, f
b
Where f = Unit shaft resistance (kN/m )
2
s
A = Area of shaft (m ) 100N for borepile
2
s
• Base resistance/end bearing, Q b <10,000 kN/m for driving pile or borepile in residual soil or cohesive soil
2
Q = f .A b
b
b

Where f = Unit point resistance (kN/m ) Table 9: f and f for Cohesive and Cohesionless Soil
2
b
s
b
A = Area of base (m )
2
b
Note :

N = SPT N-value (nos. of blows / 300mm)
 = vertical stress adjacent to the pile = *h
v
48 PUBLIC WORKS DEPARTMENT MALAYSIA GEOTECHNICAL ENGINEERING HANDBOOK 49