Effective Stress Method
The effective stress method allows us to calculate the vertical bearing capacity of an isolated pile in both cohesive and non-cohesive soils. This method is suitable for drained conditions - i.e. conditions that prevail after sufficient time passed the construction.
The pile shaft resistance is given by:
where: | qs, j | - | shaft resistance in the jth layer |
βp,j | - | coefficients according to Bjerrum and Burland in the jth layer | |
σ0, j | - | average effective stress due to overburden acting along the pile in the jth layer | |
Asj | - | pile shaft area in the jth layer |
The pile base resistance is given by:
where: | qp | - | unit pile base resistance |
Ab | - | pile base area | |
Np | - | pile base resistance coefficient (according to Fellenius) | |
σp | - | effective stress due to overburden acting at pile base |