Schmertmann
The Schmertmann method determines the maximum pressure at pile base pmax, base as follows:
where: | αp | - | |
qupr | - | modified equivalent average cone tip resistance |
where: | qc1, qc2 | - |
In cohesionless soils the analysis takes into account the influence of overconsolidation (OCR).
The maximum shaft friction pmax,shaft is given by following formulas:
- for cohesionless soils:
where: | K | - | |
| - | mean value of penetrometer sleeve local friction fs in the interval given by bracket subscript | |
As | - | area of the pile shaft surface in a given interval | |
d | - | diameter of pile | |
D | - | embedded pile length |
- for cohesive soils:
where: | αs,i | - | shaft friction coefficient according to Tomlinson in the ith layer |
| - | mean value of penetrometer sleeve local friction fs in the ith layer | |
As,i | - | area of the pile shaft surface in the ith layer |
Literature:
Schmertmann J.H.: Guidelines for Cone Penetration Test, Performance and deign, U.S. Departments of Transportation, report No. FHWA-TS-78-209, Washington,D.C., 1978.