Settlement of Piles According to Poulos
The basic assumption of the analysis is the determination of the load at the shaft resistance activation Rsy. At this point the shaft resistance no longer increases, further load is taken by the pile base only. This force is given by equation:
where: | Rs | - | pile shaft resistance [N] |
β | - | proportion of applied load transferred to pile base [-] |
The proportion of applied load transferred to pile base β is provided by:
where: | β0 | - | base-load proportion for incompressible pile |
Ck | - | correction factor for pile compressibility | |
Cν | - | correction factor for Poisson's ratio of soil | |
Cb | - | correction factor for stiffness of bearing stratum |
The corresponding value of settlement sy at shaft resistance activation Rsy is given by:
where: | I | - | settlement-influence factor [-] |
Es | - | average value of secant modulus of soil along the pile shaft [MPa] | |
d | - | pile diameter [m] | |
Rsy | - | load at the shaft resistance activation [N] |
The settlement-influence factor I is given by:
where: | I0 | - | basic settlement-influence factor |
Rk | - | correction factor for pile compressibility | |
Rb | - | correction factor for stiffness of bearing stratum | |
Rv | - | correction factor for Poisson's ratio of soil |
The overall limit settlement slim is provided by:
where: | I | - | settlement-influence factor [-] |
Rbu | - | ultimate pile base bearing capacity [N] | |
β | - | proportion of applied load transferred to pile base [-] | |
d | - | pile diameter [m] | |
Es | average value of secant modulus of soil along the pile shaft [MPa] |
Literature:
Poulos, H. G. et. Davis, E. H.: Pile Foundations Analysis and Design. New York: John Wiley and Sons, 1980, chapters 5.3 and 5.4, pp. 84 - 100.