The uncertainties in pile bearing capacity calculation relate numerous sources of different types. They concern the driving stage of the piles and their interaction with the soil which cannot be properly modeled, the representative of the samples of clayey soils and the reliability of laboratory or in situ tests from which the soil properties for the pile bearing capacity estimation can be provided. Furthermore the constitutive model of soil and the inherent variability and heterogeneity of soil properties contribute to the loss of reliability of the pile design results calculated by means of deterministic approaches. As regards the calculation of the bearing capacity of piles in cohesive soil for total stress conditions it must be measured the undrained shear strength cu over the pile depth and under the pile tip. The data set of the measurements of cu is generally not suffice to be statistically significant. Beside there is a well known Italian clayey formation with a lot of physical and mechanical soil data available, that is the Subapennine Blue clays. Loading proves on drilled piles are also available for these clays. Accordingly sensitivity analyses on both the undrained shear strength variability and the model uncertainty were carried out to investigate their influence onto the probability of failure corresponding to the working load of piles.
The bearing capacity of piles evaluated by means of load tests according to reliability calculations
VESSIA, Giovanna
2005-01-01
Abstract
The uncertainties in pile bearing capacity calculation relate numerous sources of different types. They concern the driving stage of the piles and their interaction with the soil which cannot be properly modeled, the representative of the samples of clayey soils and the reliability of laboratory or in situ tests from which the soil properties for the pile bearing capacity estimation can be provided. Furthermore the constitutive model of soil and the inherent variability and heterogeneity of soil properties contribute to the loss of reliability of the pile design results calculated by means of deterministic approaches. As regards the calculation of the bearing capacity of piles in cohesive soil for total stress conditions it must be measured the undrained shear strength cu over the pile depth and under the pile tip. The data set of the measurements of cu is generally not suffice to be statistically significant. Beside there is a well known Italian clayey formation with a lot of physical and mechanical soil data available, that is the Subapennine Blue clays. Loading proves on drilled piles are also available for these clays. Accordingly sensitivity analyses on both the undrained shear strength variability and the model uncertainty were carried out to investigate their influence onto the probability of failure corresponding to the working load of piles.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
