Reliability Analysis of Pile Considering Spatial Variability of Soil Properties

To investigate the influence of spatial variability on the bearing characteristics and reliability of pile under vertical compression, a numerical model of pile in spatially various soil is developed. The KL-FORM is employed to analyze the reliability of pile for the ultimate limit state of bearing capacity. The influence of spatial variability of soil's undrained shear strength and elastic modulus on the reliability index of the pile is analyzed. Moreover, the influence of spatial variability of soil properties on the pile-soil interface parameters are investigated. Results show that the cohesive strength and the elastic modulus of pile-soil interface should be considered as variables which vary with the discrete values of random fields of soil properties. The spatial variability of elastic modulus influences the shape of load-displacement curve, but it does not influence the bearing capacity and the reliability index of the pile. The reliability index of the pile decreases with increasing coefficient of variation of undrained shear strength and vertical autocorrelation distance.

Keywords: Pile, Spatial variability, Random field, Karhunen-Loève expansion, Reliability index