Effect of Spatial Correlation of Cone Tip Resistance on the Bearing Capacity of Piles

Abstract

The cone tip resistance (qc) from cone penetration tests (CPTs) is widely used to determine the bearing capacity of piles. Although it is widely known that soil properties are spatially correlated, the spatial correlation of qc is not considered in the current methods for predicting the bearing capacity of piles. In this paper, a probabilistic approach is presented for predicting the bearing capacity of driven piles in clay by considering the spatial correlation between qcsVn (the spatial average of qc of the bottom soil layer within the pile length) and qcbV (the spatial average of qc over an interval near the pile base). Parametric studies are conducted to evaluate the effect of the spatial correlation between qcsVn and qcbV on the bearing capacity of piles. The results indicate that it is important to consider the spatial correlation between qcsVn and qcbV in the probabilistic prediction of the bearing capacities of piles. Ignoring the spatial correlation between qcsVn and qcbV will underestimate the probability of failure and lead to unsafe design. Finally, 14 field test piles are analyzed with the presented approach to demonstrate the probabilistic prediction of the bearing capacity of piles by considering the spatial correlation of the CPT data.