Characterization of Autocovariance Parameters of Detrended Cone Tip Resistance from a Global CPT Database

This paper compiles a cone penetration test (CPT) database, named Global-CPT/3/1196. It contains three CPT parameters (cone tip resistance, sleeve friction, and porewater pressure) from 1,196 CPT soundings taken at 59 sites worldwide. The spatially variable cone tip resistance corrected for porewater pressure (qt) soundings in the database are analyzed by a uniform procedure to characterize their autocovariance parameters consisting of a coefficient of variation, scale of fluctuation, smoothness, and hole effect. This is the first study that characterizes spatial variability based on a more complete set of three parameters: scale of fluctuation, smoothness, and hole effect. Previous studies were based on a single parameter (scale of fluctuation). The statistics of the autocovariance parameters and their inter-relationships are presented as a function of soil behavior type. These new statistics may be valuable for a future design founded on insufficient site investigation data: they can be used to obtain first-order estimates for the autocovariance parameters based on soil behavior type. Applications include data-driven site characterization and random finite-element analysis.