STATISTICAL MODELING OF UNIT SKIN FRICTION BETWEEN PILES AND CORAL GRAVELLY SAND USING IN-SITU SPT DATA

Abstract

This paper presents a statistical analysis of unit skin friction between piles and coral sand layers, based on 245 in-situ Standard Penetration Test (SPT) records collected from a coral reef area. The unit skin friction was estimated using Meyerhof’s empirical correlation. Field data were used to assess the statistical characteristics of the pile-soil interface in coral sand. The results reveal that the distribution of unit skin friction does not follow a single normal (Gaussian) distribution, as is typical for terrestrial granular soils, but instead indicating the presence of multiple distinct geotechnical regimes. This distinctive feature reflects the unique interaction mechanism between piles and calcareous soil, which should be carefully considered in the foundation design of coastal and island structures.