An Empirical Correlation for Compressibility of Shallow Depth Clays in Deepwater Gulf of Mexico

Abstract

Settlement of subsea structures is an important design consideration, yet it is typically estimated using empirical correlations. A total of 74 consolidation test results from deepwater projects are collected and analyzed to develop an empirical correlation for shallow depth (less than 20 m) deepwater clays in the Gulf of Mexico. Compression indexes with and without clay structural effects are separately considered. Most of the published empirical correlations are irrelevant to offshore clays and the commonly used empirical correlation that uses liquid limit could significantly underestimate the peak compression index of deepwater offshore clays. Initial void ratio is selected as an independent variable for peak compression index estimation. A power function type correlation is proposed between the peak compression index and initial void ratio. With the lower and upper bounds (±30 %), the proposed empirical correlation encompasses the majority of the peak compression index data considering the structural effects. The proposed correlation is applicable for deepwater clays in the Gulf of Mexico having initial void ratios between 1 and 4.