Equations for Compression Index Approximation

Abstract

Compression indices for clay sediments, which are based on simple soil-classification properties, save both time and expense involved with consolidation testing. Equations reported in the literature for prediction of compression indices are generally listed with regions (or limits) of applicability. A basic equation (or model) that could be used for most normally consolidated clay sediments, regardless of geographical location, was needed. Void ratio–log pressure curves for clay sediments showed that equilibrium void ratios are related to both clay properties and overburden pressure. Published data permitted derivation of an equation that relates compression index to both void ratio and liquid limit. Comparisons are made between this two-parameter model, available test data, and published compression-index equations.