Hyperbolic Stress‐Strain Parameters for Silts

Abstract

The hyperbolic stress‐strain model has been shown to be valid for modeling the nonlinear stress‐strain behavior of soils prior to failure in soil‐structure interaction analyses. However, guidelines for selecting hyperbolic stress‐strain parameters for silts have not been published to date. To fill this need, a series of isotropically consolidated‐drained and consolidated‐undrained triaxial tests were performed on freshly deposited, normally consolidated silts and clayey silts to provide guidance for selecting hyperbolic parameters for these materials. The effect of clay mineral content and dry unit weight on the hyperbolic parameters was investigated by reconstituting specimens at clay mineral contents of 0, 10, 20, 30, and 50% by dry weight and at standard Proctor relative compactions of 85, 90, 95, and 100%. At low clay mineral contents, the normally consolidated silt exhibited dilative shear behavior while a contractive behavior was observed at high clay mineral contents. The transition from dilative to contractive shear behavior is controlled by clay mineralogy. Due to the dilative behavior of the normally consolidated silt mixtures, failure criteria of maximum deviator stress and maximum pore‐water pressure were used to obtain the Mohr‐Coulomb shear strength parameters from the drained and undrained triaxial tests.