Prediction of Undrained Behavior of Isotropically and Anisotropically Consolidated Firoozkuh Sand: Instability and Flow Liquefaction

Abstract

Recent experimental findings highlight the impact of anisotropic consolidation on triggering flow liquefaction failures. Results of a series of undrained tests on isotropic and anisotropic consolidated Firoozkuh sand are reported. It was observed that very loose and loose samples are very prone to flow liquefaction; however, the samples in a medium-loose state can withstand flow and limited flow liquefaction effectively for an initial mean principal effective stress less than 300 kPa. The mechanical behavior of isotropically and anisotropically consolidated samples of Firoozkuh sand in very loose, loose, and medium-loose states was simulated realistically by a state-dependent elastoplastic constitutive model. For highly anisotropic consolidated samples, numerical simulations confirmed that flow liquefaction in very loose and loose samples may be triggered easily without any warning. In addition, the stress ratio at the onset of flow liquefaction is not unique and greatly depends on the initial state and consolidation history.