Cyclic instability behaviour of sand silt mixture under partial cyclic reversal loading

Abstract

Flow liquefaction is one of the most catastrophic failure phenomena in geotechnical engineering. It is a form of instability and can be observed during monotonic loading or cyclic loading. It is referred to as static instability/liquefaction for monotonic loading and cyclic instability for cyclic loading. To investigate the link between these behaviours, a number of stress controlled cyclic triaxial tests were carried out on loose sand-silt mixture under cyclic ‘reversal’ and ‘non-reversal’ loading condition. Cyclic reversal loading was partial reversal. Its peak-trough magnitudes were chosen in such a way that cyclic instability was triggered in compression side of the stress space. Thus it gives an opportunity to compare cyclic instability (both for partial ‘reversal’ and ‘non-reversal’) with static instability observed in monotonic loading condition. The test condition covers a range of initial mean effective confining stresses and void ratio. The equivalent granular state parameter was used to synthesize the test results irrespective of fines contents.