Undrained Behaviour of Cohesionless Soils Under Cyclic and Transient Loading

An experimental approach using the conventional axisymmetric triaxial apparatus suggested the introduction of a new concept the characteristic state for cohesionless soils, associated with an interparticle friction angle which is an intrinsic factor corresponding to the interlocking capacity of the granular material. It offers a rather convenient framework for interpreting different mechanical aspects of soil behaviour under undrained cyclic loading. Sand liquefaction occurs only under alternating cyclic loading reaching the characteristic thresholds on both sides of zero deviatoric stress