Liquefaction characteristics of gravelly soil under cyclic loading with constant strain amplitude by experimental and numerical investigations

摘要

In order to investigate the liquefaction behavior and meso-mechanism of gravelly soil under cyclic loading with constant strain amplitude, the undrained dynamic triaxial test, CT scan test and numerical simulations by discrete element method (DEM) are performed. Effects of gravel content and the evolution of liquefaction nmeso-mechanism are analyzed respectively. Test Results show that the liquefaction resistance of gravelly soil increases considerably with the increasing gravel content due to growing in number of gravel-to-gravel contact. DEM simulations reflect the macro mechanical property of saturated gravelly soil in the cyclic triaxial test, and show anisotropy is the most important mechanical properties of gravelly soil liquefaction under cyclic loading with constant strain amplitude. In process of the liquefaction, the backbone force-chain is gradually destroyed, and magnitude of normal contact force decreases to zero until initial liquefaction. Both of the fabric and force chain evolution demonstrate a consistent deflection of the principal stress axis.