Phénomènes cycliques dans les sols pulvérulents

Abstract

Stress-strain behaviour of cohesionless soils under cyclic loading depends greatly on stress path. Experimental results using the conventional axisymmetrical triaxial apparatus demonstrates the importance of three essential features of soils response to the non-monotonic loading : — strain hardening reflecting the difference of stress-strain behaviour between first loading on virgin soil and following cycles of unloading-reloading ; — hysteresis of soils under cyclic loading due to an irreversible behaviour during each load cycle ; — stress paths enhancing mechanisms of deformation associated either with great volumetric strain or with predominant distortion strain. A new concept, « Characteristic State of Soil », is proposed for studying soils under cyclic loading in order to follow the rheological behaviour during the irreversible deformation process. The characteristic state concept is adequate for interpreting the different features of cyclic behaviour of cohesionless soils such as adaptation, accommodation, ratcheting, liquefaction, cyclic mobility or stabilization.