Some hysteresis effects of the behaviour of geologic media

A soil mechanics oriented theory of the hysteretic behaviour of materials under alternating loading is presented. Special attention is focused on the behaviour within the yield locus. The single hysteresis branches are described by piecewisely path independent laws with a variable compliance matrix depending on a scalar strain parameter. This parameter is chosen so that the polar symmetry of the unloading/reloading stress-strain curve in a uniaxial stress cycle is assured. The stress-strain constitutive laws are given either in incremental terms or in terms of finite quantities. The constitutive relations are valid piecewisely within the appropriately formulated stress reversal loci. Discrete and hierarchic memory of the cyclic behaviour is discussed and the rules for continuation, reactivation or generation of subsequent laws are formulated. Finally simple examples are discussed. © 1979.