ABSTRACT
Analysis of monitoring and numerical calculation results shows development of non-monotonic stress and strain paths during monotonic loading and unloading of geotechnical structures. Stress paths calculated by FEM for different types of structures (embankment dam, shallow foundation, underground opening) are analysed in the paper with particular attention to the non-monotonic development of the shear stress level producing loading and unloading in shear. Correct simulation of soil stiffnes changes due to these paths is necessary for realistic displacement prediction. A check on capability of different constitutive models of geomaterials to account for this effect is made in the paper using unit response envelopes suggested by Gudehus (1979). Proper switch functions for variable moduli models and account for deviatoric hardening for elasto-plastic models are necessary for avoiding overestimation of displacements in numerical calculations of geotechnical structures.
