Innovations of the UH model associated with a clue of stress-strain chain

One of the most fundamental issues in geotechnical engineering is deformation calculation. Within the elasto-plastic constitutive model framework, a new concept of stress-strain chain is proposed for the analysis of the computational process of plastic strain. The connotation of the chain is then demonstrated through seven stages, starting with six-component stress and ending with six-component plastic strain. The inadequacies of previous research on plastic strain computation induced by several factors such as anisotropy, dilatancy, hardening law, and hardening parameter are evaluated utilizing the stress-strain chain. Meanwhile, based on the stress-strain chain, innovations of the UH model such as the transformed stress method, the unified normalized compression line, and the unified hardening parameter are introduced and validated. It can be seen with the stress-strain chain that plastic volumetric strain and its assignment criterion are the keys to deformation calculation. Representative innovations of the UH model facilitate the efficiency of plastic strain calculation by accurately determining plastic volumetric strain and appropriate ratio relations. Through a foundation pit excavation case, the values and ratios of strain components predicted by the UH model are more reasonable and reliable. This demonstrates that the UH model enhances the accuracy of deformation calculations greatly.