土的统一硬化本构理论及其工程应用

Drucker, the pioneer of plastic mechanics theory, proposed the first plastic constitutive framework for soils which unified both deformation and strength behaviors. Based on this framework and the fundamental mechanical characteristics of soils, Roscoe et al. proposed the Cam-Clay model, which is capable of quantitatively describing the deformation and strength behaviors of normally consolidated clay. In order to address the defects that Cam-Clay model cannot adequately predict the stress-strain characteristics of overconsolidated clays and sands, the following contributions have been achieved: (1) The unified hardening (UH) law is proposed, and the UH constitutive model is subsequently established. The UH model can accurately describe the stress-strain characteristics of normally consolidated clays, overconsolidated clays, and sands. This novel work answers one of the two Wroth-Houlsby’s Questions. The UH model is extended to take into account the influences of many complex soil behaviors, forming the UH constitutive system. (2) The generalized nonlinear strength criterion and the transformed stress method are proposed in order to accurately generalize the constitutive model to the three-dimensional stress space, which answers the second Wroth-Houlsby’s Questions. (3) The UH constitutive theory consists of the UH constitutive system, the generalized nonlinear strength criterion and the three-dimensional transformed stress method. It has been widely applied to the modelling of many geotechnical engineering problems, including three particular issues associated with the airport engineering, i.e., “pot cover effect” “intelligent early warning” and “intelligent compaction”.