Development And Application Of Unified Hardening Model In FLAC3D

Based on the MCC model,the over-consolidated unified hardening model(UH model)proposed by Yao et al can describe many characteristics of clays well,including stress-strain relationships,stress dilatancy,strain hardening and softening,and stress history dependency.According to the assumption of elastic-plastic model and solution of a quadratic equation,the computational scheme of UH model in FLAC3 D is derived.Based on the secondary developing platform,the UH model is developed in FLAC3 D with Visual C++ environment.Using this program,numerical simulations of triaxial compression,triaxial extension and plane strain tests are performed,which shows a good agreement with the analytic solution.The comparison with the Cam-clay model shows UH model have several advantages in stress dilatancy,strain softening and reloading features.Then,the advantage of FLAC3 D in using constructive models with nonassociated flow rule is discussed.Finally,through one test case,it is verified that the developed program can handle multiple elements.