Comparison and Study on Constitutive Models for Coarse Grained Materials under Different Stress Path

Combined with triaxial test data of coarse-grained material, rationality verification and study of constitutive model used commonly in earth dam indicates that Duncan's E-B model and SHEN Zhujiang's double-yield-surface model both well reflect the stress-strain relationship of pre-broken coarse-grained material under general triaxial test. Using general triaxial test parameters, deformation of coarse grain calculated under the path of equal stress ratio is done; whose decrease of volume strain and increase of shear strain is great difference compared with the experimental result. Nonlinear elastic model and Shen Zhujiang's double-yield-surface model could fit the result of triaxial test under equal stress ratio well when they are modified combined with the stress path of equal stress ratio. the main reason of great calculation error is that elastic parameters obtained by general triaxial experiment are applied to calculate them under complex stress path in high rockfill dam, by assuming the elastic parameters independence on stress path. Reasonable stress-strain constitutive model must reflect dam's real loading stress path objectively.