Scale effect of rockfill materials using super-large triaxial tests
摘要
A super-large triaxial apparatus and a common large triaxial apparatus are used to conduct triaxial tests on quarried rockfill materials with the maximum particle size dmax of 200 and 60 mm in parallel gradation. The study mainly focuses on the effect of particle size on the stress-strain relation, particle breakage, characteristic stress state and parameters of Duncan-Chang model. The results show that the peak friction angle of dmax=60 mm is higher than that of the dmax=200 mm, and the axial stain at the peak strength of dmax=60mm is smaller than that at dmax=200 mm. The phase transformation stress ratio of dmax=60 mm is higher than that at dmax=200 mm, and the volumetric and axial strains in phase transformation state are smaller than those at dmax=200 mm. The amount of particle breakage of dmax=200 mm is greater than that at dmax=60 mm. The secant elastic and bulk moduli at 50% stress level of dmax=60 mm are larger than those at dmax=200 mm. The parameters k and kb of Duncan-Chang model for dmax=60 mm are 1.22 and 1.38 times those for dmax=200 mm, respectively. This study may provide valuable experimental references for the constitutive model considering scale effect and the deformation analysis for rockfill structures.