关键词: 硬填料, 应力-应变关系, 三轴试验, 本构模型

Abstract: Hardfill is a new type of architectural material for dam construction, with a wide application prospect. It is produced by adding low content cementitious material and water to rock-based material, and mixing them with simple device. Its mechanical performance lies between concrete and rockfill material. For further understanding and appreciating the mechanical behavior of hardfill material, a series of large-scale triaxial tests were performed on hardfill specimens at different ages. And strain-stress behavior of hardfill was investigated, showing that the failure strength of hardfill material follows the Mohr-Coulomb strength theory; with the age increasing, cohesion varies a lot while friction angle differs little. By subtracting stress-strain curves of rockfill, which represent the initial conditions of hardfill, from that of hardfill, the effect of cementation on stress-strain relationship was discussed. Based on the analysis of these results, an age-related constitutive model of hardfill was developed, which is a parallel model consisting of two components, rockfill component and cementation component. The rockfill component represents the conventional rockfill without any cementitious material, which reflects the influence of rockfill by playing a role of skeleton of this cement-rockfill mixture. The cementation component characterizes the impact of cementation. Moreover, comparison was made between simulated and experimental results, showing that the parallel model could reflect the mechanical characteristics of both rockfill-like nonlinearity and concrete-like age-relativity. In addition, a simplified method for determination of parameters was proposed.

Key words: hardfill material, stress-strain relationship, triaxial tests, constitutive model