堆石料的剪胀特性与广义塑性本构模型

以三轴试验成果为基础，考虑颗粒破碎引起堆石料剪胀比与应力比之间的非线性关系，提出了能够反映堆石料低围压剪胀、高围压剪缩特性的剪胀方程。在广义塑性理论框架内构造堆石料的塑性流动方向向量和加载方向向量，引入依赖于密实度与平均应力的压缩参数，构造随平均应力、剪应力比和密实度变化的塑性模量，建立了一个考虑颗粒破碎的堆石料弹塑性本构模型。阐述了该模型10个参数的确定方法，并通过模拟不同围压和不同应力路径下堆石料的三轴压缩试验资料验证了模型与参数的合理性。

Dilatancy behaviors and generalized plasticity constitutive model of rockfill materials

Based on the results of triaxial experiments on rockfill materials, a dilatancy equation is derived by considering the nonlinear dependence of the dilatancy stress ratio on the stress ratio (i.e. the ratio of the deviatoric stress to the mean stress). This equation reveals the deformation characteristics of rockfill materials induced by dilatancy appearing at low confining pressure and by shear shrinkage appearing at high confining pressure. Within the framework of the generalized plasticity theory, the plastic flow direction vector and the loading direction vector are deduced. A compression index is determined in terms of compactness-dependent and mean stress-dependent effects. Then the plastic modulus is formulated as a function of the mean stress, the shear stress ratio and the compactness. On the basis of above studies, a new elastoplastic constitutive model is derived by considering the particle breakage of rockfill materials. The methods are addressed to determine ten material parameters of this model. Finally, the proposed model is used to simulate the triaxial tests on rockfill materials under different confining pressures and stress-paths, and the simulation results are good agreement with the experimental data.