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基于广义塑性理论建立了一个考虑堆石料颗粒破碎的弹塑性本构模型。模型采用随平均应力增加而减小的峰值摩擦角和特征点摩擦角来反映堆石料因颗粒破碎而表现出的峰值应力比与剪胀应力比的非线性,在此基础上确定塑性流动和加载方向向量;运用指数型压缩函数建立依赖于体积应变和平均应力的压缩参数λ,并构造随平均应力与剪应力水平而变化的塑性模量表达式。模型共有8个参数,均可通过等向或单向压缩和三轴压缩试验确定。为验证本文模型的合理性,依据试验资料确定了3种不同堆石料的本构模型参数,并对典型三轴压缩试验进行了模拟。3种材料的模型预测结果与试验数据均吻合良好,表明本文模型可合理反映了颗粒破碎对堆石料强度与变形特性的影响。
Based on the generalized plastic theory, an elastic-plastic constitutive model considering particle crushing of rockfill materials is established. The model uses the decreasing peak friction angle and the characteristic point friction angle as the average stress increases to reflect the non-linearity of the peak stress ratio and the dilatancy ratio of the rockfill material due to particle breakage, on the basis of which plastic flow and loading The compression parameter λ which depends on volumetric strain and average stress is established by exponential compression function and the plastic modulus expression is constructed according to the average stress and shear stress level. The model has a total of eight parameters, which can be determined by isotropic or unidirectional compression and triaxial compression tests. In order to verify the rationality of this model, the constitutive model parameters of three different rockfill materials were determined based on the experimental data, and the typical triaxial compression test was simulated. The prediction results of the three kinds of materials are in good agreement with the experimental data, indicating that the model can reasonably reflect the influence of particle breakage on the strength and deformation characteristics of rockfill materials.