粗粒料蠕变行为本构模拟研究

    Constitutive modeling of creep behaviors of coarse-grained materials

    • 摘要: 基于粗粒料蠕变变化规律分析,提出了粗粒料蠕变指数型经验模型及最终蠕变相关表达式。在耦合破碎与摩擦耗能本构模型框架内,将上述蠕变经验表达式嵌入硬化规则,构建了粗粒料弹黏塑性本构模型。采用粗粒料三轴剪切与蠕变试验测试数据初步验证了上述模型的合理性与可靠性。对一粗粒料高填方体进行数值模拟,结果表明:模型预测所得应力的时空变化规律与现场实测变化趋势基本吻合;在竣工后近3 a内,高填方体沉降模型预测结果与监测结果较好吻合;粗粒料蠕变效应较为显著,是相关高填方体工后长期变形的重要诱因。

       

      Abstract: The creep empirical model, which is characterized as an exponential function, is proposed for coarse-grained materials (CGMs) based on analyses of their creep evolution, and the final creeps are described by the state-dependent formulations. Within a constitutive framework of coupled breakage and friction dissipation (CBFD), an elasto-visco-plasticity model is developed for CGMs by incorporating the above-mentioned creep formulations into the hardening rules of post CBFD elasto-plasticity model. The reasonability and reliability of this model are preliminarily verified using the test data of a series of triaxial creep tests on CGMs. The numerical simulation about a high embankment (HE) filled with CGMs shows that: (1) The temporal and spatial evolution of stresses predicted by this model in the HE agrees with the measured trend of stress change in the HE projects; (2) Within 3 years of pos construction, the model predictions of settlement in the HE are in good agreement with the in-situ measured results. (3) The creep effect of CGMs is remarkable, and it is a significant factor which results in the long-term post construction settlement of HE filled with CGMs.

       

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