考虑时效损伤的岩石黏弹塑性本构模型
Viscoelastic Plastic Constitutive Model of Rock Considering Aging Damage
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摘要: 目前多数本构模型难以同时描述软岩和硬岩的加速蠕变行为。为了反映岩石蠕变黏弹塑性力学行为,以广义Burgers模型作为基础模型,并验证其适用范围。引入损伤力学理论,建立考虑时效损伤的黏塑性体,与广义Burgers模型串联,从而得到一个新的黏弹塑性蠕变本构模型,并拓展为三维情形。以某水电工程边坡页岩为研究对象,开展三轴压缩蠕变试验,利用所建模型辨识页岩蠕变数据,求解模型参数,并进行敏感性分析。引用相关文献中不同硬度、类型岩石的三轴蠕变数据,引入三维Cvisc模型进行模拟对比,分析理论曲线和试验曲线,充分显示出所建模型的合理性和适用性。目前多数模型难以反映不同岩石加速蠕变特性,所建模型通过验证可描述不同类型、硬度岩石蠕变行为,对不同加速蠕变曲线仍有良好辨识能力,研究成果为岩石加速蠕变力学行为模拟和岩体工程长期稳定性研究提供一定参考。Abstract: At present,most constitutive models can hardly describe the accelerated creep behavior of soft rocks and hard rocks at the same time. A generalized Burgers model is used as the basic one to reflect the creep viscoelastic-plastic mechanical behavior of rocks and its application range is verified. Based on the theory of damage mechanics,a new creep constitutive model of viscoelastic-plasticity is obtained by establishing a viscoelastic-plastic body considering aging damage in series with the generalized Burgers model. Taking the slope shale of a hydropower project as the research object,the triaxial compression creep test is carried out. The creep data of shale are identified by the model,the model parameters are solved,and the sensitivity analysis is carried out.Based on the triaxial creep data of different hardness and types of rocks in relevant literature,a three-dimensional Cvisc model is introduced to simulate and compare,and the theoretical and experimental curves are analyzed,which fully shows the rationality and applicability of the model. At present,most models can hardly reflect the accelerated creep characteristics of different rocks. The model can describe the creep behavior of different types of rocks by verification,and still have good identification ability for different accelerated creep curves. The results provide some reference for rock accelerated creep mechanical behavior simulation and long-term stability study of rock mass engineering.