胶结砂砾石料的动力特性及损伤本构模型

Dynamic characteristics and damage constitutive model of cemented sand and gravel materials

  • 摘要: 胶结砂砾石料是一种新型且具有广泛应用前景的筑坝材料,但对胶结砂砾石料的动力特性缺乏足够的了解。开展了胶结砂砾石料的循环三轴动力剪切试验,探究胶结砂砾石料的动力特性,结果表明围压和胶凝掺量均会影响滞回曲线的形态,随围压和胶凝掺量的增大,动剪模量增大、阻尼比减小。在广义Kelvin模型上串联损伤元件,构建了动力损伤本构模型,根据能量交互原理定义损伤变量D,并修正动剪模量和阻尼比的理论公式,推导得出损伤本构模型的刚度矩阵,该模型对胶结砂砾石料三轴动力剪切试验具有良好的拟合效果。并以某胶结砂砾石坝为例,讨论了坝体在动力荷载作用下的加速度响应及损伤分布规律。

     

    Abstract: Cemented sand and gravel (CSG) material is a novel dam construction material with promising applications. However, the dynamic characteristics of CSG materials remain inadequately understood. Cyclic triaxial dynamic shear tests were conducted to investigate the dynamic characteristics of CSG materials. The results indicate that confining pressure and cement content significantly influence the shape of the hysteresis curves. With increasing confining pressure and cement content, the dynamic shear modulus increases while the damping ratio decreases. A dynamic damage constitutive model was constructed by integrating damage elements into a generalized Kelvin model. The damage variable D was defined based on the energy interaction principle, and theoretical formulas for the dynamic shear modulus and damping ratio were modified accordingly. The stiffness matrix of the damage constitutive model was derived, and the model demonstrated good fitting performance for the triaxial dynamic shear tests of CSG materials. Additionally, the acceleration response and damage distribution patterns of a CSG dam under dynamic loading were analyzed using a case study.

     

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