【作者】 肖诗云；

【导师】 林皋；

【作者基本信息】 大连理工大学 ， 水工结构工程， 2002， 博士

【摘要】 本文对混凝土进行了动态抗拉抗压试验，并根据试验结果，建立了混凝土一致粘塑性Drucker-Prager模型和一致粘塑性Willam-Warnke三参数模型，最后对溪洛渡拱坝进行动力非线性地震反应分析，探讨了应变率对高拱坝地震反应的影响。 本文在分析高拱坝特点的基础上，对混凝土进行了动力抗拉抗压试验，研究了应变率对混凝土动态抗拉抗压强度特性的影响，给出了混凝土动态抗拉抗压强度增量与应变率对数之间的拟合公式；分析了应变率对混凝土弹性模量、峰值应力时的应变、泊松比和混凝土吸能能力的影响。在分析混凝土静动力本构模型的基础上，着重分析了混凝土的屈服强度与混凝土内变量(塑性应变或塑性应变功)以及混凝土的动态抗拉抗压强度增量与内变量的变化率之间的关系，为建立混凝土的动态本构模型打下了基础；同时，也研究了湿度条件对混凝土应变率与混凝土动态抗拉抗压强度及动态变形特性关系的影响。 本文在分析试验的基础上，根据一致粘塑性本构模型的概念，对混凝土常用的静态本构模型Drucker-Prager模型和Willam-Warnke三参数模型进行改造，引入应变率的影响，建立了一致粘塑性Drucker-Prager模型和一致粘塑性Willam-Warnke三参数模型，并与试验结果进行了比较，结果表明模型能够较好地反映混凝土在单轴情况下的动力特性，同时分别用算例讨论了应变率对结构动力反应的影响，从数值算例的结果可以看出：在结构的响应中，考虑了应变率的影响后，混凝土的变形及应力大小与分布发生了较大的变化，因此，应变率对混凝土结构的影响是一个不容忽视的因素。 本文计算了溪洛渡拱坝线弹性模型、率无关和率相关Drucker-Prager模型、率无关和率相关Willam-Warnke三参数模型的地震反应，并初步探讨了应变率对拱坝地震反应的影响，计算结果表明拱坝在地震反应过程中，拉应力成为拱坝设计的控制应力，考虑应变率的影响后，拱坝抗拉强度和拉应力都得到了提高；而由于拱坝具有较高抗压能力，压应力没有达到屈服，因而应变率对其影响甚微。同时，考虑到应变率的影响后，结构的总应变和总应变率没有发生明显的变化，但是塑性应变和塑性应变率发生了较大的变化。本文的计算结果为拱坝的设计和拱坝抗震安全性评价提供了参考。更多还原

【Abstract】 The dynamic tension and compression experiments of concrete are carried and according to these results, the consistency viscoplastic Drucker-Prager model and Willam-Warnke three-parameter model have been built. Finally, nonlinear seismic responses of Xiluodu arch dam are analyzed to research the effect of strain rate on seismic responses of high arch dams.Based on analyzing behavior of high arch dams, the dynamic tension and compression experiments are carried to research the effect of strain rate on the dynamic tension and compression strength of concrete, and the empirical relationships between the dynamic strength increment and the logarithm of strain rate are given. The relationships between strain rate and the elastic modulus, critical strain, Poisson’s ratio and energy absorption capacity of concrete are still studied. Analyzed and compared the static and dynamic constitutive models, the relationship between the yield strength of concrete and internal variable (plastic strain or plastic strain work) and the relationship between the dynamic uniaxial tension and compression strength increment and rate of internal variable are important to building the dynamic constitutive models, so in this paper these relationships are principally and systematically studied. These works provide firm basis for establishing the dynamic constitutive model of concrete. At the same time, to research the influence of humidity of concrete on the relationship between dynamic behavior of concrete and strain rate, the concrete specimens are saturated with water for one month and the dynamic tension and compression experiments of these specimens are also carried. By contrasted these results with those of unsaturated specimens, the humidity of concrete affects the dynamic strength and dynamic behavior of concrete.According to the concept of consistency viscoplastic constitutive model and the results of these dynamic tension and compression experiments, the static Drucker -Prager model and Willam-Warnke three-parameter model are modified by considering the effect of strain rate to consistency viscoplastic Drucker-Prager model and consistency viscoplastic Willam-Warnke three-parameter model. Compared these models with experimental results, it shows that these models can well represent uniaxial dynamic tension and compression behavior of concrete. To research the effect of strain rate on dynamic behavior of concrete structures, the dynamic responses ofconcrete beams under impact loading are calculated and analyzed at linear elastic model, rate-independent and rate-dependent Drucker-Prager model, rate-independent and rate-dependent Willam-Warnke three-parameter model. It shows that the displacement, stress magnitude and distribution of beam change greatly. So, the influence of strain rate on dynamic response of concrete structures is important and inneglectable.Nonlinear seismic responses of Xiluodu arch dam are analyzed at linear elastic model, rate-independent and rate-dependent Drucker-Prager model, rate-independent and rate-dependent Willam-Warnke three parameter model to research the effect of strain rate on seismic responses of high arch dams. It shows that tension stresses become the control stresses of design and aseismic safety evaluation of high arch dams. After considering the effect of strain rate, the tension stresses and tension strength of concrete increase apparently, but the compression stresses and compression strength change very little because the compression stresses are not exceed to the compression yield strength of concrete. At the same time, the magnitude and distribution of total strain and total strain rate don’t change but those of plastic strain and plastic strain rate vary greatly. The calculation results provide reference for design and aseismic safety evaluation of high arch dams.更多还原