混凝土安全壳预应力施工模拟与变形监测

    Prestressed Construction Simulation and Deformation Monitoring of Concrete Containment Vessel

    • 摘要: 为了准确估计预应力施工过程中混凝土安全壳变形,以某核电站安全壳为背景,利用有限元软件ANSYS的重叠单元和生死单元技术,考虑混凝土弹性模量随龄期变化的影响,建立复杂实体有限元计算模型,结合现场预应力摩擦试验,分析时间相关的预应力损失与混凝土徐变对安全壳变形的影响. 结果表明:考虑混凝土收缩徐变与预应力筋应力损失等因素的影响,无论穹顶观测点,还是筒体观测点,考虑混凝土收缩徐变和预应力筋的应力松弛引起的应力损失时变的位移与现场实测的位移变化规律一致,而且更接近于现场实测位移. 预应力筋应力松弛引起的预应力损失时变对安全壳变形影响较小,但混凝土收缩徐变引起的预应力损失时变不容忽视,二者不存在相互影响. 对安全壳进行考虑混凝土收缩徐变以及其引起的预应力损失时变力学分析,可更加准确预测徐变对核电站安全壳长期变形的影响,从而为安全壳设计提供理论依据和技术支撑.

       

      Abstract: In order to accurately estimate the deformation of concrete containment vessel during the prestress construction, this article is set in a nuclear power plant containment, the overlap element as well as birth and death element technology is used so as to take into account the effect of time-dependent elastic modulus of concrete, the complex finite element solid model is established, and prestress friction field test is combined, the influence of time dependent prestress loss and concrete creep on the deformation of containment vessel is then analyzed, the results show that the change law of displacement without considering stress loss time-varying caused by shrinkage and creep of concrete and stress relaxation of prestressed tendon is consistent with that of field test displacement, considering concrete shrinkage and creep and stress loss of prestressed tendons, and it is more close to the actual measured displacement. prestress loss caused by stress relaxation of prestressed tendons is less affected by the deformation of containment vessel, but prestressed loss caused by the concrete shrinkage and creep can not be ignored, there is no interaction between the two. Time varying mechanics analysis taken concrete shrinkage and creep and its prestress loss into consideration is carried out during the prestress construction of containment vessel, effect of creep on the long-term deformation of a nuclear power plant containment vessel is accurately predicted, so as to provide the theoretical basis and technical support for the containment vessel design.

       

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