倾斜岩层上核岛结构地震响应及动力损伤机理研究

Nuclear island structure is the core area of the nuclear power engineering, its seismic safety is extremely important. This project researches the seismic response and dynamic damage mechanism of nuclear island structure on inclined rock formation by using finite element analysis method. At first, considering the dynamic strengthen, fatigue damage and hysteretic characteristics of rock mass, the viscoelastic plasticity model will be established by the rock dynamic characteristics test under cyclic loading, moreover, the finite element analysis module which can describe the rock dynamic characteristics will be programmed and verified in ABAQUS software. Secondly, considering the the nonlinear dynamic characteristics of rock, soil and structure, based on different rock shear wave velocity, soil shear wave velocity, dip angles of rock formation and foundation embedded conditions, the 2D finite element numerical analysis has been carried out to research the dynamic interaction characteristics between rock formation-nuclear island structure-soil system, furthermore, the influence of nuclear island structure seismic response by different foundation embedded conditions are obtained. Finally, the seismic response characteristics of rock-socketed foundation nuclear island structure on inclined rock formation are researched by the 3D finite element numerical analysis, then the dynamic damage space-time evolution progress and mechanism of nuclear island structure will be revealed. Otherwise, the aseismatic method is proposed. This research provides theoretical support for the site selection and seismic design of nuclear island structure.

核岛结构是核电工程的核心区域，其抗震安全极其重要。本项目拟采用有限元数值分析方法，对倾斜岩层上核岛结构地震响应及动力损伤机理进行研究：开展循环荷载作用下岩石的动力特性试验，建立考虑岩体动力强化特性、损伤特性及滞回特性的岩体粘弹塑性本构模型，并在ABAQUS软件中开发可描述岩体在循环荷载作用下动力特性的有限元分析模块；考虑岩体、土、结构的动力非线性特性，基于不同的岩层、侧向地基土剪切波速、岩层倾角及基础埋置条件，进行二维有限元数值分析，得到岩层-核岛结构-侧向地基土系统的动力相互作用特性，并给出基础埋置条件对核岛结构地震响应的影响；对倾斜岩层上嵌岩基础核岛结构的地震响应进行三维有限元数值分析，给出核岛结构的地震响应特征，揭示核岛结构动力损伤的时空演化过程及机理，并提出震害防治方法。本研究可为核岛结构的选址和抗震设计提供参考和理论支持。

核岛结构是核电工程的核心区域，其抗震安全极其重要。多数情况下核岛结构基础可能支承在水平或者微倾的岩层上，结构地下部分侧面为厚度不等的地基土和风化岩层所包覆，因此核岛结构的地震反应受到复杂的岩-土-结构动力相互作用影响，并与多种介质动力非线性特性相关。本项目开展循环荷载作用下岩石的动力特性试验，通过剪应变幅值与循环动剪切模量幅值的关系，建立修正的Davidenkov本构模型，以模拟岩体在动力荷载作用下产生的强化及软化现象，获得不同强度等级、加载频率下的岩体的粘弹性本构模型参数，并在ABAQUS软件中完成其有限元数值分析模块的开发；通过建立水平或微倾岩层上的岩-土-CAP1400核岛结构体系二维有限元分析模型，基于全非线性条件给出了岩层倾斜度（倾角）对岩-土-结构动力相互作用下CAP1400核岛结构地震响应的影响规律，探讨了核岛结构的损伤特征及机理；通过建立岩-土-CAP1400核岛结构体系三维有限元模型，给出了岩石-土地基软硬变化或纯基岩地基条件对核岛结构地震响应的影响，并给出了不考虑土-结构相互作用的地基剪切波速建议值，探讨了CAP1400核岛结构损伤的机理及地震响应的空间效应；此外还拓展讨论了核电安全壳混凝土在压缩动态性能下的尺寸效应。研究成果具有重大的实用价值和现实意义，可为核岛结构的选址和抗震设计提供参考和理论支持。