混凝土坝长期变形特性数值分析及安全监控方法研究

Previous studies show that concrete dam deformation characteristics for a long time is potential factors leading to major hydraulic engineering accident at home and abroad. And concrete dam deformation characteristics for a long time is also the important evidence to judge dam’s safe operation. At present, systematic research about the long-term deformation characteristics of concrete dam is less. In this project, theory and method such as dam theory, mathematics and mechanics calculation method, scientific computing will be applied, combined with modern testing technology, in-situ monitoring, laboratory simulation test and numerical analysis, concrete dam long-term deformation characteristics under complicated environment and load were studied systematically. Based on the theory of fractional calculus, the simulation analysis model which can describe macroscopic mechanical properties accurately of dam concrete and dam foundation rock mass was built. Besides, numerical analysis theory and method of concrete dam long-term deformation characteristics under constant load was put forward. Moreover, evolution law and behavior characteristics of dam materials and structural mechanics performance was revealed. Lastly, coupling mechanism of concrete dam seepage field and stress field was analyzed and two filed coupling function model reflecting the long-term deformation characteristics of concrete dam was built synthetically, which revealed evolution mechanism and driving laws of concrete dam long-term deformation characteristics under complex environment. On the basis of above study, for temperature component defects existing in the concrete dam safety monitoring theory, concrete dam safety monitoring model with higher accuracy was built.

前期研究表明，混凝土坝长期变形特性是导致国内外重大水利工程事故的潜在因素，同时又是评判大坝安全运行的重要依据，目前有关混凝土坝长期变形特性的系统研究较少。本项目拟综合运用坝工理论、数学和力学计算方法、科学计算等理论与方法，结合现代测试技术、原位监测、室内仿真试验以及数值分析，系统研究复杂环境和荷载作用下混凝土坝长期变形特性，基于分数阶微积分理论，构建能较精确描述坝体混凝土和坝基岩体宏观力学性能的仿真分析模型，提出常载作用下混凝土坝长期变形特性的数值分析理论与方法，揭示大坝材料和结构力学性能演变规律和行为特征；进而，分析混凝土坝渗流场与应力场耦合机理，构建能综合反映长期变形特性的混凝土坝两场耦合作用模型，揭示复合环境作用下混凝土坝长期变形特性的演化机理与驱动规律；在上述研究的基础上，改进现有混凝土坝变形安全监控理论中变形温度分量存在的缺陷，构建精度较高的混凝土坝变形安全监控模型。

综合运用小波分析、相平面理论、分数阶微积分、有限元等数学理论和方法以及力学和坝工知识，系统研究了混凝土坝长期变形特性数值分析及安全监控建模方法,主要研究内容如下：（1）研究了提取大坝变形监测序列长期变形趋势项的方法；提出了分析混凝土坝长期变形特性的方法；探讨了黏弹塑性基本元件的力学特性以及力学本构模型的组合方式，研究了力学元件组合本构模型的辨识技术，建立了相应的二维和三维本构方程。（2）研究了混凝土坝渗流场与应力场耦合机理及分析方法，提出了考虑渗透力作用的混凝土坝长期变形特性数值分析方法；探讨了两场耦合下的有限元分析方法，建立了渗流与应力两场直接耦合的总体控制方程组，给出了混凝土坝长期变形有限元分析步骤，并编制了相应的分析程序。（3）探究了传统温度分量因子存在的不足，探究了环境温度在混凝土坝体中热传导滞后效应，改进了温度分量表达式，构建了精度较高的混凝土坝安全监控模型。针对混凝土坝自动化变形监测数据难免存在噪声成分，且变形与环境影响因素间呈现出复杂的非线性关系等问题，提出了了基于奇异谱分析与支持向量机的混凝土坝变形监控模型。