深厚覆盖层高土石坝抗震安全性是我国西部地区水电开发需要解决的重大研究课题，面临着地震烈度高、覆盖层液化弱化风险高、空间变异性显著等挑战，传统土石坝动力分析方法难以合理反映真三维强非线性流固耦合动力过程中变形发展和超静孔压累积的物理机制，无法对工程设计、方案优化提供科学合理的依据。本文提出一种有限元-有限体积（FEM-FVM）流固耦合框架，为包括土石坝在内的岩土工程大规模动力分析提供有效手段；开展深厚覆盖层高土石坝动力分析，揭示了动力三维效应的规律及其物理机制，阐述了大规模三维弹塑性动力流固耦合仿真的极其重要性；发展了随机全显式耦合方法（RFECM），阐明了空间变异性对土石坝动力响应、覆盖层孔压累积的影响规律。主要取得以下创新性成果：（1）提出了适用于岩土工程的高性能流固耦合求解算法，为深厚覆盖层高土石坝动力分析提供有效手段。搭建了一种有限元-有限体积框架，开发了全隐式耦合方法（FICM）、全显式耦合方法（FECM）、固显流隐耦合方法（SEFIM）等耦合算法，系统研究了不同算法的准确性、求解稳定性和并行可拓展性，研究证明了FECM和SEFIM在解决数千万自由度的大规模岩土工程流固耦合仿真问题方面具有明显的优势。（2）基于精细化建模和弹塑性动力流固耦合仿真，系统分析了深厚覆盖层高土石坝的动力响应，揭示了三维效应的规律及其产生机理。研究开发了砂土液化大变形本构模型的数值算法，并基于国际地震液化试验与分析计划（LEAP）进行了验证。通过不同覆盖层分布方案、不同精细化模型、不同动力分析方法的对比研究，揭示了动力响应的三维效应和精细化建模的重要性。开展了深厚覆盖层高土石坝的弹塑性动力流固耦合仿真，阐明了变形、加速度和超静孔压的分布规律。研究表明，弹塑性动力流固耦合分析是深厚覆盖层高土石坝抗震设计的有效工具。（3）发展了考虑参数空间变异性的RFECM，揭示了覆盖层变异性对高土石坝动力响应的影响规律，分析了变异系数的影响。研究在FECM的基础上发展了考虑土性参数变异性的RFECM，并针对LEAP-ZJU1模型试验砂土和高土石坝深厚覆盖层密实度变异性和变异系数进行了分析，揭示了其对变形和超静孔压比的影响规律。

Hydroelectricity development in Southwest China has raised the need for research on seismic safety of high rockfill dam on thick deposit. Facing challenges such as high seismic intensity, high rick of deposit liquefaction, and significant spatial variability, traditional seismic analysis methods for rockfill dam prove inadequate to reflect the physical mechanisms of deformation development and excess pore water pressure (EPWP) accumulation within the dam-deposit system during a three-dimenational strong-nonlinear solid-fluid coupled dynamic process, failing to provide scientific and rational basis for engineering design and optimization. This thesis proposes a finite element method and finite volume method (FEM-FVM) coupled framework, which provides an effective method for the large-scale dynamic analysis of geotechnical structures including rockfill dams. Dynamic analysis of high rockfill dam on thick deposit is conducted, revealing the laws and physical mechanisms of three-dimensional dynamic effect, as well as elucidating the importance of large-scale three-dimensional elastoplastic dynamic solid-fluid coupled simulation. Random fully explicit coupled method (RFECM) is developed, to illustrate the influence laws of spatial variability on dynamic response of rockfill dam and EPWP accumulation of deposit. The main achievements are as follows:(1) A high-performance solid-fluid coupled algorithm suitable for earthquake geotechnical engineering is proposed, providing an effective method for dynamic analysis of high rockfill dam on thick deposit. An FEM-FVM framework is proposed, and solid-fluid coupled algorithms including fully implicit coupled method (FICM), fully explicit coupled method (FECM), and solid explicit fluid implicit method (SEFIM) are developed. The accuracy, stability, and parallel scalability of different algorithms are systematically studied. It is concluded that FECM and SEFIM have significant advantages in solving large-scale geotechnical solid-fluid coupled simulation problems with tens-of-millions of degrees of freedom.(2) Base on refined modeling and elastoplastic dynamic solid-fluid coupled analysis, the dynamic response of high rockfill dam on thick deposit is systematically analyzed, revealing the laws and mechanisms of three-dimensional effect. A numerical algorithm for large deformation constitutive model of sand liquefaction is developed, and validated based on LEAP. Through comparative studies of different deposit distributions, refined models, and dynamic analysis methods, the importance of dynamic three-dimensional effect and refined model is revealed. Elastoplastic dynamic solid-fluid coupled simulation of high rockfill dam on thick deposit is conducted, and the distribution of deformation, acceleration and EPWP are studied. It is shown that an elastoplastic dynamic solid-fluid coupled method is effective tool for seismic design of high rockfill dam on thick deposit should adopt.(3) RFECM considering parameter spatial variability is developed, revealing the influence laws of deposit variability on the dynamic response of high rockfill dam and analyzing the influence of variation coefficients. RFECM considering soil parameter spatial variability is developed based on FECM, and the impact of density variability on deformation and EPWP is revealed through the density variability of LEAP-ZJU1 as well as the density variability of thick deposit, revealing the influence laws of variability on deformation and EPWP ratio.