混凝土损伤破坏强非线性分析和不确定性量化是国际研究前沿富有挑战性的难题，其研究解决是实现从“材料到结构”一体化分析和设计的关键所在，具有重要的科学意义和工程价值。在优秀青年基金和面上项目研究成果的基础上，将统一相场损伤理论与随机场建模、随机响应分析有机结合，研究提出混凝土微裂缝演化和细观非均质结构的宏观表征方法，深入分析混凝土损伤破坏过程中能量等效原理和概率守恒原理的内在机理，系统建立混凝土损伤破坏强非线性分析和不确定性量化的随机相场模型理论及其数值算法；在此基础上，通过尺度敏感性直接考虑混凝土尺寸效应的影响，提出一类适用于大型混凝土结构损伤破坏分析的多尺度方法，对极限承载力、破坏模式、能量耗散等结构随机响应进行全概率量化，并通过各种试验加以验证，从而揭示材料力学性能非线性和随机性对混凝土结构损伤破坏行为的影响规律，为基于可靠度的混凝土结构优化设计和安全评估提供重要理论基础和关键技术支撑。

It is a great challenging issue to the modeling, analysis and uncertainty quantification of complex responses during the damage and failure processes of concrete. It also plays a crucial role in realizing the integration of analysis and design “from materials to structures”, presenting significant interests to both scientific and engineering communities. Aiming to solve the above issue, in this proposal our previously proposed unified phase-field theory for both brittle fracture and quasi-brittle failure is combined synthetically with the random field modeling and stochastic structural analysis. Microcracks evolution and mesoscopic inhomogeneity of concrete are modeled on the macroscopic scale using the unified phase-field theory and random field method, respectively. The intrinsic mechanisms of energy equivalence and probability conservation are studied in depth, leading to establishment of the stochastic phase-field theory and the numerical algorithm for the nonlinear analysis and uncertainty quantification of damage and failure processes in concrete. Then, the scale sensitivity analysis is employed directly to characterize the influences of size effect typically for concrete, resulting in an efficient multiscale method for the stochastic analysis of damage and failure in massive concrete structures. The stochastic responses of limit load capacity, failure mode and energy dissipation are quantified and validated by comprehensive tests. With the prospected research achievements, it is promising to uncover the laws governing influences of nonlinearity and randomness in material mechanical properties on the responses in concrete structures, and to provide important theoretical basis and key technical support for the reliability-based design optimization and safety assessment of concrete structures.