基于统一相场理论的早龄期混凝土损伤与破坏分析:化-热-湿-力多场耦合与多重变形竞争  

COMPUTATIONAL MODELING OF DAMAGE AND FAILURE IN EARLY-AGE CONCRETE BASED ON THE UNIFIED PHASE-FIELD THEORY:CHEMO-THERMOHYGRO-MECHANICAL MULTI-PHYSICS COUPLING AND MULTI-DEFORMATION COMPETITION

作　　者：吴建营[1,2] 莫盛特 周浩 Wu Jianying;Mo Shengte;Zhou Hao(State Key Laboratory of Subtropical Building and Urban Science,South China University of Technology,Guangzhou 510641,China;School of Civil and Transportation Engineering,South China University of Technology,Guangzhou 510641,China)

机构地区：[1]华南理工大学亚热带建筑与城市科学全国重点实验室,广州510641 [2]华南理工大学土木与交通学院,广州510641

出　　处：《力学学报》2024年第12期3521-3536,共16页Chinese Journal of Theoretical and Applied Mechanics

基　　金：国家自然科学基金资助项目(52125801)。

摘　　要：受水泥水化、温度传输、水分传输和力学作用等多场耦合影响,早龄期混凝土会产生自收缩、热胀冷缩、干燥收缩和载荷变形等多重变形机制,由此导致核安全壳、隧道桥梁及水工大坝等大体积混凝土结构往往在建造期即出现裂缝,严重削弱结构的完整性、耐久性和安全性.探究早龄期混凝土裂缝产生的物理机理,对其萌生和发展进行精准分析预测并进行调控,是确保混凝土结构全生命周期安全服役的重要手段.在固体结构损伤破坏统一相场理论的基础上,合理反映上述化-热-湿-力多场耦合以及由此导致的多重变形相互竞争机制,建立了早龄期混凝土化-热-湿-力多场耦合相场内聚裂缝模型,并将其应用于若干早龄期混凝土损伤破坏验证性实验的数值模拟,重点探究了干燥收缩变形对结构裂缝演化和破坏模式的影响规律.分析结果表明:该模型合理地反映了多场耦合和多重变形竞争机制,因此能够更加准确地预测早龄期混凝土结构的裂缝演化过程和最终破坏模式,对实际混凝土结构建造期的裂缝模拟、损伤破坏分析以及全生命周期服役安全评估具有指导意义.Early-age cracking in concrete has been one of the most commonly encountered and challenging problems in massive concrete structures such as nuclear containment,tunnels and bridges,hydraulic dams and so on,severely threatening the integrity,durability and safety of such structures.This is due to the fact that early-age concrete is affected by complex multi-physics coupling processes,e.g.,cement hydration,heat transfer,moisture transport and mechanical loading,etc.The resulting multi-deformation competition among autogenous shrinkage,thermal expansion/contraction,drying shrinkage,and load induced deformations,etc.,leading to early-age cracking in concrete structures during the construction period.Within the framework of the unified phase-field theory for damage and fracture in solids,a chemothermo-hygro-mechanically coupled phase-field cohesive zone model(PF-CZM)is established in this work,with the multi-physics coupling and the resulting multi-deformation competition incorporated rationally.The proposed model is then applied to several representative benchmark tests of early-age concrete specimens.The cracking induced failure process is quantitatively studied,focusing on the influences of the drying shrinkage on the crack evolution and failure mode.The numerical results show that,the proposed chemo-thermo-hygro-mechanically coupled PF-CZM is able to capture rationally the multi-physics coupling and multi-deformation competition during cracking in early-age concrete such that the failure process of structures can be well predicted.This feature makes it be used in prediction of cracking induced failure during the construction period and in assessment of structural safety during the service life-cycle of practical engineering structures.

关 键 词：混凝土 早龄期裂缝 多场 统一相场理论 干燥收缩 

分 类 号：O346.1[理学—固体力学] O346.5[理学—力学] TU311.4[建筑科学—结构工程]