基于细观尺度的钢桥面铺装界面行为特性与抗裂机理研究

Macro-interfacial fracture test model of composite pavement structure was provided for the first time in the youth fund, and the criteria were deduced to decide whether the interface was in integral state or in contact-slip state. After then, the partial interaction model of composite beam was developed and contact parameters were back calculated based on both theoretical analysis and experiment study. An innovative test method for pavement damping was established for the first time to represent vibration characteristics more accurately. Furthermore, the multi-level 3D simulation model including macro-interfacial features was developed. Based on it, the both e material design and deck system structural design were achieved. In this proposal, both the discrete element and boundary element are introduced in this project to establish mesostructural model, which can simulate pavement and bonding interface behavior well. Then the composite structural test models will be developed to indicate the real mechanic state of the bonding interface between pavement and steel deck. With the aid of X-ray CT and high-precise video recorder, the tests are monitored and the images are processed and analyzed to obtain the characteristics of the singularity field. From the meso-level view, the crack initiating threshold is deduced, micro crack propagation law and macro-fracture militarism are linked to modify the ellipse damage criteria. Furthermore, multi-scale simulation model including the mesostructure and macrostructure is developed to reveal the coupling effect mechanism between the pavement crack and interfacial crack. Finally, the auti-crack indexes are derived for steel deck pavement.

青年基金首次建立了界面端断裂宏观试验模型，通过粘结界面裂纹沿界面破坏的断裂实验确定由粘结状态向接触-滑移状态转移的判据。建立基于粘结界面接触-滑移特性的铺装复合梁理论模型，通过理论分析和试验研究得到了界面接触滑移本构参数。首次提出了铺装材料阻尼测试方法，准确地反映了铺装振动特性。构建包含宏观界面特性的多尺度三维仿真模型，研究了铺装材料、桥面系结构的优化方法。本项目拟同时引入离散元和界面元，构建能准确模拟铺装混凝土结构、粘结界面行为特性的细观仿真模型；开发反映铺装粘结界面真实受力状态的复合结构细观试验模型，采用X-ray CT和高精度图像监控技术，从细观机理层面推演铺装粘结界面端奇异场特性参数，确定界面启裂的门槛值，建立细观裂纹萌生扩展规律与宏观裂缝失效行为的联系，完善青年基金提出的椭圆破坏准则；建立宏、细观结合的跨尺度仿真模型，真实地揭示铺装裂缝和界面裂缝耦合作用机理，形成综合抗裂指标。

铺装沥青混凝土与钢桥面板的粘结界面对钢桥面铺装结构的协同变形至关重要，鉴于铺装层是复杂的多相非均质复合材料，本研究从细观层次入手，研究钢桥面铺装界面行为特性，进而深入探究宏细观之间的联系，揭示界面抗裂机理，对钢桥面铺装体系的力学性能研究和优化设计具有重要的理论意义和应用价值。.考虑非均质、多相和多尺度等因素，采用数字图像处理技术重构能够反映铺装材料真实结构的细观骨架，并解决了边缘锯齿、颗粒连接、形态特征简化等技术难题；采用Voronoi随机生成技术能够反映各种形态及不同分布特征的颗粒，进而构建铺装材料细观骨架，形成了能够有效克服CPU耗费大、骨料投放含量偏低的三维虚拟模型生成关键技术。进一步建立混凝土内部结构特征参数与温度场分布特点之间的关系，提出混凝土有效导热系数的理论计算方法，以用于校验有限元温度场分析结果的可靠性。.从界面破坏特性、尺度和界面缺陷三个方面分析钢桥面粘结层界面力学行为，探究粘结层与铺装混凝土相互作用的细观机理，并揭示其与粘结界面几何形态及粘结强度的内在联系，进而提出钢桥面铺装细观结构模式及其判定方法。.提出了局部布设粘聚单元的算法，采用粘聚力模型、粘弹性本构模型和线弹性本构模型分别描述各细观相的开裂行为、沥青砂浆的粘弹性行为、集料和钢板的线弹性行为，实现钢桥面铺装混合料细观异质断裂模型的构建。.基于自主研发的可变角度压剪试验测试装置设计多角度斜压（剪）试验，采用高精度图像监控技术和数值图像分析技术还原试件表面位移场并校正细观异质断裂模型。基于此，讨论分析斜拉（剪）和斜压（剪）工况下钢桥面铺装界面启裂扩展细观行为特性，建立细观裂纹萌生扩展规律与宏观裂缝失效行为之间的联系，进一步给出了以粘结层断裂参数和受力方向为双重判据的铺装粘结界面破坏准则，包括8种典型断裂形式以及6阶段断裂演化过程。.将局部细观尺度模型和宏观钢桥面铺装体系纳入整体结构考虑，建立钢桥面铺装体系跨尺度仿真模型，揭示铺装裂缝和界面裂缝相互作用机理，优化了细观界面参数。