沥青路面荷载应力-渗流-损伤多场耦合效应

Under traffic load and hydrodynamic pressure, asphalt mixture and pavement structure are in continuous development and evolution with degradation and deterioration, thus showing the multi-fields coupling effect of load stress-seepage-damage. The project based on the theory and method of fluid mechanics, porous media mechanics, thermodynamics and fatigue damage mechanics, carry out different tests (including permeability test, seepage flow test, compression or tensile test, fatigue test) under different load and temperature condition，using the computerized tomography technology, optical tracking and digital image processing technique and nonlinear finite element simulation analysis. The permeability of asphalt mixture, the law of seepage flow in asphalt pavement, the stress-strain relationship and fatigue damage performance of saturated asphalt mixture are researched systematically. Then the effects of load, temperature, gradation and porosity of aggregate, damage, surface layer structure type on them are compared and analyzed. This disserta tion proposes asphalt pavement percolation theory, the constitutive relation of multi-fields of load stress-seepage-damage and fatigue damage evolution rule for asphalt mixture, so to establish the constitutive theory system of the multi-fields of load stress-seepage-damage for asphalt mixture. Finally, the mechanism of asphalt pavement water-induced damage causing by the multi-fields coupling effect of load stress-seepage-damage for asphalt pavement is revealed according to the fatigue damage numerical simulation of saturated asphalt pavement and the fatigue test of simulating pavement structure.

在交通荷载和动水压力作用下，沥青混合料及其路面结构处于不断损伤劣化演变过程，呈现出荷载应力-渗流-损伤多场耦合行为。项目根据流体力学、多孔介质力学、热力学、疲劳损伤力学等理论与方法，通过不同荷载、温度条件下的渗透、渗流、压缩或拉伸、疲劳等试验，结合计算机断层扫描、光学跟踪和数字图像处理等技术，以及非线性有限元模拟计算，系统地研究沥青混合料渗透特性、沥青面层结构的渗流规律、饱水沥青混合料应力应变规律以及疲劳损伤演化规律，对比分析荷载、温度、级配、孔隙率、损伤、面层结构组合类型等因素对它们的影响，提出沥青面层渗流理论、沥青混合料荷载应力-渗流-损伤多场耦合本构关系及其疲劳损伤演化方程，从而构建沥青混合料荷载应力-渗流-损伤多场耦合本构理论体系。并通过饱水沥青路面结构的疲劳损伤数值模拟计算和模拟结构的疲劳试验研究，提出基于荷载应力-渗流-损伤多场耦合效应的沥青路面水损害机理。

本项目针对沥青路面水损害，通过荷载-损伤-渗流多场耦合条件下路面材料渗透性测试系统、动水冲刷试验仪和结构渗流模拟试验装置及其试验方法的研发与应用，结合多场耦合条件下疲劳加载时沥青混合料细观结构测试和沥青路面流固耦合效应的非线性有限元分析，系统深入地研究了沥青混合料及其结构在不同条件下水稳定性、渗透特性、渗流规律及疲劳损伤特性。对比分析了级配、公称最大粒径、空隙率、成型方式、疲劳加载、轴压、围压、水压、环境温度等因素对沥青混合料渗透性能的影响规律。探讨了沥青混合料非线性渗流特性，提出了一种沥青混合料非线性渗流模型及沥青路面中达西渗流适用的临界条件。系统地模拟分析了结构参数、荷载参数、沥青混合料渗流特性参数等因素对沥青路面结构流固耦合效应的影响规律。基于沥青混合料随疲劳加载过程细观空隙特征的变化，建立了荷载-渗流耦合条件下沥青混合料的疲劳损伤演化方程，提出了损伤-渗流耦合条件下沥青混合料的渗透性演化规律（三种演化模式），以及疲劳加载影响沥青混合料渗透性的作用机制，进一步揭示了沥青路面水损害机理。为科学地评价沥青混合料及其路面结构水稳定性、抗水损害结构设计、防排水设计和水稳定性改善等一系列工作，提供了有益的理论和试验基础。