沥青路面半刚性基层材料与结构疲劳损伤研究
发布时间：2019-01-03 18:56
【摘要】：沥青路面半刚性基层疲劳预估模型一直沿用的单一疲劳指标模式，不能适应重载和气候环境综合作用下半刚性基层沥青路面结构性能评价的要求。半刚性基层沥青路面急需突破长寿命路面结构设计的技术瓶颈，主要是结构性能评价中反映实际状态的疲劳损伤模型及其支持参数。其建立方法和应用是半刚性基层沥青路面的共性关键技术。 本文通过理论与实验研究，改进了半刚性材料室内疲劳损伤测试方法，提出了用弯拉模量衰减率和弯拉强度比两项指标联合表征的半刚性材料疲劳损伤模型，基于室内ALF加速加载试验和现场实体工程观测验证，得出了反映路面结构实际损伤状态的半刚性基层结构疲劳损伤模型及其支撑参数。 针对现行半刚性材料疲劳试验结果离散性和变异性大的技术难题，通过对比试验分析，提出了用同层位梁试件弯拉强度确定疲劳荷载的疲劳损伤测试方法，提高了试验结果的可靠性；针对重复加载致梁体沿长度方向模量不均匀的问题，，提出了测量梁试件中段1/3区域挠度差的重复加载弯拉模量测试方法，实现半刚性材料不同疲劳损伤程度弯拉模量的测试；基于重复加载疲劳试验和连续损伤力学原理，首次建立了用弯拉模量衰减指标和疲劳方程联合表征的半刚性材料疲劳损伤模型；为解决支撑疲劳损伤模型力学响应计算的结构模量参数取值问题，通过对不同试验理论与方法测试比较，提出了基于试件中段应变测量的半刚性材料单轴压缩弹性模量简单试验方法，提高了模量测试结果的可靠性，解决了现行试验方法模量参数与实际不符的技术难题；基于理论与现场检测验证，提出了半刚性材料层设计期末疲劳损伤状态下的有效模量确定方法，为结构损伤全过程分析参数输入提供依据；开发了适用于半刚性材料与结构在现场环境作用下的响应测试新技术，首次得到了半刚性基层结构现场温度变化引起的应力应变响应特征；首次综合重载ALF加速加载试验路与路面力学响应传感测试系统对半刚性基层疲劳损伤模型进行观测验证，明确了半刚性基层结构损伤演变过程及不同阶段的状态，提出了疲劳开裂产生阶段与裂缝扩展阶段时长的关系。
[Abstract]:The single fatigue index model of semi-rigid base asphalt pavement used all the time can not meet the requirements of structural performance evaluation of semi-rigid base asphalt pavement under the combined action of heavy load and climate environment. It is urgent for semi-rigid base asphalt pavement to break through the technical bottleneck of structural design of long-life pavement, which is mainly the fatigue damage model and its supporting parameters which reflect the actual state in structural performance evaluation. Its establishment method and application are the common key technology of semi-rigid base asphalt pavement. Based on the theoretical and experimental studies, this paper improves the indoor fatigue damage test method of semi-rigid materials, and presents a fatigue damage model of semi-rigid materials, which is characterized by the attenuation rate of flexural modulus and the ratio of flexural strength to tensile strength. Based on indoor ALF accelerated loading test and field engineering observation, the fatigue damage model of semi-rigid base structure and its supporting parameters are obtained to reflect the actual damage state of pavement structure. In view of the technical problems of discrete and high variability of fatigue test results of semi-rigid materials, a fatigue damage test method based on bending and tensile strength of specimens of the same layer beam is put forward through comparative test analysis. The reliability of the test results is improved. In order to solve the problem that the modulus of beam is not uniform in the direction of length caused by repeated loading, a method for measuring the deflection difference of 1 / 3 region in the middle section of beam specimen by repeated loading is put forward. The flexural modulus of semi-rigid material with different fatigue damage degree is tested. Based on the repeated loading fatigue test and the principle of continuous damage mechanics, the fatigue damage model of semi-rigid materials is first established, which is characterized by bending modulus attenuation index and fatigue equation. In order to solve the problem of determining the structural modulus parameters in the mechanical response calculation of the fatigue damage model of brace, the different test theories and methods are compared. A simple test method for uniaxial compression elastic modulus of semi-rigid materials based on mid-section strain measurement is proposed, which improves the reliability of the test results and solves the technical problem that the modulus parameters of the current test methods are not in accordance with the actual conditions. Based on the verification of theory and field test, a method for determining effective modulus of semi-rigid material layer under fatigue damage state at the end of design period is proposed, which provides the basis for the input of parameters in the whole process of structural damage analysis. A new response test technique for semi-rigid materials and structures under the action of field environment is developed, and the stress-strain response characteristics of semi-rigid base structure caused by field temperature change are obtained for the first time. For the first time, the fatigue damage model of semi-rigid base is observed and verified by the ALF accelerated loading test road and the pavement mechanical response sensing system, and the damage evolution process and the state of the semi-rigid base structure in different stages are clarified. The relationship between fatigue crack generation stage and crack propagation stage is put forward.
【学位授予单位】：长安大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：U416.217
本文编号：2399756
[Abstract]:The single fatigue index model of semi-rigid base asphalt pavement used all the time can not meet the requirements of structural performance evaluation of semi-rigid base asphalt pavement under the combined action of heavy load and climate environment. It is urgent for semi-rigid base asphalt pavement to break through the technical bottleneck of structural design of long-life pavement, which is mainly the fatigue damage model and its supporting parameters which reflect the actual state in structural performance evaluation. Its establishment method and application are the common key technology of semi-rigid base asphalt pavement. Based on the theoretical and experimental studies, this paper improves the indoor fatigue damage test method of semi-rigid materials, and presents a fatigue damage model of semi-rigid materials, which is characterized by the attenuation rate of flexural modulus and the ratio of flexural strength to tensile strength. Based on indoor ALF accelerated loading test and field engineering observation, the fatigue damage model of semi-rigid base structure and its supporting parameters are obtained to reflect the actual damage state of pavement structure. In view of the technical problems of discrete and high variability of fatigue test results of semi-rigid materials, a fatigue damage test method based on bending and tensile strength of specimens of the same layer beam is put forward through comparative test analysis. The reliability of the test results is improved. In order to solve the problem that the modulus of beam is not uniform in the direction of length caused by repeated loading, a method for measuring the deflection difference of 1 / 3 region in the middle section of beam specimen by repeated loading is put forward. The flexural modulus of semi-rigid material with different fatigue damage degree is tested. Based on the repeated loading fatigue test and the principle of continuous damage mechanics, the fatigue damage model of semi-rigid materials is first established, which is characterized by bending modulus attenuation index and fatigue equation. In order to solve the problem of determining the structural modulus parameters in the mechanical response calculation of the fatigue damage model of brace, the different test theories and methods are compared. A simple test method for uniaxial compression elastic modulus of semi-rigid materials based on mid-section strain measurement is proposed, which improves the reliability of the test results and solves the technical problem that the modulus parameters of the current test methods are not in accordance with the actual conditions. Based on the verification of theory and field test, a method for determining effective modulus of semi-rigid material layer under fatigue damage state at the end of design period is proposed, which provides the basis for the input of parameters in the whole process of structural damage analysis. A new response test technique for semi-rigid materials and structures under the action of field environment is developed, and the stress-strain response characteristics of semi-rigid base structure caused by field temperature change are obtained for the first time. For the first time, the fatigue damage model of semi-rigid base is observed and verified by the ALF accelerated loading test road and the pavement mechanical response sensing system, and the damage evolution process and the state of the semi-rigid base structure in different stages are clarified. The relationship between fatigue crack generation stage and crack propagation stage is put forward.
【学位授予单位】：长安大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：U416.217
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