路基平衡湿度气候响应机制及其基于时域反射原理的测试数据解析优化

Quantitative impact of external environment on subgrade moisture and fine characterization methods for moisture equilibria is one of the key elements for theory of pavement analysis and design. Technical means has been adopted to the research program, such as field survey and test, laboratory experiments, numerical simulation and theoretical analysis along with the trend of mechanism of influencing factors and automation of testing technique for study on subgrade moisture. First, systemic physical expression of subgrade moisture has been studied, including definition of design state, migration mechanism of water in subgrade and new criteria of classification for humidity type of subgrade. Secondly, distribution characteristics and presentation of moisture has been proposed in time or Spatial dimension under the law of moisture variation. Furthermore, establishment of response model has been given according to association analysis of environmental factors. Finally, test data from TDR has been resolved based on system identification, transmission line equation and volume theory of composite materials. Resolution program has contained calibration of parameters of electromagnetic properties and moisture content. Comparison between existing algorithms and proposed optimization algorithm has been made to validate improvement of the latter. The research results as mentioned above have great theoretical significance and practical prospect with scientific basis for the reseach of pavement structural mechanics or road performance evaluation and theoretical support for the revision of pavement design specification.

道路路基湿度状态受气候条件等外界环境因素影响显著，针对路基湿度研究呈现影响因素机理化、测试技术自动化的趋势，本项目拟采取现场调研与测试、室内试验、数值模拟、理论分析等技术手段，明确应以平衡湿度作为路基湿度设计状态，在此基础上揭示路基水的作用机理，提出路基湿度类型划分新标准；根据路基湿度变化规律，阐明路基湿度在时空维度上的分布特征并给出表述方式，对路基湿度环境影响因素进行关联分析并建立环境响应模型；基于系统识别思想，采用传输线方程与体积混合理论，对TDR测试数据进行解析，包括介电常数、反射系数、电导率等电磁特性参数与含水率指标的校正，并利用现场测试数据对已有算法与本项目提出的优化算法进行比较分析。研究成果可拓展工程结构物工作状态外界环境定量影响研究的思路，也可为路面结构力学分析以及道路使用性能评价提供科学依据，具有重要的学术意义和实用前景。

针对路基湿度状态影响因素与类型划分、平衡湿度预估等内容开展了系统、深入的研究。通过广泛的国内外文献资料调研，并结合全国范围十条不同等级公路十多个路段路基湿度状态的现场调研，明确沥青路面结构设计中，应以平衡湿度作为路基湿度设计状态。综合路基湿度各种影响因素，可将其归并为气候与地下水位两大主要控制因素，并据此划分路基湿度类型为干燥、中湿和潮湿三类。为计算反映气候因素的指标—湿度指数（TMI），根据收集到的全国上百个气象站点数据，计算获得各个站点对应的TMI值，并按公路自然区划进行归并，得到不同自然区划、不同土组的TMI值的范围与均值。建立两种模型预估路基湿度—适合干燥类路基的TMI模型与适合潮湿类路基的地下水位模型，进一步，提出我国不同湿度类型与区划条件下典型土组路基平衡湿度推荐值。