公路路基结构动力响应的拟静力学分析方法

Dynamic operation of the vehicle influences long-term stability of subgrade structure, it is one of the key problems to enhance the level of the road construction by obtaining the evolution mechanism of the subgrade properties under traffic load in our country. This paper will study the distribution law of dynamic response in subgrade and its analysis methods through the laboratory test, theoretical analysis, numerical calculation and field test:Through the field and laboratory test, the calculation parameters of the vehicles , roughness of the pavement and each layer of the subgrade are determined. Indoor static resilience modulus and dynamic triaxial compression test are done, the equivalent relationship between the static and dynamic resilient modulus is got.The theoretical analysis is done, the static analysis model and the coupled dynamic analysis model of vehicle system – unevenness pavement - subgrade are built. On-site mechanical response test of the subgrade is done, the static and dynamic model are modified according to the test results, and based on the models the numerical calculation is done, the distribution law of the static and dynamic response of the subgrade in the typical work cases is studied, the equivalent expression of static and dynamic stress is built, and on the basis of the field test results, the expression is modified. At last,the quasi-statics mechanical analysis method of the dynamic response of subgrade is raised to provide theoretical basis and technical support for the structural design of highway subgrade.

车辆运行产生的动力作用影响着公路路基结构的长期稳定，准确获取交通荷载作用下路基力学性能演变机制是提升我国公路建设水平的关键难题之一。本课题将通过室内试验、理论分析、数值计算及现场测试等方法对路基动力响应分布规律及其分析方法展开深入研究：通过现场测试及室内试验，确定依托工程车辆、路面平整度及公路各结构层计算参数；进行室内静回弹模量及动三轴实验，建立路基填土静、动回弹模量等效关系；通过理论分析，分别建立路基结构的静力分析模型以及车辆系统—不平整路面—路基耦合动力分析模型；开展现场路基力学响应测试，依据测试结果对静、动力模型进行修正，并据此进行数值计算，获取典型工况下路基静、动力响应分布规律，建立路基静、动应力的等效关系表达式，并依据现场实测结果对其进行修正，最终给出公路路基结构动力响应的拟静力学分析方法，为我国公路路基的结构设计提供理论依据和技术支持。

本项目针对目前公路路基路面结构设计方面的不足，通过系统的理论分析和试验研究，建立了简便、准确且适合于工程应用的路基结构动力响应的拟静力学分析方法。首先进行依托工程典型路段的现场调研以及现场路面平整度测试，并利用谱分析方法获得现场路面不平整波长、幅值以及相关路面参数。并以此为依据为室内动三轴试验提供参数。其次，进行了土工试验，获得土样的基本物理参数，开展了原状土的静、动三轴试验，得到了土样的强度参数，分析了循环次数、动应力幅值、围压、初始静偏应力、波形和振动频率对饱和土的动力特性影响规律。然后，根据车辆行驶特点，考虑路基、路面的协调作用，将路面的不平整高低起伏假设为正弦变化，路面材料假设为线弹性体，引入车辆及道路系统的微分方程，建立车辆体系—不平整路面—路基耦合动力分析模型。最后，根据耦合模型进行多种典型工况下的路基静、动应力计算分析，得到路基静、动应力分布规律。将得到的路基静、动应力分布状况进行对比，绘制路基填土静、动应力的变化曲线，建立了路基静、动应力分布的等效关系表达式。对比现场实测结果，验证了等效关系表达式的合理性，提出了交通荷载作用下公路路基动力响应的拟静力学分析方法，为我国公路建设提供了理论依据和技术支持。