沥青路面结构的模量取值研究

发布时间：2018-01-10 13:31

本文关键词：沥青路面结构的模量取值研究　出处：《武汉工程大学》2014年硕士论文　论文类型：学位论文

【摘要】：现行的路面结构设计方法中，沥青路面结构分析计算过程中的重要参数是沥青混合料的劲度，劲度可以采用静态蠕变模量或动态模量表示。然而，采用静态蠕变模量或动态模量表示沥青路面行车状态下的劲度模量并不全面。已有的研究成果表明，，使用动态回弹模量表征沥青路面结构的劲度模量显得更为合理。动态模量和动态回弹模量均可以通过实验的方法获得，但室内试验准确的获取动态模量需要施加准确的波形力，如何获取准确的实验室加载波形便是首要解决的问题。动态模量与动态回弹模量的室内实验获取方法的主要差别在于：动态模量施加连续周期荷载，周期间不考虑休息时间；而动态回弹模量施加的荷载周期之间存在休息时间。不管是动态模量试验还是动态回弹模量试验，加载波形都是车辆荷载作用下沥青路面结构中沥青层内的应力脉冲波形的拟合。目前，AASHTO试验方法中动态模量试验是通过采用半正弦波加载方式获取，这与实际情况有一定的偏差。行车荷载下不同深度处的竖向应力脉冲波形并不相同，波长也不相同。其准确性依赖于合理的轮胎接地压力和计算模型。本文首先分别利用ANSYS和BISAR建立的计算模型，对比路面结构内沥青层的竖向应力，验证ANSYS所建立的三维有限元计算模型的可靠性；其次，利用三维有限元计算工具，结合实测的竖向轮胎-路面接地压力并考虑水平作用力，考虑沥青路面结构层不同的模量和厚度组合，计算沥青路面结构层不同深度处的竖向应力，得到不同位置的竖向应力脉冲波形，推导相应的波长和荷载作用时间的计算公式。依据上述分析得到的沥青路面结构层不同深度处的竖向应力脉冲波形，利用不同的函数形式，对这些应力脉冲波形进行拟合。最后，结合已有的加载周期休息时间，进行室内试验，比较动态模量和动态回弹模量的差异。
[Abstract]:In the current design method of pavement structure, the stiffness of asphalt mixture can be expressed as static creep modulus or dynamic modulus, which is an important parameter in the analysis and calculation of asphalt pavement structure. Using static creep modulus or dynamic modulus to express the stiffness modulus of asphalt pavement is not comprehensive. It is more reasonable to use dynamic elastic modulus to characterize the stiffness modulus of asphalt pavement structure. Both dynamic modulus and dynamic modulus of resilience can be obtained by experimental method. However, it is necessary to apply accurate waveform force to obtain dynamic modulus accurately in laboratory test, and how to obtain accurate loading waveform in laboratory is the first problem to be solved. The main difference between the dynamic modulus and the dynamic elastic modulus is that the dynamic modulus exerts continuous periodic load, and the rest time is not considered during the week; However, there is a rest time between the load periods under dynamic modulus of springback, whether it is dynamic modulus test or dynamic springback modulus test. The loading waveform is the fitting of the stress pulse waveform in the asphalt pavement structure under the vehicle load. The dynamic modulus test in AASHTO test method is obtained by semi-sine wave loading, which is different from the actual situation. The vertical stress pulse waveform at different depth is not the same. The accuracy depends on reasonable tire grounding pressure and calculation model. In this paper, the calculation models established by ANSYS and BISAR are used to compare the vertical stress of asphalt layer in pavement structure, and the reliability of the three-dimensional finite element model established by ANSYS is verified. Secondly, using three-dimensional finite element calculation tool, combined with the measured vertical tire-road ground pressure and considering the horizontal force, considering the asphalt pavement structure layer of different modulus and thickness combination. The vertical stress at different depth of asphalt pavement structure layer is calculated and the pulse waveform of vertical stress is obtained at different positions. According to the above analysis, the vertical stress pulse waveforms at different depths of asphalt pavement layer are obtained, and different function forms are used. These stress pulse waveforms are fitted. Finally, the difference between dynamic modulus and dynamic modulus of springback is compared by indoor test combined with the rest time of the existing loading cycle.
【学位授予单位】：武汉工程大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U416.217

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