【作者】 张旭；

【导师】 张蓓；

【作者基本信息】 郑州大学 ， 岩土工程， 2021， 硕士

【摘要】 目前,我国现行的公路设计理论和性能评价方法多以静载作用下的路面结构作为研究对象。但是,行驶中的车辆对路面的作用通常是一种大小与位置都随时间不断变化的动荷载,这导致现行的公路设计理论和性能评价方法不能完全适用于我国沥青路面的性能评价。随着落锤式弯沉仪(Falling Weight Deflectometer,FWD)的广泛使用,如何建立FWD冲击荷载下的沥青路面动力响应模型,根据FWD弯沉盆数据进行路面结构层模量反演已经成为目前国内外沥青路面性能评价的研究热点。同时,随着季节气候变化,路面结构内部温度会随之发生较大变化,对于温度敏感性较强的沥青混合料,温度变化会对其力学特性产生影响,进而影响路面结构承载性和稳定性。鉴于上述情况,本文开展了考虑温度影响的半刚性基层沥青路面动力响应及反演研究。研究成果对路面结构的动态设计以及性能评价具有理论指导意义。本文主要工作如下:(1)基于谱元法基本理论,对半刚性基层沥青路面结构的动力响应进行了分析,并编写了半刚性基层路面动力响应计算程序。将计算结果与ABAQUS数值分析和实测弯沉结果进行了对比分析,结果表明:本文的计算结果具有较高的精度,并且相较于有限元法,谱元法的计算效率得到了有效的提高。在此基础上,系统研究了半刚性基层路面结构模量和厚度对路面弯沉的影响规律。(2)考虑在温度的影响下,沥青面层材料模量具有非均质梯度特性,采用谱元法建立了 FWD荷载作用下面层模量随温度梯度变化的力学模型,分析了路面弯沉的季节变化规律及日变化规律,并和传统等温模型的弯沉计算结果进行了对比分析。在此基础上,建立了适用于半刚性基层路面弯沉的温度修正公式。(3)基于改进麻雀搜索算法(ISSA)优化了最小二乘支持向量机模型(LSSVM)参数和路面模量的选取,提出了基于ISSA-LSSVM的路面结构层模量动力反演方法,并编写了路面模量动力反演程序。通过算例和工程实例的计算结果证明了本文反演方法具有较高的精度,并且相较于原始麻雀搜索算法,改进麻雀搜索算法的反演精度得到了提高。在此基础上,对路面结构层反演模量进行了敏感度分析,并考虑温度对面层反演模量影响,提出了根据面层模量温度修正系数对面层反演模量进行温度修正的方法。更多还原

【Abstract】 At present the current road design theories and performance evaluation methods in our country mostly take the pavement structure under static load as the research object.However,the effect of the driving vehicle on the pavement is usually a dynamic load whose size and position are constantly changing over time,which causes the current highway design theory and performance evaluation method to not be fully applicable to the performance evaluation of asphalt pavement in my country.With the widespread use of Falling Weight Deflectometer(FWD),how to establish the dynamic response model of asphalt pavement under FWD impact load,and the inversion of pavement structure layer modulus based on FWD deflection basin data has become a reality at home and abroad.Research hotspots of asphalt pavement performance evaluation.At the same time,as the seasonal climate changes,the internal temperature of the pavement structure will change significantly.For the temperature-sensitive asphalt mixture,the temperature change will affect its mechanical properties,and then affect the bearing capacity and stability of the pavement structure.In view of the above situation,this paper has carried out the research on the dynamic response and back analysis of the semi-rigid base asphalt pavement considering the influence of temperature.The research results have theoretical guiding significance for the dynamic design and performance evaluation of pavement structure.The main work of this paper is as follows:(1)Based on the basic theory of spectrum element method,the dynamic response of semi-rigid base asphalt pavement structure is analyzed,and the dynamic response calculation program of semi-rigid base pavement is compiled.The calculation results are compared with the ABAQUS numerical analysis and the measured deflection results.The results show that the calculation results in this paper have higher accuracy,and compared with the finite element method,the calculation efficiency of the spectral element method has been effectively improved.On this basis,the influence law of semi-rigid base pavement structure modulus and thickness on pavement deflection was systematically studied.(2)Considering that under the influence of temperature,the material modulus of the asphalt surface course has a heterogeneous gradient characteristic,the spectral element method is used to establish the mechanical model of the change of the lower layer modulus with the temperature gradient under the FWD load,and the seasonal variation of the road surface deflection is analyzed.And the diurnal variation rules,and compared with the deflection calculation results of the traditional isothermal model.On this basis,a temperature correction formula suitable for semi-rigid base pavement deflection is established.(3)Based on the improved sparrow search algorithm(ISSA),the least squares support vector machine model(LSSVM)parameters and the selection of pavement modulus are optimized,and the dynamic inversion method of pavement structure layer modulus based on ISSA-LSSVM is proposed,and the pavement model is compiled.Quantitative dynamic inversion procedure.The calculation results of calculation examples and engineering examples prove that the inversion method in this paper has higher accuracy,and compared with the original sparrow search algorithm,the inversion accuracy of the improved sparrow search algorithm has been improved.On this basis,the sensitivity analysis of the inversion modulus of the pavement structure layer was carried out,and the influence of temperature on the inversion modulus of the surface layer was considered,and a temperature correction method for the inversion modulus of the surface layer based on the temperature correction coefficient of the surface layer modulus was proposed method.更多还原