复杂行驶工况下考虑沥青路面变温粘弹性的动态轴载换算

发布时间：2018-01-14 04:14

本文关键词：复杂行驶工况下考虑沥青路面变温粘弹性的动态轴载换算　出处：《合肥工业大学》2015年硕士论文　论文类型：学位论文

【摘要】：现有的沥青路面结构设计将车辆荷载假定为双圆均布静态荷载,忽略了车辆荷载的动态行为和沥青混凝土的粘弹性特征。现行的城镇道路设计规范虽然将沥青层剪应力作为设计指标,但仍借用公路设计规范中沥青路面弯沉和层底弯拉应力的轴载换算公式,这种方法存在不足。因此,本文建立了刚性基层沥青路面三维数值模型,考虑路面温度场对沥青混凝土粘弹性参数的影响,研究移动荷载对沥青路面动力学响应的影响,根据弯拉应力和剪应力指标分别提出了相应的动态轴载换算公式。首先,基于二维Lamb问题对数值仿真的有效性进行验证,并对阻尼参数的设定做了比选。建立双圆均布移动荷载作用下的刚性基层沥青路面数值模型,综合分析了荷载移动速度、路面摩擦系数和轴载对路面结构动力响应的影响,获得以沥青层底弯拉应力为指标并考虑路面摩擦系数的动态轴载换算公式。其次,进行沥青路面温度场仿真的有效性验证。开展刚性基层沥青路面的温度测量实验,并建立相同工况的数值模型进行温度场仿真,使用检测数据对仿真结果进行了验证,证明了数值分析方法有效可行,计算结果可以为第五章进行沥青材料变温粘弹性分析提供有效的温度场数据。再次,建立轮胎-路面结构的三维数值模型。由于轮胎结构十分复杂,所以本文对轮胎结构进行了适当简化,并利用Hypermesh和AutoCAD软件建立子午线轮胎的三维模型。结合温度场仿真数据,通过VUMAT用户子程序将路面结构的沥青混凝土粘弹性参数定义为温度的函数,将轮胎模型导入ABAQUS中与路面结构组成轮胎-路面三维数值模型。最后,车辆分别采用不同的加速度和减速度,进行非匀速移动荷载作用下沥青路面的动力响应分析。结合交叉口车辆启动和制动车速实验,在考虑沥青混凝土变温粘弹性的情况下进行沥青路面动力响应数值分析,根据计算结果提出基于刚性基层沥青路面沥青层剪应力的动态轴载换算公式,弥补了当前城镇道路设计规范未单独提出以沥青层剪应力进行轴载换算的不足。
[Abstract]:The existing asphalt pavement structure design assumes the vehicle load as double circular uniform static load. The dynamic behavior of vehicle load and the viscoelastic characteristics of asphalt concrete are ignored. Although the shear stress of asphalt layer is taken as the design index in the current design code for urban roads. However, the axial load conversion formula of asphalt pavement deflection and bottom bending stress is still used in the highway design code. This method has some shortcomings. Therefore, a three-dimensional numerical model of rigid base asphalt pavement is established in this paper. Considering the influence of pavement temperature field on the viscoelastic parameters of asphalt concrete, the effect of moving load on the dynamic response of asphalt pavement is studied. According to the flexural stress and shear stress index, the corresponding dynamic axial load conversion formulas are proposed. Firstly, the validity of the numerical simulation is verified based on the two-dimensional Lamb problem. The numerical model of rigid base asphalt pavement under the action of double circular uniform moving load is established, and the load moving speed is analyzed synthetically. The influence of pavement friction coefficient and axle load on the dynamic response of pavement structure, the dynamic axial load conversion formula is obtained, which takes the bending and tensile stress of asphalt bottom as the index and considers the pavement friction coefficient. Secondly. The validity of temperature field simulation of asphalt pavement is verified. The temperature measurement experiment of asphalt pavement with rigid base is carried out, and the numerical model of the same working condition is established to simulate the temperature field. The simulation results are verified by the test data, and the results show that the numerical analysis method is effective and feasible. The calculated results can provide the effective temperature field data for the 5th chapter of the asphalt material variable temperature viscoelastic analysis. The three-dimensional numerical model of tire pavement structure is established. Because the tire structure is very complex, the tire structure is simplified in this paper. The three-dimensional model of radial tire is built by using Hypermesh and AutoCAD software, and the simulation data of temperature field are combined. The viscoelastic parameters of asphalt concrete of pavement structure are defined as a function of temperature by VUMAT user subroutine. The tire model is introduced into ABAQUS to form a three-dimensional numerical model of tire and road surface. Finally, the vehicle adopts different acceleration and deceleration. The dynamic response of asphalt pavement under non-uniform moving load is analyzed. Considering the variable temperature viscoelasticity of asphalt concrete, the dynamic response of asphalt pavement is analyzed numerically. Based on the calculation results, the dynamic axial load conversion formula based on the shear stress of asphalt layer of rigid base asphalt pavement is proposed. It makes up for the deficiency that the shearing stress of asphalt layer is not used separately in the current urban road design code.
【学位授予单位】：合肥工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U416.217

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