非均布垂直轮载作用下柔性基层沥青路面结构力学行为研究

发布时间：2018-01-15 03:22

本文关键词：非均布垂直轮载作用下柔性基层沥青路面结构力学行为研究　出处：《西南交通大学》2015年硕士论文　论文类型：学位论文

【摘要】：随着发达国家柔性基层沥青路面的发展,结合自身国情与环境,我国相关机构逐渐将该类路面结构形式应用于高等级公路中。目前国内外沥青路面设计规范大多采用圆形均布荷载模拟车辆对路面结构的作用力,且假定各结构层间完全连续。然而,轮胎接地压力分布规律极其复杂,其接触面形状也并非圆形,而是接近于椭圆形、矩形,其作用力更是表现出明显的非均匀性,且沥青路面各结构层材料性质、施工工序、施工质量控制存在一定差异,导致层间粘结较为薄弱,无法达到理想的完全连续状态。本文以传统沥青路面设计理论中关于轮胎荷载的假设条件为基础,结合轮胎接地压力的影响因素及已有研究中的实测结果,对轮胎接地压力的分布情况进行数值简化。针对本文的研究手段,详细剖析了三维有限元数值仿真软件EverStressFE。以上两部分理论分析均是为后文的数值计算作铺垫。为描述轮载的非均匀性,运用三维有限元软件EverStressFE,建立了非均布垂直轮载作用下柔性基层沥青路面结构的有限元-无限元耦合数值模型,对比分析了不同轮载分布力作用下路表弯沉、路面结构剪应变、沥青层底弯拉应变、土基顶面竖向压应变的差异性,并讨论了非均布垂直轮载作用下影响柔性基层沥青路面结构寿命的控制指标。结果表明轮载非均匀作用对路表弯沉、路面结构剪应变的影响仅体现于局部区域,且对土基顶面竖向压应变的影响并不明显,行车方向的沥青面层底最大弯拉应变大于胎宽方向,路面结构预估寿命由永久变形控制。基于实际轮载的非均匀作用,为研究面层-基层、基层-底基层两界面层间结合状况对柔性基层沥青路面结构的影响,采用三维有限元软件EverStressFE,计算分析了完全连续和完全连续两种极端层间结合状况下的力学响应,并对路面结构寿命在不同层间结合状况下的动态演变规律进行了深入探究。结果显示：层间结合状况对路表弯沉、路面结构剪应变及弯拉应变、土基顶面压应变均有不同程度的影响；而路面结构疲劳寿命及永久变形寿命在层间结合状况逐渐恶化的过程中呈非线性态势衰减,在该过程中,路面结构损伤模式在永久变形及疲劳开裂间变换,增大了设计、施工、养护的难度；层间结合状况对柔性基层沥青路面结构的影响较轮载的非均匀作用更显著,且二者相对独立。
[Abstract]:With the development of flexible base asphalt pavement in developed countries, combined with its own national conditions and environment. At present, most of the design codes of asphalt pavement at home and abroad use circular uniform load to simulate the force of vehicles on the pavement structure. However, the distribution law of tire grounding pressure is extremely complex, and the contact surface shape is not circular, but close to ellipse and rectangle. Its force is more obvious non-uniformity, and the asphalt pavement layer material properties, construction procedures, construction quality control there are certain differences, resulting in a relatively weak interlayer bond. This paper is based on the assumption of tire load in the traditional asphalt pavement design theory, combined with the influence factors of tire grounding pressure and the measured results. The distribution of tire earthing pressure is simplified numerically. The three dimensional finite element numerical simulation software EverStressFE is analyzed in detail. The above two parts of the theoretical analysis are used to lay the groundwork for the later numerical calculation and to describe the inhomogeneity of the wheel load. Using the 3D finite element software EverStressFEE, the finite element and infinite element coupling numerical model of asphalt pavement structure with flexible base under the action of non-uniform vertical wheel loading is established. The differences of road surface deflection, pavement structure shear strain, asphalt bottom bending strain and vertical compressive strain under different wheel load distribution force are compared and analyzed. The control index of the structure life of flexible base asphalt pavement under the action of non-uniform vertical wheel load is discussed. The results show that the non-uniform effect of the wheel load on the road surface deflection, the influence of pavement structure shear strain is only in the local area. And the effect on the vertical compressive strain of the top surface of the soil foundation is not obvious. The maximum bending tension strain of the asphalt surface in the driving direction is larger than the direction of the tire width. The prediction life of pavement structure is controlled by permanent deformation. Based on the non-uniform effect of actual wheel load, the influence of the interface between the surface layer and the base course and the interface layer between the base and the bottom base on the asphalt pavement structure of the flexible base is studied. Three dimensional finite element software EverStressFEE is used to calculate and analyze the mechanical responses of two extreme interlaminar bonding conditions: completely continuous and completely continuous. The dynamic evolution law of pavement structure life under the condition of different interlaminar bonding is studied. The results show that the interlayer bonding condition is suitable for pavement surface deflection, pavement structure shear strain and flexural tension strain. The compressive strain of the top surface of the soil foundation is affected to some extent. However, the fatigue life and permanent deformation life of pavement structure attenuate in the process of the gradual deterioration of the interlayer bonding condition. In this process, the damage mode of pavement structure changes between permanent deformation and fatigue cracking. Increasing the difficulty of design, construction and maintenance; The effect of interlayer bonding on asphalt pavement structure of flexible base is more significant than that of non-uniform wheel load, and the two are relatively independent.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U416.217

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