非均布垂直輪載作用下柔性基層瀝青路面結構力學行為研究
發(fā)布時間:2018-01-15 03:22
本文關鍵詞:非均布垂直輪載作用下柔性基層瀝青路面結構力學行為研究 出處:《西南交通大學》2015年碩士論文 論文類型:學位論文
更多相關文章: 柔性基層瀝青路面 輪載的非均勻性 層間結合 路面結構壽命 有限元法
【摘要】:隨著發(fā)達國家柔性基層瀝青路面的發(fā)展,結合自身國情與環(huán)境,我國相關機構逐漸將該類路面結構形式應用于高等級公路中。目前國內外瀝青路面設計規(guī)范大多采用圓形均布荷載模擬車輛對路面結構的作用力,且假定各結構層間完全連續(xù)。然而,輪胎接地壓力分布規(guī)律極其復雜,其接觸面形狀也并非圓形,而是接近于橢圓形、矩形,其作用力更是表現出明顯的非均勻性,且瀝青路面各結構層材料性質、施工工序、施工質量控制存在一定差異,導致層間粘結較為薄弱,無法達到理想的完全連續(xù)狀態(tài)。本文以傳統(tǒng)瀝青路面設計理論中關于輪胎荷載的假設條件為基礎,結合輪胎接地壓力的影響因素及已有研究中的實測結果,對輪胎接地壓力的分布情況進行數值簡化。針對本文的研究手段,詳細剖析了三維有限元數值仿真軟件EverStressFE。以上兩部分理論分析均是為后文的數值計算作鋪墊。為描述輪載的非均勻性,運用三維有限元軟件EverStressFE,建立了非均布垂直輪載作用下柔性基層瀝青路面結構的有限元-無限元耦合數值模型,對比分析了不同輪載分布力作用下路表彎沉、路面結構剪應變、瀝青層底彎拉應變、土基頂面豎向壓應變的差異性,并討論了非均布垂直輪載作用下影響柔性基層瀝青路面結構壽命的控制指標。結果表明輪載非均勻作用對路表彎沉、路面結構剪應變的影響僅體現于局部區(qū)域,且對土基頂面豎向壓應變的影響并不明顯,行車方向的瀝青面層底最大彎拉應變大于胎寬方向,路面結構預估壽命由永久變形控制;趯嶋H輪載的非均勻作用,為研究面層-基層、基層-底基層兩界面層間結合狀況對柔性基層瀝青路面結構的影響,采用三維有限元軟件EverStressFE,計算分析了完全連續(xù)和完全連續(xù)兩種極端層間結合狀況下的力學響應,并對路面結構壽命在不同層間結合狀況下的動態(tài)演變規(guī)律進行了深入探究。結果顯示:層間結合狀況對路表彎沉、路面結構剪應變及彎拉應變、土基頂面壓應變均有不同程度的影響;而路面結構疲勞壽命及永久變形壽命在層間結合狀況逐漸惡化的過程中呈非線性態(tài)勢衰減,在該過程中,路面結構損傷模式在永久變形及疲勞開裂間變換,增大了設計、施工、養(yǎng)護的難度;層間結合狀況對柔性基層瀝青路面結構的影響較輪載的非均勻作用更顯著,且二者相對獨立。
[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.
【學位授予單位】:西南交通大學
【學位級別】:碩士
【學位授予年份】:2015
【分類號】:U416.217
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