發(fā)布時間：2018-02-03 01:05

  本文關鍵詞： 瀝青路面 層間裂隙 斷裂力學 應力強度因子 疲勞試驗 疲勞壽命　出處：《重慶交通大學》2014年碩士論文　論文類型：學位論文

【摘要】：傳統(tǒng)的路面設計中，通常假定瀝青路面各結構層之間完全連續(xù)接觸，然而，現(xiàn)投入使用的大量半剛性基層瀝青路面中，由于材料或者施工因素的影響，導致結構層間不連續(xù)狀態(tài)的產生，形成了層間界面裂隙。界面裂隙的存在，改變了路面結構在豎直方向上的連續(xù)狀態(tài)，，并削弱結構的強度以及疲勞特性。本文以斷裂力學理論為基礎，采用試驗研究與數(shù)值模擬相結合的方法，研究界面裂隙對路面結構疲勞壽命的影響。 論文對基層與面層材料進行斷裂韌性測試。通過三點彎曲斷裂試驗可知，斷裂韌度KIC不會因為測量方法和試件尺寸的改變而改變，同時驗證了柔度標定法測量應力強度因子的可行性。 論文通過含有預制界面裂隙的水泥穩(wěn)定碎石-瀝青混凝土小梁的三點彎曲疲勞試驗，分析小梁的疲勞破壞特征，研究了三點彎曲小梁的疲勞壽命與疲勞斷裂路徑。試驗結果表明：界面裂隙在一定程度上降低了結構的強度與疲勞壽命，而且隨著裂隙長度的增加，這種效果越加明顯；應力比的越大，起裂出現(xiàn)的位置越靠近中間部位，裂縫的延伸方向越垂直上下表面，裂縫的曲折發(fā)展越少。 論文采用線彈性斷裂力學與有限元軟件ANSYS相結合的方法，分析在荷載作用下，界面裂隙尖端的應力強度因子變化規(guī)律，并計算不同初始長度裂隙的擴展壽命。結果表明：隨著裂隙的不斷擴展，張拉應力強度因子KI不斷增大，剪切應力強度因子KII不斷減小,等效應力強度因子呈線性關系增大，裂隙尖端呈現(xiàn)張開型和剪切型共同作用的復合型擴展模式;按照Paris公式計算得到在相同擴展長度下，裂隙的疲勞擴展壽命隨著初始長度的不斷增大而減小。 論文得到了交通土建工程材料國家地方聯(lián)合工程實驗室開放基金項目“瀝青路面結構層層間界面形態(tài)和細觀力學行為與路面疲勞損傷關系研究”的資助。
[Abstract]:In the traditional pavement design, it is usually assumed that there is a complete continuous contact between the structural layers of the asphalt pavement. However, a large number of semi-rigid base asphalt pavement in use now, due to the impact of materials or construction factors. It leads to the discontinuous state of the structure and the formation of interlayer interface crack. The existence of the interface crack changes the continuous state of the pavement structure in the vertical direction. Based on the theory of fracture mechanics, the influence of interface crack on fatigue life of pavement structure is studied by means of experimental study and numerical simulation. Through the three-point bending fracture test, the fracture toughness KIC will not change because of the change of measurement method and specimen size. At the same time, the feasibility of measuring the stress intensity factor by the flexibility calibration method is verified. Through the three-point bending fatigue test of cement stabilized macadam and asphalt concrete trabeculae with precast interface cracks, the fatigue failure characteristics of trabeculae are analyzed in this paper. The fatigue life and fatigue fracture path of three-point bending trabeculae are studied. The experimental results show that the interface fracture reduces the strength and fatigue life of the structure to some extent and increases with the length of fracture. This effect is more obvious; The greater the stress ratio, the closer the position of the initiation crack to the middle part, the more vertical the upper and lower surface of the crack, and the less the tortuous development of the crack. In this paper, the linear elastic fracture mechanics and the finite element software ANSYS are used to analyze the stress intensity factor variation law of the interface crack tip under load. The results show that the tensile stress intensity factor (Ki) increases and the shear stress intensity factor (KII) decreases as the crack expands. The equivalent stress intensity factor increases linearly, and the crack tip shows a compound expansion model of the joint action of open type and shear type. According to the Paris formula, it is found that the fatigue propagation life of fracture decreases with the increase of initial length under the same propagation length. In this paper, the open fund project of national local joint engineering laboratory of traffic civil engineering materials "study on the relationship between the interfacial morphology and meso-mechanical behavior of asphalt pavement structure and pavement fatigue damage" is obtained.
【學位授予單位】：重慶交通大學
【學位級別】：碩士
【學位授予年份】：2014
【分類號】：U416.21

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