發(fā)布時間：2018-06-22 04:20

  本文選題：級配碎石 + 有限元法��； 參考：《重慶交通大學》2015年碩士論文

【摘要】：與傳統(tǒng)半剛性基層瀝青路面相比,級配碎石基層瀝青路面具有排水性好、行車舒適度提高的特點,可減小基層與面層的模量差,降低反射裂縫的出現(xiàn)幾率。然而,級配碎石屬于無粘結(jié)性材料,其力學強度主要依靠骨料之間的嵌擠,需要形成骨架密實型結(jié)構(gòu),并且在有側(cè)限條件下才能發(fā)揮較好的受力作用。本文通過試驗及理論模擬研究,優(yōu)選級配碎石基層的級配類型和層間粘結(jié)類型,力求彌補級配碎石力學強度的不足,充分發(fā)揮其排水性能良好等優(yōu)點,使之在公路建設(shè)中得到更廣泛的應用。通過靜態(tài)CBR試驗和回彈模量試驗,發(fā)現(xiàn)級配碎石具有最大干密度越大,對應的CBR值越大,變形率相應越小,回彈模量越大的特點。在此基礎(chǔ)上,運用Cooper氣動伺服試驗機進行動態(tài)CBR試驗,測試應變變化的相關(guān)系數(shù)以及蠕變模量值,變化率越小,蠕變模量值增加,力學性能越優(yōu)。運用ABAQUS有限元軟件構(gòu)建模型,從上到下依次分為瀝青混合料面層、稀漿封層、透層油(乳化瀝青)、級配碎石、土基。為體現(xiàn)級配碎石的顆粒性及非均勻性特點,采用D-P模型對其進行定義;定義面層和稀漿封層為彈性材料。優(yōu)選三種基層級配,分別設(shè)置不同封層厚度條件,施加標準荷載和邊界條件,計算有限元模型,對豎向位移、軸向應力和剪切應力進行對比分析。經(jīng)過試驗研究和理論分析,改善級配碎石基層的力學性能有助于提高柔性基層瀝青混合料路面的強度和抗變形能力;使用粗顆粒較多的稀漿封層級配類型ES-3,并適當增加封層厚度,有益于路面結(jié)構(gòu)層間粘結(jié)強度提高;級配類型、封層厚度兩個因素,級配類型影響較明顯。溫度是柔性基層瀝青路面不可忽視的影響因素,經(jīng)過豎向位移和Mises應力綜合分析,得出在荷載作用下,溫度在0~10℃范圍內(nèi)對路面結(jié)構(gòu)的影響最小。本文采用自制模具成型疲勞試驗試件,以45°斜剪試驗作為疲勞試驗方法,結(jié)果表明疲勞行為與級配碎石基層類型及層間粘結(jié)情況有關(guān),依據(jù)試驗測出的疲勞作用次數(shù),結(jié)合基層級配碎石回彈模量、封層厚度、沿著行車方向?qū)娱g應力進行疲勞壽命預估方程的擬合,得出建議性的疲勞壽命預估模型;同時,擬合結(jié)果具有保守性和延展性,具有一定的實際應用價值。
[Abstract]:Compared with the traditional semi-rigid base asphalt pavement, graded crushed stone base asphalt pavement has the characteristics of better drainage and better driving comfort, which can reduce the modulus difference between the base and surface layer and reduce the probability of reflection cracks. However, graded macadam is an unbonded material, its mechanical strength mainly depends on the intercalation between aggregates, and it needs to form a dense skeleton structure, and it can play a better force under the condition of side limit. In this paper, through experimental and theoretical simulation, the gradation type and interlaminar bond type of graded crushed stone base are selected to make up for the shortage of mechanical strength of graded crushed stone and to give full play to its good drainage performance. So that it is more widely used in highway construction. Through static CBR test and elastic modulus test, it is found that the higher the maximum dry density, the larger the CBR value, the smaller the deformation rate and the greater the resilience modulus of graded crushed stone. On this basis, the dynamic CBR test is carried out with Cooper pneumatic servo testing machine. The correlation coefficient of strain variation and creep modulus are measured. The smaller the change rate is, the higher the creep modulus value is, and the better the mechanical properties are. Abaqus finite element software is used to construct the model, which is divided into asphalt mixture surface layer, slurry seal layer, permeable oil (emulsified asphalt), graded crushed stone and soil foundation. In order to reflect the particularity and non-uniformity of graded macadam, D-P model was used to define it, and the surface layer and slurry seal layer were defined as elastic materials. Three kinds of base-bed gradation were selected, different sealing layer thickness conditions were set up, standard load and boundary conditions were applied, finite element model was calculated, and vertical displacement, axial stress and shear stress were compared and analyzed. Through experimental research and theoretical analysis, improving the mechanical properties of graded crushed stone base is helpful to improve the strength and deformation resistance of asphalt mixture pavement with flexible base. It is beneficial to increase the interlayer bond strength of pavement structure by using the slurry sealing hierarchy type ES-3 with more coarse particles and increase the thickness of sealing layer properly. The gradation type and sealing layer thickness are two factors which have obvious influence on the interlayer bond strength of pavement structure. Temperature is an important influence factor of asphalt pavement with flexible base. Through the comprehensive analysis of vertical displacement and Mises stress, it is concluded that the influence of temperature on pavement structure is the least in the range of 0 ~ 10 鈩，

本文編號：2051562