云南高海拔地區(qū)瀝青混合料性能仿真研究

1、云南高海拔地區(qū)瀝青混合料性能仿真研究云南高海拔地區(qū)瀝青混合料性能仿真研究 High-altitude Areas in Yunnan Asphalt Mixture Performance Simulation【中文摘要】 云南高海拔地區(qū),在氣候特征上屬于濕潤溫帶-寒溫帶氣候,而青藏高原多屬于半干旱和干旱-高原寒帶季風(fēng)性氣候,其降雨量遠(yuǎn)遠(yuǎn)高于青藏高原。由于氣候條件的不同,使得其筑路條件也就不同,在青藏高原筑路面臨的主要問題是多年凍土問題,而云南高海拔地區(qū)則沒有多年凍土問題,筑路面臨的主要是季節(jié)性凍融問題。就凍融問題而言,云南高海拔地區(qū)的凍融問題遠(yuǎn)比我國北方地區(qū)凍融問題嚴(yán)重,主要表現(xiàn)在其凍融期較

2、長(最長達(dá)300天),且凍融變化頻繁。因此,在云南高海拔地區(qū)筑路,即不能套用青藏高原地區(qū)相關(guān)筑路經(jīng)驗(yàn),也不能套用北方地區(qū)解決凍融問題的經(jīng)驗(yàn),而必須根據(jù)云南高海拔地區(qū)的具體特點(diǎn),有針對性的研究開發(fā)其筑路技術(shù)。隨著云南高海拔地區(qū)公路建設(shè)的發(fā)展,近年來由于當(dāng)?shù)丶竟?jié)性凍融原因即其特殊的氣候環(huán)境,使得路面修筑過程中出現(xiàn)的工程問題及使用期的早期破壞現(xiàn)象越發(fā)明顯。當(dāng)前的瀝青混合料級配組成設(shè)計(jì)基本上仍是沿用傳統(tǒng)的實(shí)驗(yàn)-觀察的現(xiàn)象學(xué)經(jīng)驗(yàn)方法,應(yīng)用先進(jìn)的計(jì)算手段、力學(xué)分析工具,定量地分析微觀或細(xì)觀尺度瀝青混合料的力學(xué)特征,對深刻理解瀝青混合料的力學(xué)機(jī)理與改進(jìn)瀝青混合料組成設(shè)計(jì)方法有重要意義。當(dāng)前研究工作在數(shù)字圖像

3、獲取與處理技術(shù)、虛擬力學(xué)計(jì)算軟件、分形原理等方面得到了迅速發(fā)展,這些技術(shù)的發(fā)展已被認(rèn)為是道路工程界非常有潛力的一些研究發(fā)展方向。由于特殊的地理及氣候條件,云南高海拔地區(qū)瀝青路面病害較其他更為復(fù)雜,為了研究云南高海拔地區(qū)特殊氣候條件下瀝青混合料的力學(xué)性能,本文在借鑒國內(nèi)外相關(guān)研究成果的基礎(chǔ)上,結(jié)合云南高海拔地區(qū)特殊的氣候條件,建立適用于模擬瀝青混合料真實(shí)相互作用的離散單元模型進(jìn)行計(jì)算機(jī)虛擬試驗(yàn),通過實(shí)驗(yàn)結(jié)果和數(shù)值模擬結(jié)果對比分析,建立宏觀與細(xì)觀參數(shù)之間的關(guān)系。在室內(nèi)試驗(yàn)結(jié)果分析總結(jié)的基礎(chǔ)上,在獲得科學(xué)數(shù)據(jù)的基礎(chǔ)上進(jìn)行理論分析和評價(jià),探討PFC2D模擬瀝青混合料大粒徑的可行性分析。 【英文摘要】

4、Yunnan,high-altitude areas, belong to the climatic characteristics on humid temperate - cold temperate climate, and the Qinghai-Tibet Plateau belong to semi-arid and dry - cold plateau monsoon climate, its rainfall is much higher than the inghai-Tibet Plateau. Because of different climatic condition

5、s, making it different from the onditions of its roads, and roads in the Qinghai-Tibet Plateau are the main problems facing the permafrost problem, and high-altitude areas in Yunnan there is no permafrost problems, the main roads are seasonal freeze-thaw problem. Question on freezing and thawing, th

6、e Yunnan high altitude than the problem of freeze-thaw Freeze-thaw in northern China the problem is serious, mainly reflected in its freeze-thaw for long periods of time (up to 300 days), and the frequent freezing and thawing Change. Therefore, high-altitude areas in Yunnan, and roads, that is, shou

7、ld not apply the relevant construction experience in the Qinghai-Tibet Plateau region, and should not be applied to solve the northern region experience freeze-thaw problem. And must be based on high-altitude areas in Yunnan specific characteristics, targeted research and development of its road con

8、struction technology.With the high-altitude areas of Yunnan highway construction development, in recent years because of local reasons for the seasonal freezing and thawing that is, its special climate and environment, making road construction projects arising in the course of questions and use the

9、early phase of situation all the more obvious damage. The current asphalt mixture gradation component design is still a traditional experiment - observe the phenomenon of the experience of study methods, the application of advanced computing tools, mechanical analysis tools, quantitative analysis of

10、 micro-or meso-scale asphalt mixture mechanical characteristics on a deep understanding of asphalt mixture mechanical mechanism and improve the composition of asphalt mixture design method has important significance. Current research work in the digital image acquisition and processing technology, v

11、irtual mechanics calculation software, and so on fractal principle has been the rapid development of these technologies has been the development of road engineering are very think there is some potential for research and development direction.Because of special geographical and climatic conditions,

12、high-altitude areas in Yunnan Asphalt Pavement more complex than the other, in order to study high-altitude areas in Yunnan special climatic conditions of asphalt mixture mechanical properties, in this paper draw on relevant research results at home and abroad on the basis of combination of high-alt

13、itude areas in Yunnan special climatic conditions, set up for asphalt mixture Analog real discrete element model of the interaction of the virtual computer experiments, through the experimental results and numerical simulation results of comparative analysis, the establishment of macro-and micro-par

14、ameters of the relationship between. Analysis of laboratory test results at the basis of summing up, in access to scientific data based on theoretical analysis and evaluation 【中文關(guān)鍵詞】 高海拔地區(qū); 離散元; 三軸試驗(yàn); 剪應(yīng)力 【英文關(guān)鍵詞】 high-altitude areas; discrete element; triaxial test; shear stress 【畢業(yè)論文目錄】摘要 3-4 ABSTR

15、ACT 4-5 第一章 前言 9-20 1.1 引言 9-11 1.2 研究的背景和意義 11 1.3 瀝青混合料微觀結(jié)構(gòu)的國內(nèi)外研究現(xiàn)狀 11-14 1.3.1 瀝青混合料的細(xì)觀結(jié)構(gòu)識(shí)別 11-13 1.3.2 瀝青混合料的微觀結(jié)構(gòu)特性的數(shù)值模擬 13-14 1.4 離散單元法在國內(nèi)外研究概況及在瀝青混合料結(jié)構(gòu)分析中的應(yīng)用 14-18 1.4.1 離散單元法在國外的發(fā)展?fàn)顟B(tài) 15-16 1.4.2 離散單元法在國內(nèi)的發(fā)展?fàn)顟B(tài) 16-18 1.4.3 離散單元法在瀝青混合料微觀結(jié)構(gòu)分析中的應(yīng)用 18 1.5 本文的主要研究內(nèi)及技術(shù)路線 18-19 1.6 工程背景及研究意義 19-20 第二章

16、 離散單元法的基本原理及PFC2D 程序簡介 20-39 2.1 離散單元法基本思想 20 2.2 離散單元法的數(shù)值求解 20-21 2.3 PFC2D 簡介 21-24 2.3.1 PFC2D 的發(fā)展概況 21-22 2.3.2 PFC2D 方法的特點(diǎn) 22-23 2.3.3 PFC2D 基本理論 23 2.3.4 PFC2D 模擬步驟 23-24 2.4 顆粒離散單元法模型假設(shè)及思路 24-26 2.5 計(jì)算循環(huán) 26-34 2.5.1 力-位移關(guān)系法則 27-31 2.5.2 運(yùn)動(dòng)定律 31-33 2.5.3 計(jì)算方法動(dòng)態(tài)松弛法 33-34 2.6 邊界條件和初始條件 34 2.6.1

17、以墻為邊界條件 34 2.6.2 以顆粒單元為邊界條件 34 2.6.3 初始條件 34 2.7 相對滑動(dòng)模型 34-35 2.8 計(jì)算參數(shù)的確定 35-38 2.8.1 時(shí)步的確定 35-36 2.8.2 機(jī)械阻尼的確定 36-37 2.8.3 剛度及摩擦系數(shù)的選取 37-38 2.8.4 微分密度因子 38 2.9 本章小結(jié) 38-39 第三章 云南高海拔地區(qū)瀝青混合料仿真分析模型 39-57 3.1 引言 39-41 3.2 瀝青混合料的強(qiáng)度機(jī)理 41-45 3.3 瀝青混合料細(xì)觀結(jié)構(gòu)模型的基本假設(shè) 45 3.4 瀝青混合料數(shù)值結(jié)構(gòu)力學(xué)模型 45-56 3.4.1 結(jié)構(gòu)離散化產(chǎn)生離散單元 45-46 3.4.2 離散單元接觸模型 46-53 3.4.3 構(gòu)造離散元計(jì)算模型 53-54 3.4.4 構(gòu)造離散元計(jì)算模型 54-56 3.5 瀝青混合料細(xì)觀結(jié)構(gòu)模型特點(diǎn) 56-57 第四章 云南高海拔地區(qū) pfc2d 數(shù)值模擬及結(jié)果分析 57-88 4.1 數(shù)值分析涉及的參數(shù) 57-69 4.1.1 關(guān)鍵參數(shù)選取及相應(yīng)的PFC2D 命令 57-58 4.1.2 PFC2D 中一些參數(shù)及相應(yīng)的確定方法 58-68 4.1.3 伺服控制機(jī)制 68-69 4.2 云南高海拔地區(qū)瀝青混合料三軸剪切試驗(yàn)?zāi)M及分析 69-87 4.2.1