【摘要】：在我國經(jīng)濟繁榮發(fā)展和西部大開發(fā)戰(zhàn)略持續(xù)深入的前提背景下,近年來在云貴川等我國西部地區(qū)投入了大批資源進行基礎設施建設,其中航空運輸業(yè)發(fā)展優(yōu)勢尤其明顯,在各地一大批支線機場相繼展開建設,部分機場開始擴容改建。與中原地區(qū)和東部沿海地區(qū)相比,西部地區(qū)地質(zhì)條件更為復雜多變,由此在設計階段與實際建設都產(chǎn)生了許多特殊的工程問題,例如地基高填方處理、高海拔建設、高地震烈度、極端氣候條件施工、高邊坡、地質(zhì)條件復雜,工作質(zhì)量高要求等問題。在西南山區(qū)機場建設中經(jīng)�？梢姼咛罘竭吰�,其所采用填料多為就地取材的巖石爆破材料,這些填料具有巖性復雜、粒徑巨大等特點�，F(xiàn)有大量工程實際經(jīng)驗可知,高填方填筑體沉降變形控制和蠕變特性研究是山區(qū)高填方機場修建目前所存在的主要問題和難點。本文針對西部山區(qū)機場高填方工程建設中遇到的此類問題,將重慶萬州機場填方工地土樣作為研究對象,通過室內(nèi)基本力學實驗、理論分析、數(shù)值模擬等手段進行系統(tǒng)性研究,主要研究內(nèi)容和成果如下:(1)通過閱讀和研究大量的國內(nèi)外關于土體蠕變特性的文獻,總結(jié)了近年來蠕變模型和研究方法,并對各種研究方法做出了系統(tǒng)的介紹,給出了其適用范圍和存在的問題,發(fā)現(xiàn)在后續(xù)研究中可能遇到的困難。(2)基于室內(nèi)常規(guī)土工試驗,并結(jié)合現(xiàn)場實測資料,對碎石土填料的基本力學性質(zhì)、物理指標等進行了系統(tǒng)的歸納和總結(jié)。通過室內(nèi)單軸壓縮試驗確定土樣的壓縮強度,壓縮模量等指標,為后續(xù)的固結(jié)蠕變試驗與蠕變模型研究提供了依據(jù)。(3)以砂泥巖碎石土填料為研究對象,結(jié)合高填方工后沉降變形機理與工程特點,在大口徑固結(jié)儀上進行一維壓縮蠕變試驗研究,發(fā)現(xiàn)巨粒混合土具有明顯的衰減蠕變特征。應力水平越高,蠕變現(xiàn)象越顯著。選擇了合理的經(jīng)驗公式描述了應變-時間、應力-應變的關系。此外,擬合了壓實土的對數(shù)形式蠕變方程和含應力影響的冪函數(shù)蠕變模型,表征了壓實土的應力與應變關系,并從微觀角度解釋了壓實土的蠕變變形機理。(4)利用復合組件Burgers體模型對一維固結(jié)蠕變結(jié)果做了分析,并得到了模型的相關參數(shù),并對參數(shù)的意義和變化規(guī)律做了深入的分析。通過對比理論曲線與試驗曲線發(fā)現(xiàn),Burgers組件組合模型擬合效果較理想。(5)利用巖土工程分析軟件FLAC3D內(nèi)置的Burgers體模型對土樣蠕變試驗進行了數(shù)值模擬分析,通過與經(jīng)驗公式、理論模型對比驗證了模型的合理性,對以后高填方工程沉降計算有很大實用價值。
[Abstract]:Under the premise of the prosperous development of our country's economy and the development strategy of the western China, in recent years, a large number of resources have been invested in the construction of infrastructure in the west of China, such as Yungui Sichuan, especially in the air transport industry. A large number of local regional airports have started construction, some airports began to expand and rebuild. Compared with the Central Plains and the eastern coastal areas, the geological conditions in the western region are more complex and changeable. As a result, many special engineering problems have arisen in both the design stage and the actual construction, such as foundation high fill treatment and high altitude construction. Problems such as high seismic intensity, extreme climatic conditions, high slope, complex geological conditions, high working quality and so on. The high fill slope is often found in the airport construction in southwest mountainous area. The fillers are mostly rock blasting materials which are made locally. These fillers have the characteristics of complex lithology and huge particle size. A large number of practical engineering experiences show that the study of settlement deformation control and creep characteristics of high fill is the main problem and difficulty in the construction of high fill airport in mountainous area. In view of the problems encountered in the construction of high fill engineering of airport in western mountainous area, this paper takes the soil samples from the filling site of Chongqing Wanzhou Airport as the research object, and carries out systematic research by means of indoor basic mechanics experiment, theoretical analysis, numerical simulation and so on. The main research contents and results are as follows: (1) through reading and studying a large number of domestic and foreign literatures on soil creep characteristics, the creep models and research methods in recent years are summarized, and various research methods are systematically introduced. The scope of application and the existing problems are given, and the difficulties that may be encountered in the subsequent research are found. (2) based on the indoor routine geotechnical test and the field measured data, the basic mechanical properties of the gravel filler are studied. The physics index and so on have carried on the systematic induction and the summary. The compression strength and modulus of soil samples are determined by uniaxial compression test in laboratory, which provides a basis for the subsequent study of consolidation creep test and creep model. (3) taking sand and mudstone gravel fill as the research object, Combined with the mechanism of settlement and deformation after construction and engineering characteristics of high fill, one-dimensional compression creep test was carried out on a large caliber consolidation instrument. It was found that the large grained mixed soil had obvious attenuation creep characteristics. The higher the stress level, the more obvious the creep phenomenon. A reasonable empirical formula is chosen to describe the relationship between strain and time, stress and strain. In addition, the logarithmic form creep equation of compacted soil and the power function creep model with stress effect are fitted to characterize the stress-strain relationship of compacted soil. The creep deformation mechanism of compacted soil is explained from the microscopic point of view. (4) the one-dimensional consolidation creep results are analyzed by using the composite component Burgers body model, and the related parameters of the model are obtained, and the significance and variation law of the parameters are deeply analyzed. By comparing the theoretical curves with the experimental curves, it is found that the fitting effect of the combined model of Burgers component is satisfactory. (5) the creep tests of soil samples are numerically simulated and analyzed by using the Burgers model built in the geotechnical engineering analysis software FLAC3D. The comparison of theoretical models verifies the rationality of the model and has great practical value for the settlement calculation of high fill projects in the future.
【學位授予單位】：成都理工大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TU411

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