【摘要】：滇池泥炭土作為軟粘土,其有機(jī)質(zhì)含量較大、孔隙比(e)和含水量(ω)較大,力學(xué)性質(zhì)較差。泥炭土上修建的建筑物容易產(chǎn)生不均勻沉降,因此對(duì)泥炭土物理力學(xué)性質(zhì)統(tǒng)計(jì)分析,微觀結(jié)構(gòu)特征的分析以及本構(gòu)模型的研究有很重要的理論價(jià)值和實(shí)用價(jià)值。本文通過(guò)收集昆明地鐵1、2線中滇池泥炭土的勘察數(shù)據(jù),并對(duì)其進(jìn)行統(tǒng)計(jì)分析。結(jié)合滇池泥炭土的電鏡掃描和組分分析實(shí)驗(yàn),對(duì)泥炭土微觀結(jié)構(gòu)進(jìn)行定性和定量的分析。通過(guò)單軸固結(jié)試驗(yàn)和常規(guī)三軸試驗(yàn)對(duì)泥炭土力學(xué)性質(zhì)進(jìn)行分析,并結(jié)合以上分析提出符合滇池泥炭土的改進(jìn)鄧肯-張模型。本文主要的研究成果如下：(1)收集昆明地鐵1、2號(hào)線滇池泥炭土原狀土樣的物理力學(xué)指標(biāo)數(shù)據(jù),對(duì)數(shù)據(jù)進(jìn)行統(tǒng)計(jì)和分析,列出滇池北部滇池泥炭土個(gè)物理力指標(biāo)的變化范圍,對(duì)該區(qū)域工程建設(shè)有一定的指導(dǎo)作用。其次對(duì)其個(gè)物理力學(xué)各指標(biāo)間的相互關(guān)系進(jìn)行研究,結(jié)果表明天然含水率與孔隙比、重度與孔隙比的相關(guān)較好,通過(guò)經(jīng)驗(yàn)公式可以獲得滇池泥炭土的孔隙比；有機(jī)質(zhì)含量與物理力學(xué)中各參數(shù)指標(biāo)關(guān)系度較��；通過(guò)統(tǒng)計(jì)的直剪試驗(yàn)和固結(jié)快剪試驗(yàn)的參數(shù)指標(biāo),發(fā)現(xiàn)其指標(biāo)之間的數(shù)據(jù)較離散,相關(guān)性較小。(2)通過(guò)能譜分析和微觀電子掃描電鏡試驗(yàn),表明滇池泥炭土的粘土礦物主要為伊利石、綠泥石,含有部分高嶺石；多組的SEM圖片的分析及前人研究將泥炭土的結(jié)構(gòu)特性主要分為三類：蜂窩狀結(jié)構(gòu),骨架裝結(jié)構(gòu),絮凝狀結(jié)構(gòu)；通過(guò)ImageJ軟件對(duì)SEM圖像處理,得出泥炭土的微觀結(jié)構(gòu)的定量參數(shù)。(3)通過(guò)單軸固結(jié)試驗(yàn)和常規(guī)三軸試驗(yàn),表明滇池泥炭土具有一定的結(jié)構(gòu)性,其原狀土跟重塑土的壓縮性有一定的區(qū)別,并對(duì)其進(jìn)行了微觀行為的解釋。滇池泥炭土的應(yīng)力應(yīng)變關(guān)系曲線可以分為三個(gè)階段：第一階段土體結(jié)構(gòu)較完整,其土體的變形中彈性變形為主要的；第二階段結(jié)構(gòu)破壞,其土體的塑性變形量比彈性變形量多；第三階段結(jié)構(gòu)完全破壞,此時(shí)段土的性質(zhì)跟重塑土相似。(4)介紹鄧肯-張模型的基本理論及所需參數(shù)的求解公式,同時(shí)引入了損傷比概念。使鄧肯-張模型具有三個(gè)不同的初始彈性模量,即土體完整階段的初始彈性模量,結(jié)構(gòu)破損階段的初始彈性模量,結(jié)構(gòu)完全破損階段的初始彈性模量。同時(shí)對(duì)模型進(jìn)行對(duì)比,表明修改后的模型較好的體現(xiàn)泥炭土的性質(zhì)。
[Abstract]:As soft clay in Dianchi Lake, the organic matter content, porosity ratio (e) and water content (蠅) of the peat soil in Dianchi Lake are large, and the mechanical properties are poor. The buildings built on the peat soil are prone to uneven settlement, so the statistical analysis of the physical and mechanical properties of the peat, the analysis of the microstructure characteristics and the study of the constitutive model are of great theoretical and practical value. In this paper, the survey data of the peat soil in Dianchi Lake in Kunming Metro Line 1 / 2 are collected and analyzed statistically. The microstructure of peat soil in Dianchi Lake was analyzed qualitatively and quantitatively by SEM and component analysis experiments. The mechanical properties of peat were analyzed by uniaxial consolidation test and conventional triaxial test, and an improved Duncan-Zhang model was put forward in accordance with the above analysis. The main research results of this paper are as follows: (1) collecting the physical and mechanical index data of the peat soil samples of Dianchi Lake in Kunming Metro Line 1 and 2, making statistics and analysis of the data, and listing the variation range of the physical force index of the peat soil in the northern Dianchi Lake. It has certain guiding function to the project construction in this area. Secondly, the relationship between physical and mechanical indexes is studied. The results show that the correlation between natural water content and porosity ratio, heavy degree and porosity ratio is better, and the porosity ratio of peat soil in Dianchi Lake can be obtained by empirical formula. The relationship between the content of organic matter and the parameters of physical mechanics is relatively small, and through the statistical direct shear test and consolidation fast shear test, it is found that the data between the two indexes are more discrete. (2) the clay minerals of the peat soil in Dianchi Lake are mainly Illite, chlorite and some kaolinite by energy dispersive analysis and SEM test. The structural characteristics of peat are divided into three types: honeycomb structure, skeleton structure, flocculation structure, SEM image processing by ImageJ software. The quantitative parameters of the microstructure of peat soil are obtained. (3) through uniaxial consolidation test and conventional triaxial test, it is shown that the peat soil in Dianchi Lake has a certain structure, and the compressibility of the undisturbed soil is different from that of the remolded soil. The microcosmic behavior is explained. The stress-strain relationship curve of peat soil in Dianchi Lake can be divided into three stages: in the first stage, the soil structure is relatively complete, the elastic deformation is the main part of the soil deformation, the second stage is the structure failure, the plastic deformation of the soil is more than that of the elastic deformation. In the third stage, the properties of the soil are similar to those of the remolded soil. (4) the basic theory of Duncan-Zhang model and the formula of the required parameters are introduced, and the concept of damage ratio is introduced. The Duncan-Chang model has three different initial elastic moduli, that is, the initial elastic modulus in the complete stage of soil, the initial elastic modulus in the stage of structural damage, and the initial elastic modulus in the stage of complete damage of the structure. At the same time, the comparison of the model shows that the modified model well reflects the properties of peat.
【學(xué)位授予單位】：昆明理工大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：TU447;TU411

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