【作者】 李华伟；

【导师】 王梦恕； 白冰；

【作者基本信息】 北京交通大学 ， 岩土工程， 2015， 博士

【摘要】 各类污染物(包括可溶性污染物和悬浮颗粒)迁移过程的研究已成为环境岩土工程研究的热点课题之一,这些研究在海洋隧道工程、污染物治理、化学工业、石油开采、核废料处置、注浆工程和土壤修复等领域有重要的学术意义和应用价值。本论文以氧化铝生产过程中产生的包含强碱性极细颗粒固体废物的废弃滤液的渗流迁移为研究背景,研究赤泥滤液的穿透特性和对岩土介质的污染和腐蚀性。为此,论文首先对国内外赤泥滤液的化学成分进行分析,然后就一种典型赤泥的穿透特性进行室内试验,分析其穿透规律和影响因素。在此基础上,对该类问题的穿透迁移过程进行理论分析和解析求解。论文主要的研究内容包括：(1)选用两种典型赤泥滤液样品,一种呈灰色,取自信发山西交口赤泥储库；一种为红褐色,取自信发山东赤泥储库。分析两种赤泥溶液的阳离子、碱性离子(如OH-根离子等)和酸性离子(如SO42-、NO3-等)的浓度,为赤泥穿透过程和抗腐蚀性研究提供依据。(2)对赤泥滤液在3种不同浓度和3种不同的渗流速度下进行室内石英砂土柱的穿透试验,研究物理因素对饱和多孔介质中具有强碱性赤泥滤液中悬浮颗粒和OH-1离子等的迁移特性的影响,并与中性滤液中颗粒的渗流穿透过程进行了比较,研究化学因素对饱和多孔介质中赤泥滤液中悬浮颗粒迁移特性的影响。比较了含OH-1离子和不包括OH-1离子两种情形下,浓度与浊度的率定关系曲线特征和差异,以探讨OH-1离子对赤泥颗粒穿透过程的影响。(3)对颗粒粒径为10μm和47μm两种粒径大小的天然硅粉组成的混合悬浮颗粒(质量各占50%),进行了3种浓度和3种渗流速度下的石英砂土柱穿透试验(不包括OH-1离子)。同时,比较了含OH-1离子和不包括OH-1离子两种情形下,天然硅粉悬浮颗粒浓度与浊度的率定关系曲线,以探讨OH-1离子对混合型硅粉率定曲线的影响,进而研究OH-1离子存在对天然硅粉颗粒迁移过程的影响。同时,进一步探讨OH-1离子对赤泥颗粒迁移过程影响的物理本质。(4)考虑了饱和多孔介质中悬浮颗粒沉积动力过程中的弥散效应,建立一个含有源项的悬浮颗粒一维渗透迁移模型,并通过Laplace变换及其逆变换求得面源问题的基本解。然后,利用源函数法推演一维多孔介质局部区域内具有悬浮颗粒释放源情形下的解答。考虑了释放源按指数形式衰减、释放源浓度按循环规律变化、污染物短期释放效应等情况下污染物迁移过程及其变化规律。(5)建立了考虑释放效应的一维渗透及三维弥散效应的渗透迁移模型,通过Laplace变换和Fourier变换及其逆变换求得相应控制方程的通解。然后利用“源函数法”的基本思想,通过积分方法得到半无限体表面局部区域上注入可溶性污染物时迁移过程的求解方法,并通过一个算例来加以验证。分析了圆形域上定浓度污染源迁移过程、污染物浓度按指数衰减规律迁移过程,以及污染源浓度呈循环变化过程变化等的演化过程。更多还原

【Abstract】 The migration processes of pollutants such as soluble contaminants and suspended particles have become an important research topic in environmental and geotechnical engineering. These researches have an important academic significance and application value in the field of ocean tunnelling engineering, pollutant treatment, chemical industry, oil exploration, nuclear waste disposal, grouting engineering in civil engineering and soil remediation, which is also the research task of this thesis. This thesis is to study the penetration properties of red mud and its pollution and corrosion in porous medium as the geotechnical engineering background. The chemical compositions of several typical red mud filtration are studied by laboratory tests, and the penetration characteristics and the problems of migration process in porous medium is analyzed. Then the migration process of contaminant in porous medium is analyzed by analytical method. The main research conclusions include:(1) The chemical compositions of two kinds of red mud filtrate samples, a gray sample from the Jiaokou of Shanxi project and a reddish brown sample from Shandong project, are analyzed, including the alkaline ion such as OH" and acidic ion such as SO42-and NO3-in the concentrations. These discussions provide the basis for the research of migration process of contaminant and corrosion resistance,(2) According to soil column penetration experiment of red mud,3different concentrations and3different flow velocities are discussed, and the effects of physical factors on the migration characteristics of red mud in saturated porous medium are studied, which include the transports of suspended particles and OH-1ion. The seepage and neutral filtrate penetration process are also studied, which is compared with the filtrate penetration process of red mud particles with strong alkaline. The influences of chemical factors on the migration characteristics of suspended particles of red mud filtrate in saturated porous medium are also analyzed. The difference of standard curves between concentration and turbidity of the red mud for the two cases with and without OH-1ion are compared; and furthermore the effect of OH-1ion on migration processes are investigated.(3) According to soil column penetration experiment of natural silica powder,3different concentrations and3different flow velocities are studied. This natural silica powder is composed of two different particles of10μm and47μm (mass50%each). In order to analyze the effect of OH-1ion on the migration process of silica powder, the difference of standard curves between concentration and turbidity of the silica powder for the two cases with and without OH-1ion are compared. Moreover, the physical inherit of OH-1ion on migration processes of red mud are discussed.(4) A mathematical model is developed to describe the seepage transport of particles in porous medium, which takes into account the diffusion effect in the process of deposition kinetics. Then, the general solution with an item of the particle source is obtained by Laplace transform and inverse Laplace transform. Based on the elementary solution of an instantaneous plane source, the semi-analytical solution of the particle transport equation is derived in a semi-infinite saturated porous media containing a particle source whose concentration varies with time and space. In the calculation example, many cases are discussed including the release source with decreasing exponentially, cyclic variation, and short-term release effect, etc.(5) The governing equations of contaminant transport in saturated porous medium with the release effect of absorbed solutes were established to account for the one-dimensional flow and three-dimensional dispersive effect. The elementary solution for the case of point contaminant source instantaneously applied on the surface of porous medium was derived by using the Laplace transform and Fourier transform and their transform inversions. Then, analytical expression for contaminant concentration in porous medium subjected to a local contaminant source with arbitrary geometry and varied intensity with time and coordinates on its free surface are developed by integration method. The migration processes of some typical cases are discussed including the cases of circular domain source with constant concentration of pollution, the pollution source with exponential decay and the pollution source with cyclic fluctuation, etc.更多还原