混合赤泥胶结硬化机理研究及其工程应用

发布时间：2018-03-07 20:39

本文选题：赤泥　切入点：胶结硬化　出处：《重庆大学》2015年博士论文　论文类型：学位论文

【摘要】：赤泥是铝土矿经各种物理化学处理,制取氧化铝后所剩余的一种黄色或褐色粉泥状、高含水量的强碱性固体废料。由于赤泥的强碱性,使其重复利用受到限制,露天筑坝堆存是我国现处理赤泥的主要措施。随着制铝工业的大发展,赤泥量不断增加,现有的赤泥库库容已经达到饱和,修建新的赤泥库又受到各种限制,就需要利用现有坝体继续向上堆存新产赤泥。这就需要我们研究新堆载赤泥在堆存过程中的物理化学特性、力学特性和水力学特性的变化规律,为利用现有赤泥堆场继续安全向上堆存提供一定的理论依据。论文在贵州省教育厅《赤泥堆载固结特性理论及试验研究》黔科教(2011)007号项目的支持下,选用中国铝业贵州分公司生产的烧结法赤泥和拜耳法赤泥按照配合比1:1混合的混合赤泥为试验试样,对混合赤泥进行了室内常规试验及微观分析试验,以确定混合赤泥在堆存过程中其物理力学特性、微观结构组成及水力学特性的变化规律,并以此为基础,提出了混合赤泥结构性定量化参数mc的计算公式,修正了邓肯-张模型,完成了在不同降雨工况下、不同堆存高度混合赤泥堆体的稳定性分析。论文针对贵州铝厂赤泥堆存特点,对以下内容进行了研究:(1)在充分了解贵州铝厂堆存历史和堆场水文地质条件的基础上,选取了符合试验目的、具有代表性的烧结法赤泥、拜耳法赤泥和两者按照配合比1:1混合的干法堆存的混合赤泥。并通过无侧限抗压强度试验和三轴剪切试验(CD)测定了干法混合赤泥在自然风干、浸水浸泡、非饱和-饱和干湿循环三种工况条件下随着堆存龄期的增长,其抗压强度和抗剪强度指标的变化规律。为了突出混合赤泥的工程特性的特殊性,同时研究了拜耳法赤泥和烧结法赤泥的强度特性。(2)通过X射线荧光光谱分析(XRF)、X射线衍射(XRD)、扫描电子显微镜(SEM)等微观测试手段分析了自然风干混合赤泥试样在5个龄期化学成分、矿物组成和微观结构的变化情况,揭示了混合赤泥胶结强度形成的微观机理。同时在分析了混合赤泥胶结强度形成的物理化学反应的基础上,通过对混合赤泥浸泡不同类型、不同浓度的酸溶液,研究了碳酸钙矿物质对混合赤泥胶结强度形成的作用机理。(3)利用非饱和土瞬态水力特性循环试验系统研究了烧结法赤泥、拜耳法赤泥和混合赤泥的水力学特性,得到了三者的土-水特征曲线(SWCC)和水力传导率特性曲线(HCFC),并从微观角度分析了三种赤泥不同滞后效应产生的微观机理,为研究赤泥堆体在降雨条件下的稳定性提供一定依据。(4)在通过三轴剪切试验得到混合赤泥不同工况、不同龄期应力-应变曲线的基础上,提出了非饱和混合赤泥的结构性参数mc,建立了适用于非饱和混合赤泥含结构性参数的邓肯-张修正模型,得到了邓肯-张模型基本参数Kc、nc、cc、φc与龄期t的拟合关系式,建立了切线弹性模量Ect与龄期t的关系表达式,并通过反算验证了结构性本构关系的正确性。(5)利用加拿大GEO-SLOPE公司开发的Geo Studio系列有限元软件SLOPE/W、SEEP/W和SIGMA/W三个模块对不同降雨条件下、不同堆存高度的混合赤泥堆体的稳定性进行了耦合分析,对赤泥堆体在三种不同降雨工况下,堆体高程分别为1380 m、1390 m时的安全系数进行了计算。
[Abstract]:The red mud is bauxite by various physical and chemical treatment, a yellow or brown powder mud remaining after the preparation of alumina, alkaline solid waste with high moisture content. Due to the strong alkaline red mud, the repeated use of limited open storage is the main dam measures in China now deal with red mud. With the great development of aluminum industry, the increasing amount of red mud, the red mud storage capacity has already reached saturation point, to build a new library of red mud is limited, you need to use the existing dam to the new production of red mud stockpiling. This requires us to study new physical and chemical properties of red mud pile load in the course of storing mechanical properties and changes. Hydraulic characteristics, to use the existing red mud yard is safe to continue to provide a theoretical basis to storage. The Education Department of Guizhou province "red mud load consolidation characteristics of the theoretical and Experimental Research on Guizhou science and Education (2011) > 0 No. 07 project supported by the China sintering red mud aluminum Guizhou branch production and in accordance with the proportion of Bayer red mud mixed red mud mixed 1:1 as test samples of mixed red mud were normal indoor tests and microscopic test, to determine the mixed red mud in the course of storing the physical and mechanical properties, microstructure changes the composition and hydraulic characteristics, and on this basis, puts forward the calculation formula of mixed red mud structural quantitative parameters of MC, modified Duncan Chang model, completed in different rainfall conditions, stability analysis of different storage height mixed red mud pile. According to the Guizhou red mud storage characteristics, studies the following contents: (1) based on the full understanding of history and Guizhou aluminum storage yard on the hydrogeological conditions, selected in line with the test purpose, sintering of red mud by the representative, thanks Method of red mud and two according to the proportion of mixed dry red mud piling 1:1 mixture. And the unconfined compressive strength test and the three axle shear test (CD) in dry mixed red mud dry naturally, the determination of water soaked and saturated unsaturated cyclic wetting and drying under the three working conditions with the stockpiling of age, the compressive strength and shear strength index changes. In order to highlight the special engineering properties of red mud mixing, and strength properties of Bayer red mud and red mud in sintering process was studied. (2) by X ray fluorescence spectrometry (XRF), X ray diffraction (XRD), scanning electron microscopy (SEM) etc. microscopic test method of natural air dry mixed red mud samples in 5 age changes in chemical composition, mineral composition and microstructure, microscopic mechanism of formation of mixed red mud cementation strength was revealed. At the same time in the analysis of mixed red mud cementation strength Based on the formation of physical and chemical reactions, the mixed red mud soaked in different types, different concentration of acid solution, the mechanism of calcium carbonate minerals on bonding strength of red mud mixed formation was studied. (3) the unsaturated soil hydraulic characteristics of transient cycle test system of sintering red mud utilization, hydraulic characteristics of Bayer red mud and mixed red mud, got three of the soil water characteristic curve (SWCC) and hydraulic conductivity curve (HCFC), and analyze the microcosmic mechanism of three kinds of red mud of different lag effect, provides the basis for the stability of pile body under rainfall condition of red mud (4) in the mixed. The red mud in different conditions obtained by the three axle shear test, different age of stress - strain curve, puts forward the structural parameters of MC unsaturated mixed red mud, built for unsaturated mixed red mud containing structural The parameters of Duncan Chang model, the basic parameters of Duncan Chang model Kc, NC, CC, C and the relation between the age of T, the relationship between the expression of tangent elastic modulus Ect and the age of T is established, and through calculation to verify the correctness of the structural constitutive relation (5). The Canada SLOPE/W Geo Studio series of finite element software development company GEO-SLOPE, SEEP/W and SIGMA/W three modules for different rainfall conditions, the height of the storage stability of different mixed red mud pile of body coupling analysis in three different rainfall conditions of red mud pile, the pile height was 1380 m, security the coefficient of 1390 m was calculated.

【学位授予单位】：重庆大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：TV649;TV223

【参考文献】