本文選題：脫硫石膏　切入點：粉煤灰　出處：《內(nèi)蒙古農(nóng)業(yè)大學》2015年博士論文　論文類型：學位論文

【摘要】：水泥土耐久性和固化機理研究是在北方寒區(qū)推廣和應(yīng)用水泥土的關(guān)鍵。鑒于普通水泥土強度低,耐久性差的特點,同時為解決我區(qū)燃煤電廠產(chǎn)生的大量工業(yè)廢料粉煤灰和脫硫石膏,特提出利用它們配制出一種新型的復(fù)合水泥土材料。然后開展室內(nèi)試驗,研究這種復(fù)合材料的力學特性、耐久性、損傷特性及固化機理,為將該復(fù)合材料在內(nèi)蒙古地區(qū)的廣泛應(yīng)用提供理論依據(jù)和試驗數(shù)據(jù)。1、建立了復(fù)合水泥土的強度預(yù)測模型,提出了各組分材料的最優(yōu)配合比。(1)通過開展不同水泥摻入比、不同齡期及不同試件規(guī)格及成型方法下普通水泥土的無側(cè)限抗壓強度試驗,基本掌握利用內(nèi)蒙古黃河灌區(qū)土默川分灌區(qū)典型粉質(zhì)土配制得水泥土的一些強度特性。(2)在普通水泥土基礎(chǔ)上單摻粉煤灰和脫硫石膏,研究其摻量對強度的影響規(guī)律。(3)通過正交試驗和補充試驗,研究復(fù)摻粉煤灰和脫硫石膏對其強度的影響規(guī)律,得出最優(yōu)配合比并進行驗證,建立強度預(yù)測模型。2、建立了一種全新的復(fù)合水泥土非線性彈性本構(gòu)模型,分析了其變形與破壞特征。(1)根據(jù)單軸受壓下復(fù)合水泥土全應(yīng)力-應(yīng)變曲線的特點,首次提出用生長函數(shù)logistic擬合曲線的上升段,采用復(fù)合雙曲線函數(shù)擬合曲線的下降段,建立分段非線性本構(gòu)模型,較傳統(tǒng)CSDC-2002模型擬合效果更好。(2)根據(jù)三軸受壓下復(fù)合水泥土偏應(yīng)力-軸向應(yīng)變曲線的特點,建立“三段法”非線性彈性模型,給出了完整的推導(dǎo)過程和參數(shù)計算過程。(3)研究了變形模量、破壞應(yīng)變與無側(cè)限抗壓強度的關(guān)系,并分析了單軸受壓與三軸受壓情況下復(fù)合水泥土的破壞形態(tài)。3、評價了復(fù)合水泥土材料的耐久性,開展了與普通水泥土耐久性的對比分析。(1)干濕和凍融循環(huán)試驗均表明復(fù)合水泥土的耐干濕循環(huán)能力和抗凍性能均優(yōu)于普通水泥土。(2)三溫凍融循環(huán)試驗表明復(fù)合水泥土的整體位移小于普通水泥土;當基層土料含水量接近最優(yōu)含水量時,疊合復(fù)合水泥土試樣的整體變形量最小,抗凍性能最佳。4、創(chuàng)新了復(fù)合水泥土材料的微結(jié)構(gòu)分析方法,研究了其固化機理和損傷特性。(1)提出了原子力顯微鏡AFM觀察水泥土材料樣品的制樣方法,將其用于微結(jié)構(gòu)的觀察;同時也利用場發(fā)射環(huán)境掃描電鏡觀察了非導(dǎo)電復(fù)合水泥土試樣的微結(jié)構(gòu)。(2)在微結(jié)構(gòu)分析的基礎(chǔ)上,探討了復(fù)合水泥土的固化機理;在單軸壓縮損傷試驗的基礎(chǔ)上,分析了復(fù)合水泥土的損傷演化規(guī)律,推導(dǎo)建立了復(fù)合水泥土在單軸壓縮條件下的彈塑性損傷模型。
[Abstract]:The study of durability and solidification mechanism of cement-soil is the key to popularize and apply cement-soil in the cold region of northern China. In view of the characteristics of low strength and poor durability of ordinary cement-soil, At the same time, in order to solve a large amount of industrial waste fly ash and desulphurization gypsum produced by coal-fired power plant in our region, a new kind of composite cement-soil material is put forward. The durability, damage characteristics and solidification mechanism of the composite are provided with theoretical basis and experimental data for its wide application in Inner Mongolia, and the strength prediction model of composite cement-soil is established. It is put forward that the test of unconfined compressive strength of ordinary cement-soil under different cement mixing ratio, different age, different specimen specification and molding method is carried out by the optimum mix ratio of each component material. Basically master some strength characteristics of cement soil prepared from typical silty soil in Tumechuan irrigation area of Inner Mongolia Yellow River Irrigation area) only add fly ash and desulphurized gypsum on the basis of ordinary cement soil. Through orthogonal and supplementary tests, the influence of fly ash and desulphurized gypsum on its strength is studied, and the optimum mix ratio is obtained and verified. A new nonlinear elastic constitutive model of composite cement-soil is established. The deformation and failure characteristics of composite cement-soil are analyzed according to the characteristics of stress-strain curve of composite cement-soil under uniaxial compression. For the first time, a piecewise nonlinear constitutive model is established by using the growth function logistic to fit the rising segment of the curve and the compound hyperbolic function to fit the descending section of the curve. According to the characteristics of stress-axial strain curve of composite cement-soil under triaxial compression, a "three-stage method" nonlinear elastic model is established, which is better than the traditional CSDC-2002 model. The relationship between deformation modulus, failure strain and unconfined compressive strength is studied. The failure mode of composite cement-soil under uniaxial compression and triaxial compression is analyzed, and the durability of composite cement-soil material is evaluated. A comparative analysis of durability of cement soil and ordinary cement soil was carried out. (1) dry wet and freeze-thaw cycle tests showed that the dry and wet cycle resistance and frost resistance of composite cement soil were superior to those of ordinary cement soil. 2) Three-temperature freeze-thaw cycle test showed that composite water was better than that of common cement soil. The whole displacement of soil is smaller than that of ordinary cement soil. When the moisture content of the base soil is close to the optimal water content, the composite cement-soil sample has the smallest overall deformation and the best frost resistance .4. the microstructural analysis method of the composite cement-soil material is innovated. The curing mechanism and damage characteristics of the cement soil were studied. (1) the method of atomic force microscope (AFM) was proposed to observe the sample of cement soil material, and the method was used to observe the microstructure of cement soil. At the same time, the microstructure of non-conductive composite cement-soil sample was observed by using field emission environment scanning electron microscope (SEM). On the basis of microstructure analysis, the solidification mechanism of composite cement-soil was discussed, and on the basis of uniaxial compression damage test, the solidification mechanism of composite cement-soil was discussed. The damage evolution law of composite cement-soil is analyzed and the elastic-plastic damage model of composite cement-soil under uniaxial compression is derived.
【學位授予單位】：內(nèi)蒙古農(nóng)業(yè)大學
【學位級別】：博士
【學位授予年份】：2015
【分類號】：TU43;TU472
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本文編號：1632531