本文關(guān)鍵詞： 鋅污染 紅粘土 水泥固化/穩(wěn)定 無側(cè)限抗壓強度 淋濾試驗 微觀孔隙 XRD分析　出處：《內(nèi)蒙古農(nóng)業(yè)大學》2017年碩士論文　論文類型：學位論文

【摘要】：鋅礦的開采、鍍鋅、儀器儀表及機械制造等工業(yè)活動,使土壤受到重金屬鋅的污染,其中紅粘土受到的鋅污染更為嚴重。為治理受到重金屬鋅污染的紅粘土,使用水泥固化法(S/S法)對污染土進行固化處理,研究處理后固化物的力學特性、工程特性、化學穩(wěn)定性及固化機理。為污染土固化物作為淺層地基或護岸等非敏感區(qū)域的建筑材料提供一定的基礎(chǔ)數(shù)據(jù),期望達到污染土治理及二次利用的目的。主要研究成果如下:(1)將硝酸鋅溶液與風干后紅粘土進行混合,配置不同濃度的人工污染土,摻入水泥經(jīng)不同養(yǎng)護齡期固化后,進行無側(cè)限抗壓強度試驗。研究了鋅濃度、水泥摻量和養(yǎng)護齡期對固化物無側(cè)限抗壓強度、破壞應(yīng)變及變形模量的影響;分析了各濃度固化物的應(yīng)力-應(yīng)變曲線;提出了鋅影響固化物力學特性的閾值濃度;探討了以鋅濃度、水泥摻量和養(yǎng)護齡期為影響因素的無側(cè)限強度預(yù)測方法。(2)通過對污染土固化物進行淋濾試驗,研究了不同鋅濃度、水泥摻量和養(yǎng)護齡期對固化物穩(wěn)定性的影響。分析了固化物穩(wěn)定性的影響因素;得出當水泥摻量10%時,鋅污染紅粘土固化物穩(wěn)定性較佳;提出固化過程中對于穩(wěn)定性起主要作用的是紅粘土對鋅的吸附,而水泥的水化反應(yīng)對重金屬鋅的包裹和禁錮起著協(xié)同作用的觀點。(3)通過對固化物體積、含水量和質(zhì)量的測定。研究各影響因素對固化物含水率、體積和質(zhì)量的影響規(guī)律;提出高濃度的鋅可以改變紅粘土的性質(zhì),使紅粘土出現(xiàn)親水性,導致固化物在標準養(yǎng)護情況下吸水膨脹;得出提高固化物的水泥摻量,可有效減小固化物膨脹,提高其無側(cè)限抗壓強度,增加受污染的紅粘土的工程適用性的結(jié)論;提出了根據(jù)固化物干質(zhì)量的變化規(guī)律分析固化物水化反應(yīng)程度的方法。(4)采用壓汞試驗研究了固化物的孔結(jié)構(gòu)。從細觀和微觀角度探討了固化物的固化機理。(5)通過對固化物進行XRD等試驗,研究不同養(yǎng)護階段固化物的化學生成物,分析了其各階段固化物的化學反應(yīng)機理。發(fā)現(xiàn)固化物養(yǎng)護后期會產(chǎn)生Si02結(jié)晶物,提出在養(yǎng)護后期Si02結(jié)晶會起到骨料作用與水化反應(yīng)生成的水合硅酸鈣互相膠結(jié)是固化物后期強度的主要來源的觀點。
[Abstract]:Industrial activities such as zinc mining, galvanizing, instrumentation and mechanical manufacturing have made the soil polluted by heavy metal zinc, among which the red clay is more seriously polluted by zinc. In order to control the red clay contaminated by heavy metal zinc, The cement curing method is used to cure the contaminated soil, and the mechanical and engineering properties of the cured soil after treatment are studied. Chemical stability and solidification mechanism. Provide certain basic data for contaminated soil solidification as building materials in non-sensitive areas such as shallow foundation or bank revetment. The main research results are as follows: 1) mixing zinc nitrate solution with air-dried red clay, mixing different concentrations of artificially contaminated soil, and mixing cement with cement after curing at different curing ages. The effects of zinc concentration, cement content and curing age on the unconfined compressive strength, failure strain and deformation modulus of the cured compounds were studied, and the stress-strain curves of the solidified compounds were analyzed. The threshold concentration of zinc affecting the mechanical properties of solidified soils is put forward, and the prediction method of unconfined strength, which takes zinc concentration, cement content and curing age as the influencing factors, is discussed. Different zinc concentrations are studied through leaching tests on the solidified compounds of contaminated soil. The influence of cement content and curing age on the stability of solidified clay was analyzed, and the results showed that the stability of zinc contaminated red clay was better when the cement content was 10%. It is suggested that the adsorption of zinc by red clay is the main factor in the stability of the solidification process, while the hydration reaction of cement plays a synergistic role on the encapsulation and confinement of heavy metal zinc. Determination of water content and mass. The effect of various factors on the water content, volume and mass of cured compounds was studied, and it was suggested that high concentration of zinc could change the properties of red clay and make red clay hydrophilic. It is concluded that increasing the cement content of cured compounds can effectively reduce the expansion of solidified compounds, increase their unconfined compressive strength and increase the engineering applicability of contaminated red clay. The method of analyzing the degree of hydration reaction of cured compounds according to the variation law of dry mass of solidified compounds was put forward. The pore structure of cured compounds was studied by mercury injection test. The solidification mechanism of cured compounds was discussed from the microcosmic and microcosmic angles. The XRD and other tests were carried out on the solidified compounds. The chemical products of solidified compounds in different curing stages were studied, and the chemical reaction mechanism of solidified compounds in each stage was analyzed. It was found that Si02 crystals would be produced in the later curing stages of cured compounds. It is pointed out that the hydration of calcium silicate hydrated during the later curing period is the main source of the later strength of the solidified compound, and the crystallization of Si02 will act as aggregate and the hydration reaction will result in the mutual cementation of calcium silicate hydrate.
【學位授予單位】：內(nèi)蒙古農(nóng)業(yè)大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：X53

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