本文選題：微生物灌漿 + 高強微生物砂漿�。� 參考：《清華大學》2013年博士論文

【摘要】：微生物灌漿加固劣化砌體結(jié)構(gòu)是在不適合使用石灰、水泥和環(huán)氧樹脂等傳統(tǒng)灌漿材料情況下，在被加固空腔內(nèi)，原位填充顆粒，使其作為加固材料的骨架，并通過注入微生物和膠凝溶液的方法，在填充顆�？紫秲�(nèi)誘導生成碳酸鈣，膠凝顆粒，形成具有一定強度的微生物砂漿體。本研究主要通過沙柱灌漿模型實驗，系統(tǒng)地研究了影響形成微生物砂漿強度的主要因素，并結(jié)合微生物加固簡化模型、現(xiàn)場灌漿實驗和理論模擬分析，找到了制備高強度微生物砂漿的方法，并第一次對各強度等級微生物砂漿的材料、力學性能進行系統(tǒng)、全面的測試與分析，，為微生物灌漿技術應用于高質(zhì)量磚石砌體文物建筑加固，奠定了堅實的實驗和理論基礎。本文主要研究工作和貢獻如下： 首先通過對巴氏芽孢八疊球菌野生株的亞硝基胍誘變、篩選，得到該菌株的誘變株，使其增殖能力和產(chǎn)脲酶能力相對野生株均有所提高，且不同批次菌液脲酶活性離散性較小，可以穩(wěn)定遺傳誘變后的特性。同時，從土壤中分離得到耐受高尿素濃度、高鈣離子濃度的產(chǎn)脲酶菌株，其中的UR49D在脲酶活性和單體酶活性方面與巴氏芽孢八疊球菌野生株具有可比性，且原位酶活性保持能力較高。 其次，通過沙柱實驗優(yōu)化填充顆粒粒徑、菌株類型、膠凝液濃度、灌漿次數(shù)等可控灌漿參數(shù)，有效控制形成微生物砂漿的單軸抗壓強度，并成功得到單軸抗壓強度在2MPa到55MPa不同強度的微生物砂漿樣品。 接著，通過對這些微生物砂漿的單軸抗壓、劈裂抗拉、循環(huán)荷載抗壓、單壓疲勞等力學性能測試，以及其材料膠凝礦物晶體結(jié)構(gòu)和孔徑分布的分析，表明這種新型材料相對同等單軸抗壓強度的水泥-石灰混合砂漿而言，具有更高的劈裂抗拉強度，較好的延性和耐久性好，是一種較理想的原位加固劣化砌體結(jié)構(gòu)灌漿新材料。 此外，通過簡化加固模型實驗和現(xiàn)場試驗研究，可以發(fā)現(xiàn)微細裂縫的微生物灌漿還有一定困難，而缺失修復和空鼓填充加固相對容易實施；室外施工時，還應注意避免冬季低溫施工，以確保微生物活動不受低溫環(huán)境影響。 最后，通過適當簡化，可以對相對復雜的顆粒體系微生物砂漿形成過程進行數(shù)學建模，并可以實現(xiàn)對沙柱微生物灌漿過程中碳酸鈣生成量、尿素濃度、孔隙率等參數(shù)變化情況的一維有限元程序模擬，為微生物灌漿提供了一定的理論基礎。
[Abstract]:When the traditional grouting materials such as lime, cement and epoxy resin are not suitable for the reinforcement of the masonry structure by microbial grouting, the particles are filled in the strengthened cavity in situ so that it can be used as the skeleton of the reinforcing material. By injecting microorganism and cementing solution, calcium carbonate was induced in the pore of filling particles to form microorganism mortar with certain strength. In this study, the main factors influencing the strength of microbial mortar were systematically studied through the sand column grouting model experiment, and combined with the simplified model of microbial reinforcement, field grouting experiment and theoretical simulation analysis. The preparation method of high strength microbial mortar was found, and the material and mechanical properties of each strength grade microbial mortar were systematically tested and analyzed for the first time. It lays a solid experimental and theoretical foundation for the application of microbial grouting technology to the reinforcement of high quality masonry cultural relics. The main work and contributions of this paper are as follows: firstly, the mutant strain of Bacillus pasteuris was obtained by mutagenesis of nitrosoguanidine. The proliferative ability and urease production ability were improved compared with wild plants, and the dispersion of urease activity in different batches of bacteria was small, which could stabilize the characteristics after genetic mutation. At the same time, urease producing strains with high urea concentration and high calcium concentration were isolated from soil. The urease activity of UR49D was comparable with that of wild strain of Bacillus pasteuris in urease activity and monomer enzyme activity. And the in situ enzyme activity retention ability is higher. Secondly, the parameters of filling particle size, strain type, gel concentration and grouting times were optimized by sand column experiment to effectively control the uniaxial compressive strength of microbial mortar. The samples of microbial mortar with uniaxial compressive strength ranging from 2 MPA to 55 MPA were obtained successfully. Then, the mechanical properties of the microorganism mortar, such as uniaxial compressive resistance, splitting tensile resistance, cyclic load compression resistance, single pressure fatigue, and the crystal structure and pore size distribution of the cemented mineral are analyzed. The results show that the new material has higher splitting tensile strength, better ductility and durability than cement lime mixed mortar with the same uniaxial compressive strength. It is an ideal new material for in-situ strengthening and deterioration masonry structure grouting. In addition, through simplified reinforcement model experiments and field experiments, it can be found that there are some difficulties in microbial grouting of micro-cracks, but it is relatively easy to implement defect repair and empty drum filling reinforcement. We should also avoid low temperature construction in winter to ensure microorganism activity is not affected by low temperature environment. Finally, through proper simplification, the formation process of microbial mortar in relatively complex granular system can be modeled mathematically, and the amount of calcium carbonate and the concentration of urea during microbial grouting of sand column can be realized. The one-dimensional finite element program simulation of porosity and other parameters provides a theoretical basis for microbial grouting.
【學位授予單位】：清華大學
【學位級別】：博士
【學位授予年份】：2013
【分類號】：TU578.1

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