盾构隧道壁后新型注浆材料的试验研究

发布时间：2018-11-25 14:14

【摘要】：随着我国国民经济和社会发展,城镇化进程加快的需要,城市及城际轨道交通正在快速发展。地铁隧道工程项目的不断增多,伴随着注浆材料的大量使用,这就要求注浆材料具有优异的胶凝性能和力学性能,并且对体积稳定性、抗渗性能、抗水溶蚀性能等耐久性能提出了一定的要求。本文提出了一种新型水泥基注浆材料,该种新型注浆材料具有速凝、早强、结石率高、经济环保等特点。本文以新型注浆材料为研究对象,从材料的胶凝性能、力学性能、耐久性能以及对耐久性能评价进行试验研究,主要研究成果和结论如下:通过试验分析了不同水灰比的新型注浆材料、纯水泥浆液、水泥-水玻璃和胶砂四种材料的胶凝性能。结果表明新型注浆材料的胶凝时间可以自由调节,无泌水现象,结石率为100%,pH10,不会对衬砌管片造成腐蚀,满足使用要求;通过试验分析了不同水灰比的新型注浆材料、纯水泥浆液、水泥-水玻璃和胶砂四种材料的力学性能,包括抗压强度和三轴压缩强度并结合SEM进行微观结构分析。试验结果得出新型注浆材料抗压强度具有早强性、三轴压缩强度随围压增大残余强度也增大的特点,并通过SEM微观检测手段,结合对抗压强度研究,对比分析四种材料类型在28 d养护龄期的水化产物及微观形貌。通过耐久性试验分析了新型注浆材料、纯水泥浆液、水泥-水玻璃和胶砂材料的抗地下水溶蚀性能、抗渗性能和体积稳定性能。阐述了水泥类注浆材料的水化固结原理,分析总结了注浆材料在地下水溶蚀条件下抗压强度变化以及质量损失情况,并通过纯水浸泡试验,分析注浆材料的电导率和溶出物质总量的变化过程;对于注浆材料的抗渗性能,采用渗透系数和抗渗压力两种指标来表征,结果表明新型注浆材料28 d渗透系数均能达到10-8级,表明有良好的抗渗性能;研究注浆材料的体积稳定性,包括干缩性能和早期开裂性能,结果表明新型注浆材料28d干缩值是纯水泥浆液的1/23,是水泥-水玻璃的1/31,是胶砂材料的1/16,新型注浆材料出现裂缝的时间为12 h,晚于其他材料类型,在1 d和7 d时的裂缝宽度分别小于0.4 mm和3.5 mm,小于其他材料类型,表明新型注浆材料有着优异的体积稳定性能。通过多因素模糊综合评定理论评价四种注浆材料的耐久性能。本文选择注浆材料抗水溶蚀性能、抗水渗透性能以及体积稳定性能作为影响因素,懫用层次分析法确定各因素的权重,结果表明新型注浆材料耐久性评价结果为优秀,纯水泥浆液为一般,水泥-水玻璃材料为差,胶砂材料为良好。
[Abstract]:With the development of national economy and society and the need of accelerating urbanization, urban and intercity rail transit is developing rapidly. With the increasing number of subway tunnel engineering projects and the extensive use of grouting materials, it is required that the grouting materials have excellent cementing and mechanical properties, and have good volume stability and impermeability. Some requirements for durability such as water corrosion resistance are put forward. In this paper, a new cement-based grouting material is proposed, which has the characteristics of quick solidification, early strength, high stone rate, economic and environmental protection, etc. In this paper, a new type of grouting material is studied in terms of its cementing properties, mechanical properties, durability and durability evaluation. The main research results and conclusions are as follows: the cementitious properties of new grouting materials with different water-cement ratio, pure cement paste, cement-water glass and cement sand are analyzed. The results show that the cementing time of the new grouting material can be adjusted freely, there is no bleeding phenomenon, the calculi rate is 100 and pH 10, and it will not cause corrosion to the lining segments and meet the requirements of application. The mechanical properties, including compressive strength and triaxial compressive strength, of new grouting materials with different water-cement ratio, pure cement slurry, cement-water glass and cement-sand were analyzed. The microstructure was analyzed with SEM. The test results show that the compressive strength of the new grouting material has early strength, and the triaxial compressive strength increases with the increase of confining pressure, and the compressive strength is studied by means of SEM microcosmic test. The hydration products and micromorphology of four kinds of materials at the age of 28 days were compared and analyzed. The corrosion resistance of groundwater, impermeability and volume stability of new grouting material, pure cement slurry, cement-water glass and cement sand were analyzed by durability test. The principle of hydration and consolidation of cement grouting materials is expounded. The changes of compressive strength and mass loss of grouting materials under groundwater dissolution are analyzed and summarized. The change process of electrical conductivity and total amount of dissolved matter of grouting material is analyzed. Permeability coefficient and impermeability pressure were used to characterize the impermeability of grouting material. The results showed that the permeability coefficient of the new grouting material could reach 10-8 grade in 28 days, which indicated that the new grouting material had good impermeability. The volume stability of grouting material, including dry shrinkage property and early cracking property, was studied. The results show that the new grouting material's dry shrinkage value in 28 days is 1 / 23 of pure cement slurry, 1 / 31 of cement-water glass, and 1 / 16 of cement sand material. The crack time of the new grouting material is 12 h, which is later than that of other material types. The crack width of 1 d and 7 d is less than 0.4 mm and 3.5 mm, respectively, which is smaller than that of other material types. It shows that the new grouting material has excellent volume stability. The durability of four grouting materials was evaluated by multi-factor fuzzy comprehensive evaluation theory. In this paper, the water corrosion resistance, water permeability and volume stability of grouting materials are selected as the influencing factors, and the weight of each factor is determined by analytic hierarchy process. The results show that the durability evaluation results of new grouting materials are excellent. The pure cement slurry is general, the cement-water glass material is poor, the cement sand material is good.
【学位授予单位】：中国矿业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U455.43;U456

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