自凝灰浆防渗性能提高的试验研究
发布时间：2018-11-26 07:24
【摘要】：对于未采取任何防渗措施的早期建成的填埋场,或者防渗处理不完善的老填埋场常常有必要使用垂直防渗墙来补救。自凝灰浆防渗墙是一种垂直防渗墙,具有较低的弹性模量、适应地基变形能力强、施工工艺简单、成本廉价等优点,经常被应用在环境保护类工程。但在自凝灰浆的一些现实应用中,常呈现出墙体的渗透系数不满足设计要求的情形,因此,提高自凝灰浆固结体的防渗性能,研究其力学性能和微观机理,对了解和应用这类墙体材料具有指导性意义。本文从宏观和微观两个层面进行研究,对自凝灰浆进行了室内配合比的防渗性能、力学性能和孔隙结构的试验研究,试图提高自凝灰浆固结体的防渗性能,得到优化配合比,通过室内试验,得到了一些有价值的结论和结果:(1)针对自凝灰浆原材料的不同种类和数量设计了三组不同的配合比,利用ST55-2改进型渗透仪测定了它们的7d和28d的渗透系数,讨论并阐明了膨润土、粉煤灰及碱激发剂等材料对渗透系数的影响,研究了龄期对防渗性能的作用,得到了优化后的配合比配方,粉煤灰在无碱激发时,最佳掺量为230~250g/1000g水,渗透系数最低可达1.99×10-7cm/s;粉煤灰在有碱激发剂的环境中,渗透系数会降低;1000g水中,NaOH和Na2SiO3加量各50g,膨润土加量180~200g,粉煤灰加量350g,水泥200g时可获得渗透系数在1×10-7cm/s以下的自凝灰浆固结体;28d的养护龄期比7d的养护龄期的固结体防渗性能要好很多。(2)按照优化配合比配制试块,利用电子万能试验机对固结体进行力学试验,得到了固结体的应力-应变关系曲线和抗压强度及变形模量,其强度最高可达2.42MPa,变形模量最高可达60.15MPa。(3)通过电子显微镜对固结体进行图像观察,并使用ToupView软件对固结体的孔隙结构特征进行分析,得到自凝灰浆固结体的临界孔径大致在23~80μm之间,并从微观层面简要分析了水泥-膨润土的反应机理和粉煤灰受碱激发的模型,对固结体的孔隙与防渗性的关系进行了分析和探讨。
[Abstract]:It is often necessary to use vertical cutoff walls for early constructed landfills without any seepage control measures or for old landfills that are not well disposed of seepage. Self-mortar impervious wall is a kind of vertical impervious wall, which has the advantages of low elastic modulus, strong ability to adapt to the deformation of foundation, simple construction technology, low cost and so on. It is often used in environmental protection projects. However, in some practical applications of the self-coagulating mortar, the permeability coefficient of the wall often does not meet the design requirements. Therefore, the anti-seepage performance of the self-coagulating mortar consolidation body is improved, and its mechanical properties and microscopic mechanism are studied. It is instructive to understand and apply this kind of wall material. In this paper, the anti-seepage performance, mechanical properties and pore structure of self-coagulating mortar were studied from macroscopic and microscopic aspects, and the optimum mix ratio was obtained by improving the anti-seepage performance of self-coagulating mortar consolidation body. Through the laboratory test, some valuable conclusions and results are obtained: (1) three groups of different mix ratios are designed for different kinds and quantity of raw materials of self-coagulating mortar. The permeability coefficients of 7 d and 28 d were measured by ST55-2 modified osmometer. The effects of bentonite, fly ash and alkali activator on the permeability coefficient were discussed, and the effect of age on impermeability was studied. The optimized formula is obtained. When the fly ash is excited without alkali, the best dosage is 230~250g/1000g water, and the lowest permeability coefficient can be up to 1.99 脳 10 ~ (-7) cm ~ (-1) 路s ~ (-1) 路L ~ (-1) 路L ~ (-1); In the environment with alkali activator, the permeability coefficient of fly ash will be decreased, the addition of NaOH and Na2SiO3 in 1000g water, the addition of bentonite at 180g, the addition of fly ash by 350g, and the cement by 200g, the self-coagulating mortar consolidation body with permeability coefficient below 1 脳 10-7cm/s can be obtained. The curing age of 28 days is much better than that of the curing age of 7 days. (2) according to the optimized mix ratio, the mechanical tests of the consolidation body are carried out by using the electronic universal testing machine. The stress-strain relationship curve, compressive strength and deformation modulus of the consolidated body are obtained. The maximum strength and deformation modulus of the consolidated body are 2.42 MPA and 60.15 MPA respectively. (3) the image of the consolidated body is observed by electron microscope. The pore structure characteristics of consolidation body were analyzed by ToupView software, and the critical pore size of the consolidation body was about 2380 渭 m. The reaction mechanism of cement-bentonite and the model of fly ash excited by alkali were briefly analyzed from the microcosmic level. The relationship between porosity and impermeability of consolidation body is analyzed and discussed.
【学位授予单位】：中国地质大学(北京)
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU57
本文编号：2357773
[Abstract]:It is often necessary to use vertical cutoff walls for early constructed landfills without any seepage control measures or for old landfills that are not well disposed of seepage. Self-mortar impervious wall is a kind of vertical impervious wall, which has the advantages of low elastic modulus, strong ability to adapt to the deformation of foundation, simple construction technology, low cost and so on. It is often used in environmental protection projects. However, in some practical applications of the self-coagulating mortar, the permeability coefficient of the wall often does not meet the design requirements. Therefore, the anti-seepage performance of the self-coagulating mortar consolidation body is improved, and its mechanical properties and microscopic mechanism are studied. It is instructive to understand and apply this kind of wall material. In this paper, the anti-seepage performance, mechanical properties and pore structure of self-coagulating mortar were studied from macroscopic and microscopic aspects, and the optimum mix ratio was obtained by improving the anti-seepage performance of self-coagulating mortar consolidation body. Through the laboratory test, some valuable conclusions and results are obtained: (1) three groups of different mix ratios are designed for different kinds and quantity of raw materials of self-coagulating mortar. The permeability coefficients of 7 d and 28 d were measured by ST55-2 modified osmometer. The effects of bentonite, fly ash and alkali activator on the permeability coefficient were discussed, and the effect of age on impermeability was studied. The optimized formula is obtained. When the fly ash is excited without alkali, the best dosage is 230~250g/1000g water, and the lowest permeability coefficient can be up to 1.99 脳 10 ~ (-7) cm ~ (-1) 路s ~ (-1) 路L ~ (-1) 路L ~ (-1); In the environment with alkali activator, the permeability coefficient of fly ash will be decreased, the addition of NaOH and Na2SiO3 in 1000g water, the addition of bentonite at 180g, the addition of fly ash by 350g, and the cement by 200g, the self-coagulating mortar consolidation body with permeability coefficient below 1 脳 10-7cm/s can be obtained. The curing age of 28 days is much better than that of the curing age of 7 days. (2) according to the optimized mix ratio, the mechanical tests of the consolidation body are carried out by using the electronic universal testing machine. The stress-strain relationship curve, compressive strength and deformation modulus of the consolidated body are obtained. The maximum strength and deformation modulus of the consolidated body are 2.42 MPA and 60.15 MPA respectively. (3) the image of the consolidated body is observed by electron microscope. The pore structure characteristics of consolidation body were analyzed by ToupView software, and the critical pore size of the consolidation body was about 2380 渭 m. The reaction mechanism of cement-bentonite and the model of fly ash excited by alkali were briefly analyzed from the microcosmic level. The relationship between porosity and impermeability of consolidation body is analyzed and discussed.
【学位授予单位】：中国地质大学(北京)
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU57
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