糯米灰浆对遗址土的加固效果及机理研究

发布时间：2018-06-02 06:09

本文选题：土遗址 + 糯米浆　；参考：《兰州大学》2017年硕士论文

【摘要】：作为文物重要组成部分的土遗址具有重要的历史价值、艺术价值和科学价值。由于土遗址大多遗存于自然条件下,土遗址易受到环境因素的物理、化学和生物等破坏作用。因此,我们必须以“保护为主、抢救第一、合理利用、加强管理”为首要原则采取保护措施以便使土遗址能够长期地进行科学研究以及参观展出。在西北地区,黄土大量赋存并作为主要材料用于土遗址建筑,所以修复被破坏的土遗址也需使用黄土。而黄土具有以粉粒为主、耐性不良等独特的工程特性,必须经过改性后才能用于土遗址修复工程中。目前,用于文物保护的加固材料主要包括无机材料、有机材料以及有机-无机复合材料。无机材料中石灰作为加固剂具有良好的改良效果和实际工程经验。经调查发现使用糯米浆为加固剂的灰浆或三合土作为建筑材料的土遗址具有非常好的强度特性和耐久性。为更加科学合理地使用和发挥糯米浆和石灰的优势,并应用到土遗址修复工程中,本文研究了糯米灰浆固化黄土的加固效果以及加固机理。本文设定0%、1%、2%、3%、4%、5%浓度的糯米浆以及0%、2%、4%、6%、8%、10%灰土比的石灰加固试样,然后测试其强度特性、耐水性、色差、透气性以及耐盐析性,评价不同配比糯米灰浆的加固效果。然后通过扫描电镜SEM观察试样的颗粒形态、接触关系以及孔隙结构,揭示糯米灰浆加固黄土的反应机理。根据上述实验及数据分析,本文主要得出以下结论:(1)糯米浆及石灰加入黄土后,可有效提高黄土的力学性能、耐水性和耐盐性,其强度最大增长超过4倍,但降低了试样的透气性。同时对颜色变化影响不大。(2)随着掺入石灰的增加,固化黄土的无侧限抗压强度逐渐增大,耐水性逐渐增强,耐盐析性增强,透气性减弱。但当灰土比超过8%时,经盐析破坏后试样的残余强度有所降低。(3)随掺入糯米浆浓度的增大,固化黄土的无侧限抗压强度先增大后减小,经盐破坏后试样的残余强度同样先增强后降低,以糯米浆浓度为3%的试样强度最大;试样的耐水性变化不大,透气性先减小后增加;糯米浆浓度大于3%时,耐盐破坏性明显减弱。(4)根据本论文指标综合评价固化黄土的最优灰土比为8%,最优糯米浆浓度为3%。(5)糯米灰浆对黄土的加固机理主要包括石灰与黄土的反应以及糯米浆通过调控石灰的结晶对黄土的改良作用。石灰与黄土的反应主要是离子交换反应、结晶作用、胶结作用与火山灰反应。糯米浆的加固作用主要是调控碳酸钙晶体的形态大小以及钙离子的排布,进而影响土颗粒的结构和胶结能力。
[Abstract]:As an important part of cultural relics, earthen sites have important historical value, artistic value and scientific value. Because most of the earth remains in natural conditions, earth sites are vulnerable to the physical, chemical and biological destruction of environmental factors. Therefore, we must take "protection first, rescue first, reasonable use, strengthen management" as the first principle to take protective measures so that the earthen sites can carry out scientific research and visit exhibitions for a long time. In Northwest China, loess exists in large quantities and is used as the main material in earthen sites, so it is also necessary to repair the damaged earthen sites. Loess has special engineering characteristics, such as silt particles, poor tolerance and so on, which must be modified before it can be used in the restoration of earthen sites. At present, the reinforcement materials for cultural relic protection mainly include inorganic materials, organic materials and organic-inorganic composite materials. Lime as reinforcement agent in inorganic materials has good improvement effect and practical engineering experience. Through investigation, it is found that mortar with glutinous rice paste as reinforcement agent or soil site with trinity soil as building material has very good strength characteristics and durability. In order to use and exert the advantages of glutinous rice paste and lime more scientifically and reasonably, and to be applied to the restoration of earthen sites, the reinforcement effect and reinforcement mechanism of glutinous rice mortar solidified loess are studied in this paper. In this paper, we set up 5% glutinous rice paste and 10% lime-soil ratio, then test its strength, water resistance, color difference, air permeability and salt-out resistance, and evaluate the reinforcement effect of different proportions of glutinous rice mortar. Then the particle morphology, contact relationship and pore structure of the samples were observed by scanning electron microscope (SEM) to reveal the reaction mechanism of glutinous rice mortar in strengthening loess. Based on the above experiments and data analysis, the following conclusions are drawn in this paper: (1) when the glutinous rice paste and lime are added to the loess, the mechanical properties, water resistance and salt resistance of the loess can be improved effectively, and the maximum increase of the strength is more than 4 times. However, the permeability of the sample was decreased. At the same time, with the increase of lime, the unconfined compressive strength, water resistance, salt-out resistance and air permeability of solidified loess gradually increased. However, when the lime-soil ratio is over 8, the residual strength of the sample after salting-out damage decreases with the increase of glutinous rice slurry concentration, the unconfined compressive strength of the solidified loess increases first and then decreases. After salt destruction, the residual strength of the sample also increased first and then decreased. The strength of the sample with 3% glutinous rice pulp concentration was the largest; the water resistance of the sample changed little, but the permeability decreased first and then increased, and when the glutinous rice pulp concentration was greater than 3%, According to the index of this paper, the optimum lime-soil ratio of solidified loess is 8, and the optimum glutinous rice slurry concentration is 30.The reinforcement mechanism of glutinous rice mortar to loess mainly includes the reaction between lime and loess and glutinous rice. Slurry improves loess by regulating the crystallization of lime. The reaction between lime and loess is mainly ion-exchange reaction, crystallization, cementation and pozzolanic reaction. The strengthening effect of glutinous rice paste is mainly to regulate the shape and size of calcium carbonate crystal and the arrangement of calcium ions, thus affecting the structure and cementation ability of soil particles.
【学位授予单位】：兰州大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU-87

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