| 项国圣,卞云飞,付文青,周殷康.热-碱作用对压实膨润土抗剪性能的影响[J].安徽建筑大学学报,2024,32(6):8-14 |
| 热-碱作用对压实膨润土抗剪性能的影响 |
| Study on Effect of Temperature-alkali Interaction on the Shear Properties of Compacted Bentonite |
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| DOI： |
| 中文关键词: 恒体积 温度 碱溶液 膨润土 抗剪性能 |
| 英文关键词: constant volume temperature alkali solution bentonite shear properties |
| 基金项目:安徽省自然科学基金项目（2208085MD98、2108085QD168） |
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| 中文摘要: |
| 通过模拟压实膨润土在核废料处置库中的热-碱环境，开展恒体积饱和膨润土的不排水直剪试验，研究在25 ℃、40 ℃、60 ℃温度下，NaOH、KOH溶液对压实膨润土抗剪性能的影响，并借助 SEM电镜试验分析膨润土的微观形貌变化，探究其作用机理。结果表明：热-碱环境中膨润土的剪应力变化稳定，并出现应变软化特征。在浓度由0.1 mol/L提高到1.0 mol/L，温度由25 ℃提高到60 ℃时，膨润土的剪应力和抗剪强度增强，黏聚力与内摩擦角增大。溶液浓度的提高加剧阳离子降低土体颗粒间斥力，改变颗粒内部微观排列顺序；温度的提高会提高水分子活跃程度，使土体颗粒间弱结合水减少，晶层收缩，骨架强度增强。此外，温度提高还促进碱溶液与土体颗粒的反应，进一步增加黏聚力和内摩擦角。不同碱溶液的阳离子交换反应导致 K+与膨润土产生强度更高的 K-键，使同条件下KOH溶液对膨润土剪应力和抗剪强度的提高程度强于NaOH溶液，膨润土的黏聚力与内摩擦角同样增加。 |
| 英文摘要: |
| By simulating the temperature-alkali environment of compacted bentonite in the nuclear waste repository, undrainedstraight shear test on constant volume saturated bentonite were carried out, research in 25 ℃、40 ℃、60℃ temperature, NaOH, KOHsolution on the shear resistance of compacted bentonite, with the help of SEM microscope test to analyze bentonite microscopic morphologicalchanges, and explore the mechanism of its action. The results show that the shear stress of bentonite samples in the temperature-alkalienvironment is relatively stable and all of them show strain softening characteristics. The concentration was increased from 0.1 mol/L to1.0 mol/L, and the temperature was increased from 25 ℃ to 60 ℃, the shear stress and shear strength of bentonite were enhanced, alongwith the cohesion and internal friction angle; the increase in solution concentration would aggravate the degree to which cations wouldreduce the repulsive force between the particles of the soil body and alters the microstructural arrangement of particles; the increase intemperature increases the activity of water molecules, which reduces the weakly bound water between soil particles and increases thestrength of the shrinkage skeleton of the crystal layer, in addition to promoting the reaction between the alkali solution and the soil particles,which leads to an increase in the cohesion and the angle of internal friction. Cation exchange reaction between different alkali solutions,resulting in K+ and bentonite to produce a higher strength of the K-linkages, so that under the same conditions of KOH solution on thebentonite shear stress and shear strength to improve the degree stronger than NaOH solution, bentonite cohesion and the angle ofinternal friction is also produced to improve. |
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