基于动态振荡剪切的砒砂岩浆体流变行为研究
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周琳(1997—),女,河南南阳人,博士研究生,主要从事土壤结构稳定性研究。E-mail:zhoulin20@mails.ucas.ac.cn

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P642.2

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国家自然科学基金项目(41977024)


Study of the Rheological Behavior of Pisha Sandstone Slurry Based on Dynamic Oscillatory Shear
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    摘要:

    [目的] 随着全球变暖及强降水极端事件频发,砒砂岩区滑塌泥流灾害可能将不断增加。为探明水-土互馈作用如何导致脆弱岩土松动变形进而发展为泥流,系统认识其演化过程的关键科学问题。[方法] 以4种典型砒砂岩为研究对象,采用流变学方法,开展动态振荡剪切下砒砂岩浆体的流变特性研究,探索砒砂岩浆体的液化过程及流变特性。[结果] (1)随着剪切应变增加,4种砒砂岩浆体储能模量和损耗模量减小,表现出应变变稀特点。(2)在含水率较低(w<50%)的样品中,紫、棕色砒砂岩浆体与红、白色砒砂岩浆体相比,线性黏弹区的应力和应变更大。在含水率较高(w≥50%)的样品中,红、白色砒砂岩浆体与紫、棕色砒砂岩浆体相比,流动点的应力和应变更大。(3)随含水率增加,4种砒砂岩浆体的储能模量和损耗模量降低,线性黏弹区的应力和应变降低。[结论] 细颗粒物质可增加浆体在线性黏弹区的抗剪强度和弹性,但细颗粒浆体受含水率影响较大,水分加入后,浆体结构破坏、抵抗变形的能力立即减弱,同时,更容易发生相态转变。粗颗粒的存在使浆体非线性黏弹区弹性主导的范围增大,阻碍浆体的相态转变。该研究结果为砒砂岩区泥流灾害的认识和防治提供一定的科学基础。

    Abstract:

    [Objective] With global warming and increased occurrences of heavy precipitation, the frequency of landslide mudflow disasters in the Pisha sandstone area will increase significantly. Understanding how water-soil interaction affect the loosening and deformation of fragile soils, ultimately leading to mudflow development, is a crucial scientific question in the evolutionary process. [Methods] This study focuses on investigating the rheological properties of Pisha sandstone (PS) slurry using a rheological method that involves dynamic oscillatory shear. The primary objective is to examine the liquefaction process and initial rheological properties of PS slurry. [Results] (1) With the increase of shear strain, the energy storage modulus (G') and loss modulus (G″) of the four PS slurries decreased and exhibited strain thinning characteristics. (2) In the samples with lower water content (w<50%), the stress and strain in the linear viscoelastic region (LVE) of purple and brown PS slurries were larger than red and white PS slurries. In the samples with higher water content (w≥50%), the stress and strain at the flow point of red and white PS slurries were larger than purple and brown PS slurries. (3) With increasing water content, G' and G″ of the four PS slurries decreased, and the stress and strain in the LVE decreased. [Conclusion] Fine particles could increase the shear strength and elasticity of the slurry in the LVE, but the fine-grained slurry was more affected by the moisture content, and the ability of the slurry structure to destroy and resist deformation was weakened immediately after the addition of water, while the phase transition was more likely to occur. The presence of coarse particles increased the extent of the elastic dominance of the nonlinear viscoelastic region and hindered the phase transition of the slurry. The results of the study can provide scientific basis for further mudflow research and disaster control in the Pisha sandstone area.

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周琳, 胡斐南, 许晨阳, 杜伟, 张亚楠.基于动态振荡剪切的砒砂岩浆体流变行为研究[J].水土保持学报,2024,38(3):45~53

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  • 收稿日期:2023-08-24
  • 最后修改日期:2023-12-15
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  • 在线发布日期: 2024-07-03
  • 出版日期: 2024-06-28
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