Fine particle loss in soil is one of the main causes of slope instability and geotechnical structure failure. Loss of fines can cause instability in granular assembles by changing the fabric and microstructure of the sample. However, real-time monitoring of the evolution of mechanical behavior in granular soils during the particle loss process is still poorly explored. This study presents a novel approach by simulating fine particle loss through salt dissolution in ring-shear tests, offering real-time insights into the mechanical evolution of granular soils under realistic stress conditions. Meanwhile, the shear resistance, shear displacement, vertical displacement, salt content, and acoustic emissions were simultaneously recorded. The test results showed that the instability of the sample was triggered by the loss of fine particles. With a gradual loss of fine particles, both the vertical and shear deformations and the void ratio increased. The evolution of shear resistance in the sample can be divided into three stages: stress weakening, then strengthening, and finally recovery to the initial value. We infer that the evolution of shear resistance originated from the collapse and rearrangement of its granular fabric and microstructure. Additional evidence for this hypothesis was provided by high-frequency acoustic emissions (approximately 150 kHz), suggesting buckling of the force chains accompanying the particle loss process. Furthermore, the sample experienced greater shear deformations and stress weakening that developed under a larger initial fine content or a higher normal stress. This finding may provide valuable insights into the mechanical behavior of granular soil during the fine particle loss process.

中文翻译：

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盐溶模拟细颗粒损失过程中颗粒土力学行为的演变：来自环剪切试验的见解


土体中细颗粒损失是导致边坡失稳和岩土结构破坏的主要原因之一。细粉损失会改变样品的结构和微观结构，从而导致颗粒组合物不稳定。然而，在颗粒损失过程中对颗粒土壤中力学行为演变的实时监测仍然缺乏探索。本研究提出了一种新颖的方法，通过在环剪切测试中模拟盐溶解过程中的细颗粒损失，实时了解颗粒土在实际应力条件下的机械演变。同时，同时记录了剪切阻力、剪切位移、垂直位移、含盐量和声发射。检测结果表明，样品的不稳定性是由细颗粒的损失引发的。随着细颗粒的逐渐损失，垂直变形和剪切变形以及空隙率均增加。试样中剪切承载力的演变可分为三个阶段：应力减弱，然后加强，最后恢复到初始值。我们推断抗剪性的演变源于其颗粒结构和微观结构的塌陷和重排。高频声发射（约 150 kHz）为这一假设提供了额外的证据，表明伴随粒子损失过程的力链屈曲。此外，样品在较大的初始细粒含量或较高的法向应力下经历了更大的剪切变形和应力减弱。这一发现可能为细颗粒损失过程中颗粒土壤的机械行为提供有价值的见解。