Effect of Water Content on Internal Erosion of an Unsaturated Slope
Effect of Water Content on Internal Erosion of an Unsaturated Slope
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DOI：
10.1061/9780784484654.043
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发表时间：
2023-03
期刊：
影响因子：
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通讯作者：
Olaniyi Afolayan;Josh McLeod;J. Montgomery
中科院分区：
文献类型：
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作者：
Olaniyi Afolayan;Josh McLeod;J. Montgomery
土壤管道是土壤颗粒逐渐和渐进的侵蚀，导致水流经土壤时形成空洞（开口管）。在大坝工程中，这种类型的内部侵蚀通常被称为集中泄漏侵蚀，并已成为多个大坝失败的原因。在许多滑坡中也观察到土壤管状现象，这对山坡和农业区的土壤退化有重大影响。尽管有这些重要的影响，但对土壤管道如何发展和进步以及哪些因素控制管道稳定性的了解仍然有限。分析土壤管道或集中泄漏侵蚀的一个重大挑战是，它通常发生在存在非饱和条件的渗透区。然而，大多数研究内部侵蚀的研究都集中在饱和条件下，很少有研究检查非饱和水力特性（即空气进入值，基质吸力等）在内部侵蚀可能性中的作用。因此，本研究旨在从非饱和土力学的角度探讨土壤管道内侵蚀速率的控制机制。在不同含水率的小斜坡上进行了侵蚀管道的形成和发展的实验研究。并对土样进行了非饱和水力特性测试。结果表明，管道形成的可能性随土壤含水率和吸力的变化而变化，管道坍塌的可能性也随土壤含水率和吸力的变化而变化。这表明非饱和土的性质是理解斜坡管道形成和发展的关键。
Soil piping is the gradual and progressive erosion of soil grains, causing a void (open pipe) to form as water flows through the soil. In dam engineering, this type of internal erosion is often referred to as concentrated leak erosion and has been a cause of failure at multiple dams. Soil piping has also been observed in many landslides and contributes significantly to soil degradation in hillslopes and agricultural areas. Despite these many important impacts, there is still limited understanding of how soil pipes develop and progress and what factors control pipe stability. One of the significant challenges with analyzing soil piping, or concentrated leak erosion, is that it typically occurs in the vadose zone, where unsaturated conditions are present. However, most studies examining internal erosion have focused on saturated conditions, and few studies have examined the role unsaturated hydraulic properties (i.e., air entry value, matric suction, etc.) may play in the likelihood of internal erosion. Consequently, this study aims to explore the mechanisms controlling the erosion rate within soil pipes from the perspective of unsaturated soil mechanics. Bench-scale experiments were performed to examine the formation and progression of an eroded pipe in a small slope constructed at different water contents. Soil samples were also tested to measure its unsaturated hydraulic properties. The results show that the likelihood of pipe formation varies with the moisture content and, therefore, suction in the soil, as does the potential for pipe collapse. This demonstrates that unsaturated soil properties are key to understanding the formation and progression of piping in slopes.