Drought-induced soil desiccation cracking is a common natural phenomenon on the earth surface, which plays a significant role in influencing the hydro-mechanical behavior of soils across various earthen engineering applications. However, there is still a scarcity of related studies investigating how field soil desiccation cracking responds to climate action. This study develops an innovative geophysical monitoring framework for investigating field desiccation cracking behaviors by utilizing the distributed fiber optical sensing (DFOS) technique based on optical frequency domain reflectometry (OFDR). The feasibility and significant potential of the DFOS-OFDR framework in advancing soil desiccation cracking research is demonstrated through the implementation of field monitoring tests. The results not only indicate that the strain distribution curves of fiber optic cables at different depths provide insights into the soil shrinkage characteristics and the crack localization capability but also demonstrate the early detection capability of the DFOS-OFDR framework for soil desiccation cracking from a visual perspective. Importantly, the field monitoring tests reveal that under the influence of climate change, desiccation cracking exhibits a distinctive pattern of periodic propagation and narrowing. This intriguing phenomenon is referred to as “soil crack breathing.” Additionally, the DFOS-OFDR framework exhibits enhanced sensitivity in sensing the soil crack breathing phenomenon than visual observation methods. This innovative geophysical monitoring framework not only enables real-time observation, continuous measurement, and high-resolution characterization of soil desiccation cracking behavior but also serves as a valuable high-precision observational method for investigating the complex soil-atmosphere interactions under the influence of climate change.

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土壤干燥开裂的呼吸现象：来自新地球物理观测的见解

干旱引起的土壤干燥开裂是地球表面常见的自然现象，在影响各种土工程应用中土壤的水力力学行为方面发挥着重要作用。然而，目前尚缺乏探讨田间土壤干燥开裂如何响应气候作用的相关研究。本研究开发了一种创新的地球物理监测框架，利用基于光频域反射计（OFDR）的分布式光纤传感（DFOS）技术来研究现场干燥裂纹行为。通过现场监测测试，证明了 DFOS-OFDR 框架在推进土壤干燥开裂研究方面的可行性和巨大潜力。结果不仅表明光缆在不同深度的应变分布曲线可以深入了解土壤收缩特征和裂缝定位能力，而且从视觉角度证明了DFOS-OFDR框架对土壤干燥裂缝的早期检测能力。重要的是，现场监测测试表明，在气候变化的影响下，干燥裂纹表现出独特的周期性扩展和缩小模式。这种有趣的现象被称为“土壤裂缝呼吸”。此外，与视觉观察方法相比，DFOS-OFDR 框架在感知土壤裂缝呼吸现象方面表现出更高的灵敏度。这种创新的地球物理监测框架不仅能够实时观测、连续测量和高分辨率表征土壤干燥开裂行为，而且为研究气候影响下复杂的土壤-大气相互作用提供了一种有价值的高精度观测方法改变。