Soil desiccation cracking as a consequence of severe environmental changes alters soil deformation mechanisms significantly. Therefore, this study aims to explore the effect of crack characteristics and environmental conditions on the heterogeneous deformation of desiccation-cracked soils using thermo-hydro-mechanical analyses. The model framework consists of balance equations, thermal, hydraulic, and mechanical constitutive equations, while the model scenarios were determined based on statistical analyses. The meteorological record of Qom city was used for three years, from 2015 to 2017, to capture long-term behaviour under wetting-drying cycles. Findings revealed that cracks extend the deformation range, potentially up to six times, with variation based on crack dimensions and spacing. Notably, narrower cracks experienced more pronounced deformation than wider ones. The cracked soil with a crack depth of 2.5 m showed 1.5 times higher swelling and subsidence than crack depth of 1 m. Furthermore, the wider cracks indicated a lower rate of increase in their dimensions compared to the initial state during drying. The investigation also highlights the mechanisms of soil surface shape due to swelling and shrinkage, resulting in concave and convex surfaces, respectively. The results provide new perspectives on the behaviour of fine-grained deposits in arid to semi-arid climates with deep groundwater levels.

中文翻译：

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干燥裂缝粘土岩层中非均质沉降和膨胀的热-水-力学建模


由于严重的环境变化而导致的土壤干燥开裂显着改变了土壤变形机制。因此，本研究旨在通过热-水-力学分析来探索裂缝特征和环境条件对干燥裂缝土壤非均质变形的影响。模型框架由平衡方程、热、液压和机械本构方程组成，而模型场景则根据统计分析确定。从 2015 年到 2017 年，库姆市的气象记录使用了三年，以捕捉干湿循环下的长期行为。研究结果表明，裂纹将变形范围扩大了，可能高达六倍，其变化基于裂纹尺寸和间距。值得注意的是，较窄的裂缝比较宽的裂缝经历更明显的变形。裂缝深度为 2.5 m 的裂缝土壤的膨胀和沉降是裂缝深度 1 m 的 1.5 倍。此外，较宽的裂纹表明与干燥过程中的初始状态相比，其尺寸增加的速率较低。该研究还强调了由于膨胀和收缩而导致的土壤表面形状的机制，分别导致凹面和凸面。研究结果为细粒矿床在地下水位较深的干旱至半干旱气候中的行为提供了新的视角。