Desiccation cracking of soil subjected to different environmental relative humidity conditions
Desiccation cracking of soil subjected to different environmental relative humidity conditions
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不同环境相对湿度条件下土壤的干裂
DOI：
10.1016/j.enggeo.2022.106536
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发表时间：
2022
影响因子：
7.4
通讯作者：
Bin Shi
中科院分区：
文献类型：
--
作者：
Hao Zeng;Chao-Sheng Tang;Cheng Zhu;Farshid Vahedifard;Qing Cheng;Bin Shi
相对湿度是影响土壤干裂演化的关键环境和气候因子之一。本研究旨在探讨相对湿度的变化如何影响土壤干燥开裂，解决了以往研究中被忽视的一个方面。对一种高脂粘土在15.0%、44.0%、66.0%、76.0%、83.5%和93.7%的相对湿度条件下进行了一系列的室内试验。在测试过程中，对所有样品进行称重并同时拍照，以监测蒸发和表面开裂。利用图像处理技术定量分析了表面裂纹网络的演化过程。结果突出了土壤干燥开裂对RH条件的强烈依赖性。增加RH被发现降低总蒸发速率，并增加开裂开始时的水含量。在高RH条件下，表面裂纹的形成呈现出明显的分级过程，首先发展宽的主裂纹，然后从主裂纹扩展为细的子裂纹。主裂纹和次裂纹扩展速率的不同导致了裂纹长度的多阶段扩展。此外，由于相对湿度的增加，干燥裂纹在给定的水含量趋于更宽和最终的裂纹网络的宽度分布的变化从单峰到双峰的功能。降低RH会导致更快的开裂速率，并使分层过程不可见，导致在蒸发结束时形成更长的总裂纹长度。该研究有助于分析干化开裂诱发地质灾害的潜在形成机制，并评估未来气候变化下地球结构的长期性能。
Relative humidity (RH) is among key environmental and climatic factors that affect the evolution of soil desiccation cracking. This study aims to investigate how RH variations influence soil desiccation cracking, addressing an overlooked aspect in prior studies. A set of laboratory tests were performed to examine a fat clay undergoing desiccation cracking at various controlled RH levels of 15.0%, 44.0%, 66.0%, 76.0%, 83.5% and 93.7%. During testing, all samples were weighed and photographed simultaneously to monitor evaporation and surface cracking. The evolution of the surface crack network was quantitatively analyzed by an image processing technique. Results highlight the strong dependence of soil desiccation cracking on RH conditions. Increasing RH is found to decrease the overall evaporation rate and increase the water content at which cracking starts. Under high RH levels, the formation of surface cracks exhibits an evident hierarchical process with wide primary cracks developing first followed by fine sub-cracks propagating from the primary ones. Different cracking developing rates between a primary crack and sub-crack give rise to the remarkable multi-stage growth of crack length. Besides, owing to an increase in RH, desiccation cracks at a given water content tend to be wider and the width distribution of the final crack network changes from a unimodal to a bimodal feature. Lowering RH causes a faster cracking rate and makes the hierarchical process invisible, resulting in the formation of a longer total crack length at the end of evaporation. This study is expected to help analyze the underlying formation mechanisms of desiccation cracking-inducing geohazards and assess the long-term performance of earth structures under future climate changes.