Soil desiccation cracking is a common natural phenomenon under extreme climatic conditions. The presence of cracks adversely affects mechanical and hydraulic properties of soils, leading to a series of geological, geotechnical, hydrological, and environmental problems. Desiccation cracks increase the soil evaporation rate and reduce the soil water retention capacity, thereby accelerating desertification. Cracks reduce the soil shear strength, increase the soil hydraulic conductivity, create preferential flow pathways for the migration of fluids and contaminants, and accelerate soil weathering and erosion. All of the aforementioned effects can undermine the stability of built environment (e.g., foundations, levees, earthen dams, landfill covers, roads) and trigger a suite of natural hazards (e.g., landslides, erosion). Therefore, understanding the real-time development patterns and potential evolution mechanisms of soil cracks is crucial for preventing and mitigating engineering geological disasters under extreme climatic conditions.
Recently, distributed optical fiber sensing (DFOS) technique has become increasingly prevalent in geological and geotechnical engineering monitoring. This widespread adoption is attributed to its notable advantages, including robust anti-interference capabilities, corrosion resistance, high sensitivity, and precision. Considering the characteristics and advantages of this technology, Jin-Jian Xu, a PhD student at our center, under the guidance of his mentor, proposes a novel framework for monitoring and early detecting soil cracking by utilizing the DFOS technique based on optical frequency domain reflectometry (OFDR). The results reveal a strong correlation between the spatiotemporal evolution of soil strain and crack, confirming the efficacy and reliability of the proposed framework. Furthermore, DFOS-OFDR framework demonstrated promising results to predict the position and width of cracks. This study is of great significance for a profound understanding of the formation mechanisms of soil desiccation cracking and offers new technical insights for predicting the development of these cracks.
Figure1 Spatiotemporal evolution of soil desiccation cracking patterns and OFDR sensing strain during the drying process
The study was accepted by《Géotechnique》(Title: Monitoring and Early Detection of Soil Desiccation Cracking Using Distributed Fiber Optical Sensing). Jin-Jian Xu (PhD student) is the first author of the paper, and Professor Chao-Sheng Tang and Associate Professor Qing Cheng is the corresponding author. The work was supported by the National Natural Science Foundation of China, National Key Research and Development Program of China, the Natural Science Foundation of Jiangsu Province and the Fundamental Research Funds for the Central Universities.
Paper link: https://doi.org/10.1680/jgeot.21.00397
Other related papers:
Xu, J. J., Tang, C. S., Yang, Y., Li, L., Zhang, H., Cheng, Q., ... & Shi, B. (2024). Breathing phenomenon of soil desiccation cracking: Insights from novel geophysical observations. Journal of Geophysical Research: Earth Surface, 129(1), e2023JF007318. (https://doi.org/10.1029/2023JF007318)
Xu, J. J., Zhang, H., Tang, C. S., Cheng, Q., Liu, B., & Shi, B. (2022). Automatic soil desiccation crack recognition using deep learning. Geotechnique, 72(4), 337-349. (https://doi.org/10.1680/jgeot.20.P.091)
Xu, J. J., Zhang, H., Tang, C. S., Cheng, Q., Tian, B. G., Liu, B., & Shi, B. (2022). Automatic soil crack recognition under uneven illumination condition with the application of artificial intelligence. Engineering Geology, 296, 106495. (https://doi.org/10.1016/j.enggeo.2021.106495)
Xu, J. J., Tang, C. S., Cheng, Q., Xu, Q. L., Inyang, H. I., Lin, Z. Y., & Shi, B. (2021). Investigation on desiccation cracking behavior of clayey soils with a perspective of fracture mechanics: a review. Journal of Soils and Sediments, 1-30. (https://doi.org/10.1007/s11368-021-03082-y)