Development and in situ application of actively heated fiber Bragg grating cable for soil water content measurement
The actively heated fiber-optic (AHFO) technology has emerged as a frontier and hotspot in soil water content measurement, offering advantages such as easy installation, large-scale distributed measurement capability, and resistance to electromagnetic interference. However, current AHFO water conten...
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| Format: | Article |
| Language: | English |
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Elsevier
2025-07-01
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| Series: | Journal of Rock Mechanics and Geotechnical Engineering |
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| Online Access: | http://www.sciencedirect.com/science/article/pii/S1674775524004670 |
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| author | Mengya Sun Jie Liu Jin Liu Xing Zheng Xiaoyan Li Junyi Guo Yunqiang Wang Yongping Tong Bin Shi |
| author_facet | Mengya Sun Jie Liu Jin Liu Xing Zheng Xiaoyan Li Junyi Guo Yunqiang Wang Yongping Tong Bin Shi |
| author_sort | Mengya Sun |
| collection | DOAJ |
| description | The actively heated fiber-optic (AHFO) technology has emerged as a frontier and hotspot in soil water content measurement, offering advantages such as easy installation, large-scale distributed measurement capability, and resistance to electromagnetic interference. However, current AHFO water content sensors fail to simultaneously achieve high precision, applicability for deep soil, and automated real-time monitoring, thereby limiting their development and application. Therefore, this study introduces a novel actively heated fiber Bragg grating (AH-FBG) cable. Laboratory tests were conducted to assess the heating uniformity of the AH-FBG cable and to establish the temperature characteristic value (Tt) – soil water content (θ) calibration formula for water content measurement. Subsequently, AH-FBG cables were deployed for in situ soil water content monitoring in a test pit on the Loess Plateau. Through two-year monitoring data verified the accuracy of the AH-FBG cable and elucidated the spatiotemporal distribution of in situ loess water content. Laboratory results demonstrated superior heating uniformity of AH-FBG cable, with a Tt standard deviation of approximately 0.3 °C. In the field, the AH-FBG cable exhibited excellent performance in soil water content measurement, achieving a high accuracy of 0.023 cm3/cm3. Further analysis revealed that the θ fluctuation predominantly occurred within a 10 m depth from the soil surface, with an overall upward trend over the two-year monitoring period; the response of shallow θ to precipitation was significant but exhibited increasing hysteresis with depth; frequent precipitation significantly enhanced water infiltration depth. This study provides technical guidance for high-precision, quasi-distributed, automated and real-time water content measurement of deep soil. |
| format | Article |
| id | doaj-art-e4d2c9f3fbfb4354a9dc3d3eedd7c8b3 |
| institution | Kabale University |
| issn | 1674-7755 |
| language | English |
| publishDate | 2025-07-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Journal of Rock Mechanics and Geotechnical Engineering |
| spelling | doaj-art-e4d2c9f3fbfb4354a9dc3d3eedd7c8b32025-08-20T03:49:54ZengElsevierJournal of Rock Mechanics and Geotechnical Engineering1674-77552025-07-011774579459010.1016/j.jrmge.2024.09.033Development and in situ application of actively heated fiber Bragg grating cable for soil water content measurementMengya Sun0Jie Liu1Jin Liu2Xing Zheng3Xiaoyan Li4Junyi Guo5Yunqiang Wang6Yongping Tong7Bin Shi8School of Earth Sciences and Engineering, Hohai University, Nanjing, 210098, ChinaSchool of Earth Sciences and Engineering, Nanjing University, Nanjing, 210023, China; Corresponding author.School of Earth Sciences and Engineering, Hohai University, Nanjing, 210098, ChinaSchool of Civil Engineering, Chongqing University, Chongqing, 400045, ChinaSchool of Earth Sciences and Engineering, Hohai University, Nanjing, 210098, ChinaSchool of Earth Sciences and Engineering, Nanjing University, Nanjing, 210023, ChinaState Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi’an, 710061, ChinaState Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi’an, 710061, ChinaSchool of Earth Sciences and Engineering, Nanjing University, Nanjing, 210023, China; Corresponding author.The actively heated fiber-optic (AHFO) technology has emerged as a frontier and hotspot in soil water content measurement, offering advantages such as easy installation, large-scale distributed measurement capability, and resistance to electromagnetic interference. However, current AHFO water content sensors fail to simultaneously achieve high precision, applicability for deep soil, and automated real-time monitoring, thereby limiting their development and application. Therefore, this study introduces a novel actively heated fiber Bragg grating (AH-FBG) cable. Laboratory tests were conducted to assess the heating uniformity of the AH-FBG cable and to establish the temperature characteristic value (Tt) – soil water content (θ) calibration formula for water content measurement. Subsequently, AH-FBG cables were deployed for in situ soil water content monitoring in a test pit on the Loess Plateau. Through two-year monitoring data verified the accuracy of the AH-FBG cable and elucidated the spatiotemporal distribution of in situ loess water content. Laboratory results demonstrated superior heating uniformity of AH-FBG cable, with a Tt standard deviation of approximately 0.3 °C. In the field, the AH-FBG cable exhibited excellent performance in soil water content measurement, achieving a high accuracy of 0.023 cm3/cm3. Further analysis revealed that the θ fluctuation predominantly occurred within a 10 m depth from the soil surface, with an overall upward trend over the two-year monitoring period; the response of shallow θ to precipitation was significant but exhibited increasing hysteresis with depth; frequent precipitation significantly enhanced water infiltration depth. This study provides technical guidance for high-precision, quasi-distributed, automated and real-time water content measurement of deep soil.http://www.sciencedirect.com/science/article/pii/S1674775524004670Soil water contentActively heated fiber Bragg grating (AH-FBG) cableSensing cableIn situ monitoringSpatiotemporal distributionApplicability |
| spellingShingle | Mengya Sun Jie Liu Jin Liu Xing Zheng Xiaoyan Li Junyi Guo Yunqiang Wang Yongping Tong Bin Shi Development and in situ application of actively heated fiber Bragg grating cable for soil water content measurement Journal of Rock Mechanics and Geotechnical Engineering Soil water content Actively heated fiber Bragg grating (AH-FBG) cable Sensing cable In situ monitoring Spatiotemporal distribution Applicability |
| title | Development and in situ application of actively heated fiber Bragg grating cable for soil water content measurement |
| title_full | Development and in situ application of actively heated fiber Bragg grating cable for soil water content measurement |
| title_fullStr | Development and in situ application of actively heated fiber Bragg grating cable for soil water content measurement |
| title_full_unstemmed | Development and in situ application of actively heated fiber Bragg grating cable for soil water content measurement |
| title_short | Development and in situ application of actively heated fiber Bragg grating cable for soil water content measurement |
| title_sort | development and in situ application of actively heated fiber bragg grating cable for soil water content measurement |
| topic | Soil water content Actively heated fiber Bragg grating (AH-FBG) cable Sensing cable In situ monitoring Spatiotemporal distribution Applicability |
| url | http://www.sciencedirect.com/science/article/pii/S1674775524004670 |
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