| Cite this article: | 李敏,李雯,陈祎彤,等.膨胀土干湿循环自然胀缩下土壤水分特征三维曲线研究[J].灌溉排水学报,0,():-. |
| limin,liwen,chenyitong,et al.膨胀土干湿循环自然胀缩下土壤水分特征三维曲线研究[J].灌溉排水学报,0,():-. |
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| Study on soil three-dimensional soil water characteristic curve of expansive soil under natural swell-shrink in the process of dry-wet cycles |
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limin1,2, liwen1,2, chenyitong1,2, sibingcheng3
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1.Northwest A&2.F University;3.Department of Soil Science, University of Saskatchewan
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| Abstract: |
| 【Background】The influence of bulk volume mass change is always ignored in determination of soil water characteristic curve, which causes large errors in the study of expansive soil with strong swelling and shrinkage.【Objective】This study establishes a three-dimensional soil water characteristic curve of expansive soil under natural swell-shrink, and explores the change laws of their fitting parameters.【Method】Using the thermo-TDR probes and soil water potential probes, the dynamic variations of bulk volume mass of expansive soil was considered in determination of soil water characteristic curve, the three-dimensional soil water characteristic curves of expansive soils with three different textures were obtained in three alternating drying and wetting cycles.【Result】The in-situ spacing correction method of heat pulse probe can effectively improve the measurement accuracy of soil bulk volume mass. The deviations of relative error with correction reduced from 10%-40% to far less than 10%, and the root mean square errors reduced from 0.3-0.4 g/cm3 to far less than 0.1 g/cm3. The fitting of van Genuchten Model was improved by introducing the parameter of shrinking percentage. As soil dry-wet cycles increase, the parameters α and n values decreased gradually. In the process of dehumidification, the influence of soil water on soil bulk volume mass and suction was weakened. With the increase of clay content, the fitting parameters α and n values decreased, and the improved van Genuchten Model fitted better than original model.【Conclusion】The in-situ probe spacing correction method in measuring strong expansive soil can significantly improve the accuracy, and the establishment of three dimensional soil water characteristic curve by considering bulk volume mass describes soil water-retention relations more realistically. |
| Key words: The three-dimensional curve of soil moisture characteristics; Expansive soil; volume mass; Thermo-TDR Technology |
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