| 引用本文: | 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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| 摘要: |
| 【目的】本研究建立了自然胀缩下膨胀土的土壤水分特征三维曲线并探究其拟合参数的变化规律。【方法】利用thermo-TDR探针和土壤水势探针，在测定土壤水分特征曲线的过程中考虑膨胀土体积质量动态变化，得到三种不同质地的膨胀土在三个干湿交替周期中土壤水分特征三维曲线的变化规律。【结果】发现热脉冲探针原位间距校正法能有效提高土壤体积质量的测定准确度，校正后RE由总体10%-40%的偏差降低为总体远小于10%，RMSE经校正后总体由0.3-0.4 g/cm3降低为远小于0.1 g/cm3；引入收缩率这一体积质量参数改进van Genuchten模型，得到较好的土壤水分特征三维曲线拟合结果；随着土壤干湿循环次数增加，模型参数α和n值不断减小，在脱湿过程中，含水率对体积质量和吸力变化的影响在不断削弱；随粘粒含量的增大，α和n值呈减小趋势，且改进后的van Genuchten模型拟合效果更好。【结论】原位探针间距校正法对强胀缩土壤的测定准确度提升效果显著，建立考虑体积质量的土壤水分特征三维曲线能更真实描述土壤水分与水势间的关系。 |
| 关键词: 土壤水分特征三维曲线；膨胀土；体积质量；Thermo-TDR技术 |
| DOI： |
| 分类号:S152.7 |
| 基金项目:国家重点研发计划资助(2021YFD1900700)；国家自然科学基金(41877017) |
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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 |
