| 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,2023,42(1):121-129. |
| LI Min,LI Wen,CHEN Yitong,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,2023,42(1):121-129. |
|
| 摘要: |
| 【目的】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3种不同质地的膨胀土在3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；随黏粒量的增大，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：10.13522/j.cnki.ggps.2022121 |
| 分类号: |
| 基金项目: |
|
| Water Release Curves Accounting for Soil Swelling and Shrinking |
|
LI Min, LI Wen, CHEN Yitong, SI Bingcheng
|
|
1. Key Laboratory of agricultural water and soil engineering in arid areas, Ministry of education, Northwest A&F University,
Yangling 712100, China; 2. Department of Soil Science, University of Saskatchewan, Saskatoon S7N5A8, Canada;
3. School of Resource and Environmental Engineering, Ludong University, Yantai 264000, China
|
| Abstract: |
| 【Objective】Heavy-textured soils tend to swell or shrink following rewetting or drying, while most water release curves measured from such soils do not consider such effects. The purpose of this paper is to investigate these and proposes an improved model to account for soil swelling and shrink.【Method】Changes in Soil moisture and matric potential during three wetting-drying cycles in three soils were measured using thermo-TDR probe and soil water potential probe, respectively, and the results obtained from each cycle for each soil were fitted to the van Genuchten formula. We introduced a shrinking percentage parameter to improve the fitting of the van Genuchten formula.【Result】The heat pulse probe improved soil volume measurement, with the relative error reduced from 10%~40% to less than 10% and the associated root mean square errors reduced from 0.3~0.4 g/cm3 to less than 0.1 g/cm3. Increasing dry-wet cycles reduced the values of the parameters α and n in the van Genuchten formula. The influence of soil water on soil volume waned as soil water content decreased. The values of the parameters α and n in the van Genuchten formula both decreased as clay content increased. Accounting for the shrinkage in the modified model improved the fitting compared to the original van Genuchten formula that does not consider soil deformation. 【Conclusion】The heat pulse probe can accurately measure change in soil volume induced by wetting and drying, and the proposed model considering volumetric change of soils following wetting or drying improves the fitting of the van Genuchten formula to the measured data. |
| Key words: three-dimensional soil water characteristic curve; expansive soil; volume mass; thermo-TDR technology |
