考虑体积变化影响的武汉粉质红黏土土水特征曲线

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关键词：体积变化；干燥收缩试验；轴平移方法；武汉粉质红黏土；土水特征曲线中图分类号：TU43 文献标志码：A 文章编号：1674-8530（2025）12-1254-08DOI： 10.3969/j.issn.1674-8530.24.0107

Abstract：To analyze the relationship between water content changes and volumetric shrinkage during soil dehumidification，the efect of volume change on the soil-water characteristic curve was comprehensively considered and axis translation method wasused to determine the soil-water characteristic curve of Wuhan silty red clay.Additionally，based on the soil deformation image measurement platform，the variation of volume，quality moisture content and volumetric water content of the soil during the dehumidification process were measured. On this basis，the soil moisture content under the two experimental conditions of axial translation and drying shrinkage test was used as a link，and the volume change was integrated with the matrix suction test results to give the red clay soil-water characteristic curve related to the porosity ratio.Theresults show that the volume change of soil has a significant effecton thesoil-watercharacteristic curve，and theactual dry density of clay with aninitialdrydensity of 1.45g/cm3 reaches 1.60g/cm3 after final dehumidification，leading to a more compact pore structure.Considering the correction for shrinkage volume change，the value of the matrix suction at the same saturation of O.442 increases by 397kPa over the original value，suggesting that the soil sample has stronger water retention properties.This study provides a valuable reference for guiding agricultural irrigation and sustainable agricultural development.

Key words：volume change;drying shrinkage test;axis translation method; Wuhan silty red clay; soil-water characteristic curve

中国粉质红黏土广泛分布于湖北、湖南、广西、贵州等南方地区.武汉地区粉质红黏土属于第三类红黏土，约占武汉市总面积的 11.22% ，主要分布在武汉周边和长江中下游地区的低丘陵垄岗地形中，肥力适中[1-3].该地区属于典型的亚热带季风气候，为粉质红黏土的形成和分布提供了炎热多雨的条件，特别是在季风作用和降雨侵蚀、淋溶作用下，进一步促进了粉质黏土在武汉地区的发育和广泛分布[4-6].由于该地区降雨蒸发分布不均、易涝易旱，常出现季节性干旱，从而阻碍了农作物生长.为此，精确判断土壤持水能力、分析农作物在不同生长阶段水分需求，能够提升农业水资源利用效率，达到节水增产的效果.这对于日照充足、雨量充沛、粉质红黏土分布广泛的湖北、湖南地区具有重要参考价值.

土壤脱湿过程中的板结硬化和吸力变化是判别农作物生长性能的重要条件[8].大多农作物根系生长在土壤中同时含有空气和水分的非饱和带，研究该区域的非饱和土的土水特征曲线不仅是研究土壤水分运移的关键，还有助于提高土壤水分利用效率.合理确定土水特征曲线及蒸发吸力提升过程中的土壤收缩体变，能够更精确地判断土壤持水能力，进而分析农作物在不同生长阶段的水分需求，对优化农业灌溉策略、确定植物种植土壤密度、提升水资源利用效率以及响应国家节水优先政策具有重要作用[10-12].研究表明，土水特征曲线与土壤的干密度、孔隙分布等因素相关，土壤在蒸发脱湿过程中产生的体积收缩会造成干密度增大，致使实际测量的土水特征曲线与预期孔隙状态下测试不完全一致[13-16].因此，有必要考虑土壤孔隙结构变化对土水特征曲线的影响。（剩余14630字）